JPH09269876A - Host-based printer system and data transmission / reception method therefor - Google Patents

Abstract

(57) Abstract: A host-based printer system is realized in an ECP mode capable of printing at higher speed. SOLUTION: The write pointer WP = 0, the read pointer RP = 0, and the limit pointer LP = 1 are initialized so that the write DMA controller 34 can write only 1 byte of data to the RAM 33 (S10). When 1 byte of data is written, WP = LP and an interrupt occurs, the data of WP-1 is read, and WP ← WP
-1, and command interpretation is executed (S20 to S50). When the data number setting command is received, LP ← (WP + data number) is set, and when an interrupt signal is input, LP ← WP + 1 is set and the process returns to S20 (S100 to S130). By the above processing,
The command data in the data transmitted in the ECP mode is substantially deleted from the RAM 33 by overwriting,
Only the image data is written.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a host-based printer system in which image data is formed in advance on the host side and the image data and command data are output to a printer for printing.

[0002]

2. Description of the Related Art Conventionally, when a document created by a personal computer (personal computer) is printed by a printer, print data represented by a page description language (PDL) is output from the personal computer and the printer side C is used.
There is known a system (hereinafter, referred to as a "PDL system") configured to expand the image data (bitmap data or compressed data thereof) by a PU and perform printing.

However, in recent years, the number of personal computers equipped with graphic accelerators has increased as the functionality of personal computers has increased. Therefore, by using this graphic accelerator, bitmap data is created at high speed on the personal computer side, and this is compressed and transferred to the printer at high speed, thereby realizing a high-speed and low-cost printer. Such a printing system is called a host-based printer system.

In this host-based printer system,
Further speeding up is achieved by adopting a DMA (Direct Memory Access) controller on the printer side and writing the received data into the receiving buffer at high speed. By the way, a Centronics interface is generally adopted for data transmission / reception in a printing system.
Data is being transferred by the shake hand method according to the Centronics standard.

In the shake hand system of Centronics, first, when the personal computer outputs data, one byte of data is set and the strobe signal is set to Low for a predetermined time so that the data is set in the printer CPU. Let me know. The falling edge of the strobe signal and the shake hand are performed to set the busy signal to High on the printer side to read the data from the data line. Then, when the data reading is completed, the busy signal is dropped to Low. The personal computer side performs the falling of the busy signal and the shake hand to execute the next data set and strobe signal change. As described above, since the shake hand is used only for the falling signal, it is necessary to keep the time for keeping the strobe signal Low for safety, and the data transfer rate is 100 Kbyte /
It is only about sec.

On the other hand, IEEE 1284 has been defined as a new standard for enabling bidirectional communication of data by the Centronics interface. This IEEE
As the data transfer method in the E1284 standard, the compatible mode in which only the falling signal is shake handed, the ECP mode in which the falling signal and the rising signal are shake handed or E
The PP mode is defined.

Explaining the ECP mode, first,
When a personal computer outputs data, it sets 1 byte of data and sets the strobe signal to Low. On the printer side, the falling edge of the strobe signal is detected to read the data, and when the data reading is completed, the peripheral ACK signal is set to High. The personal computer shakes and hands the rising edge of the peripheral ACK signal to return the strobe signal to high, and the printer side performs the shaking and handing of the strobe signal to return the peripheral ACK signal to the low level. Then, the falling edge of the peripheral ACK signal is shake-handed and the next data set and the strobe signal are inverted.
In this way, in ECP mode, since the shake hand is performed not only at the falling edge but also at the rising edge, it is not necessary to lengthen the strobe signal as in the Centronics method, and the data transfer rate becomes astonishingly high, which is 2 Mby.
It becomes possible to achieve about te / sec. In the EPP mode, the way of using the signal line is different from the ECP mode, but the content is the same shake hand system.

For this reason, recently, the use of this ECP mode in a printing system has been studied,
It has been found that the PDL system can be applied without problems.

[0009]

However, in the host-based printer system, command data and image data having different characteristics are sent. Therefore, only writing one page at a high speed using the DMA controller makes it possible to write one page worth of data. Command data may be inserted between image data. This is because the image data has a larger amount of data than the data by PDL, and if the image data for one page is not divided into several pieces and output, there is a problem such as pressure on the memory on the personal computer side. Because there is. Further, when the image data for one page is small, the data for a plurality of pages can be output at one time, but in this case, the command data is inserted between the pages.

In the host-based printer system, the data is sequentially read from the reception buffer by using the read DMA without using the CPU, and the data is decompressed as necessary and then output to the printer engine unit. If command data is sandwiched between image data, the CPU may not be able to interpret the command data, and normal printing may not be possible.

Therefore, it is an object of the present invention to realize a host-based printer system in the ECP mode capable of printing at higher speed.

[0012]

Means for Solving the Problems, Embodiments of the Invention, and Effects of the Invention The host-based printer system of the present invention made to achieve the above-mentioned object forms image data for printing in advance on the host side, In a host-based printer system that outputs the image data and command data for printing to a printer for printing, at least the transmission and reception of the image data is performed according to the EC of the IEEE1284 standard.
A data transmission / reception means for performing a shake hand method in the P mode or the EPP mode is provided, and a write DMA controller for receiving the image data and writing the same in a reception buffer on the printer side, and an image from the reception buffer for executing printing. A read DMA controller for reading data is provided, and the reception buffer is provided with image data storage means for storing data so that command data is not interposed between image data for one page. Specifically, the image data accumulating unit distinguishes the command data from the image data, and accumulates the data in the reception buffer so as not to leave the command data between the image data and the image data in the reception buffer. It may be configured as a means.

According to the host-based printer system of the present invention, the image data is always in ECP mode or EPP.
Since it is transmitted by the shake hand method in the mode,
High-speed output to the printer. The image data thus transferred at high speed can be written at high speed in the reception buffer by using the write DMA controller. Therefore,
The data transfer does not limit the printing speed of the system. In the present invention, the image data storage means is
Since the data is stored so that the command data is not interposed between the image data for one page, the read DMA controller only needs to read the data one after another, and the rate is not limited here. Then, the image data accumulating unit distinguishes the command data from the image data, and accumulates the data in the reception buffer so as not to leave the command data between the image data and the image data in the reception buffer. The command data will not be sandwiched between the image data of (1) and (2) and will not be left unprintable.

As a more specific configuration of such a host-based printer system, the data transmission / reception means performs transmission / reception of command data and image data for printing by a shake hand system of ECP mode or EPP mode of the IEEE1284 standard. The writing side of the write DMA controller may be configured to be temporarily stopped when one byte of data is received and to be continuously received by the printer. A reception state switching means for switching, and the above 1
In the byte receiving state, the write DMA controller reads and interprets the data written in the receiving buffer, and based on the interpretation result, sets the switching condition of the receiving state by the receiving state switching means. The image data writing unit is configured by including a unit and an overwriting unit that overwrites the data written in the 1-byte receiving state when writing data in the receiving buffer in the continuous receiving state. be able to.

In this system, both command data and image data are transmitted and received in ECP mode or EPP mode. And DM for writing both command data and image data
A writes in the reception buffer, but the image data is overwritten on the command data by the overwriting means. Therefore, even when the image data for one page is divided into a plurality of pieces and output, the command data that is sandwiched between the image data and transmitted does not interfere. Further, by switching between the 1-byte receiving state and the continuous receiving state, the high-speed transfer of data, which is the original merit of the ECP mode or the EPP mode, is intentionally limited, and a data structure peculiar to the host-based printer is supported. Specifically, interpret the command data in the 1-byte reception state,
The command data is used to grasp the number of bytes of the image data and determine how long the continuous reception state should be continued.

More specifically, the receiving state switching means is constituted by a limit pointer for giving a write pointer stop condition by the write DMA controller, and the switching condition setting means is changed to the limit pointer. The 1-byte reception state is set by setting the pointer next to the current write pointer, and the continuous reception state is set by setting the previous pointer by the number of bytes of the image data found as a result of command interpretation in the limit pointer. The overwrite means can be configured as a means for performing the overwrite by returning a write pointer.

Alternatively, the reception state switching means is constituted by a counter for giving the amount of movement of the write pointer by the write DMA controller, and the switching condition setting means sets the number of bytes to 1 in the counter. It is configured as a means for setting a continuous reception status by setting a byte reception status and setting the number of bytes of image data found as a result of command interpretation in the counter, and the overwrite means is configured to perform the overwrite by returning a write pointer. It can be configured as a means for performing.

In these systems, the limit pointer or counter realizes the 1-byte reception state, and these are used so that the continuous reception state can be restored to the 1-byte reception state again. Then, the overwriting means returns the write pointer and overwrites the image data there so that no command data remains.

In these host-based printer systems, it is preferable that the write pointer is returned to the immediately preceding state after the switching condition setting means has read the data in the 1-byte reception state. By doing this, the first command data will not remain in the reception buffer.

As a host-based printer system having another specific structure, the data transmission / reception means uses the IEEE for transmitting / receiving the command data and image data for printing.
An identification for configuring when performing the shake hand method of the ECP mode or the EPP mode of the 1284 standard, and for distinguishing between the time when the command data is output and the time when the image data is output to the host side. A signal output unit is provided, and a DM for writing is provided on the printer side while the identification signal means output of command data.
A central processing unit is provided which, while the A controller is in a stopped state, receives and interprets command data by itself and causes the write DMA controller to receive image data while the identification signal means output of image data. Thus, the image data writing means can be configured.

In this system, a certain signal on the host side discriminates whether the data transmitted in the ECP mode or the EPP mode is command data or image data. Since the command data is directly received by the central processing unit itself, it is never written in the reception buffer in the first place, and only the image data is written in the write DMA.
It will be written at high speed by the controller.

As another specific configuration, the data transmission / reception means uses the IEEE128 for image data transmission / reception.
4 standard ECP mode or EPP mode shake hand method is used, and command data is transmitted and received by IEEE12.
It is configured as means for performing the 84 standard compatible mode shake hand method, and the command data transmitted under the compatible mode is directly received and interpreted by the printer side, and the command data is transmitted in the ECP mode or the EPP mode.
By providing a central processing unit that causes the writing DMA controller to receive the data transmitted until the termination phase is started after the completion of the setup phase in the mode, the image data writing means is provided. It may be configured.

In this case, in the compatible mode, the central processing unit receives the data and does not write the command data in the reception buffer.
In the mode, the writing DMA controller receives only the image data and writes it in the reception buffer. Therefore, even if one page of image data is output from the host as data in which command data is sandwiched between them, only image data is stored in the reception buffer, and printing cannot be disabled.

As a method of handling data between the host and the printer in the host-based printer system of the present invention, data for transmitting / receiving command data and image data for printing by the shake hand method of the ECP mode or the EPP mode of the IEEE1284 standard is used. The sending and receiving method, the command data for printing and the image data are IEEE
Data transmission / reception in which transmission / reception is performed by the E1284 standard ECP mode or EPP mode shake hand method, and an inversion signal that is inverted when the command data is being output and image data is being output is also output from the host side. Method or image data transmission / reception by IEEE
The E1284 standard ECP mode or EPP mode shake hand method is used to send and receive command data.
Any of the data transmission / reception methods performed by the shake hand method of the compatible mode of the EE1284 standard may be adopted.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments will be described below with reference to the drawings in order to make the embodiments of the present invention easier to understand.
It should be noted that all of the examples described below are IEEE12.
It is configured to perform two-way communication according to the 84 standard.

As shown in FIG. 1, the printer system 1 of the first embodiment comprises a print host 2 and a laser printer 3. The print host 2 and the laser printer 3 are electrically connected via a Centronics cable 4 for transmitting / receiving parallel data. The host 2 outputs bitmapped image data and command data,
It is configured so that it can function as a so-called host-based printer. The printer 3 includes an engine mechanism such as a printing mechanism for printing with a laser beam system and a paper feeding mechanism, and a control unit. Since the engine mechanism itself is the same as an existing laser printer, its detailed description is omitted.

In this embodiment, the host 2 is the printer 3
In contrast, print data having a structure as shown in FIG. 2A is output. That is, in the print data, a command for giving the data length etc. is arranged in the first 5 bytes,
After that, the compressed image data is arranged, and then one page of data is arranged in the order of command, image data, command, image data, and so on. Finally, a 2-byte form feed command for instructing print execution is arranged. It will be arranged.
The command and image data are both I
It is adapted to be transmitted in the ECP mode of the EEE1284 standard. Specifically, as shown in FIG. 2B, EC
Both the command data and the image data are transmitted within the forward phase of the P mode.

As shown in FIG. 3, the control unit 30 has a CPU 31 serving as the center of control, a ROM 32 storing a control program, a RAM 33 functioning as a ring buffer, and a write capable of directly accessing the RAM 33. The read DMA controller 34 and the read DMA controller 35 are provided.

The write DMA controller 34 is connected to the reception unit 36 of the Centronics interface and writes the data received from the host 2 into the RAM 33 as it is. The write DMA controller 34 does not distinguish between command data and image data, and writes the data received by the receiving unit 36 into the address of the write pointer WP in the RAM 33, which is designated by the write pointer management unit 37. . And DM for writing
The A controller 34 outputs an increment signal to the write pointer management unit 37 each time one byte of data is written.

The read DMA controller 35 has a read pointer R designated by the read pointer management unit 38.
The data written in the address P is read byte by byte, and the increment signal is output to the read pointer management unit 38. The read data is decompressed by the decoder 39 arranged on the downstream side, transferred to the line shift buffer 40, and output to the engine unit 41 equipped with a laser diode and the like.

Write pointer WP and read pointer RP
Is input to the first comparator 42. The first comparator 42 is configured to output a high level signal when WP = RP. The write pointer WP is further input to the second comparator 44 and compared with the limit pointer LP designated by the limit pointer management unit 43, which is a feature of this embodiment. The second comparator 44 is configured to output a high level signal when WP = LP. Note that the limit pointer management unit 43 uses the CPU 3
The value of LP is set by 1. The second comparator 44 also outputs to the read DMA controller 35, and plays a role of stopping the read DMA controller 35 when WP = RP. On the other hand, the reading DMA controller 35 is activated by the CPU 31.

Then, the first and second comparators 42,
The output of 44 is input to the OR circuit 45. The output of the OR circuit 45 is input to an Ack generating unit 46 and a receiving unit 36 that generate an nPheriphAck signal (peripheral ACK signal, hereinafter simply referred to as “Ack”). The Ack generating unit 46 is the receiving unit 36 or the OR circuit 4.
When a High level signal is output from any one of 5 to 5, AcK is generated for the host 2 and plays a role of controlling the output state of data on the host 2 side.

Further, the first and second comparators 42, 4
The output of 4 is also input to the inverter 47 in addition to the OR circuit 45, and its inverted signal is input to the interrupt terminal of the CPU 31. The CPU 31 is configured to execute an interrupt process when the interrupt signal goes low.

The CPU 31 is configured to read command data from the RAM 33 and process it. In addition, all components other than the CPU 31, the ROM 32, and the RAM 33 are configured as a single ASIC. Next, the processing contents of the CPU 31 of the embodiment will be described.

As shown in FIG. 4, the CPU 31 first sets the write pointer WP, the read pointer RP, and the limit pointer LP to WP = 0, RP = 0, LP =, respectively.
It is initialized to 1 (S10). This allows the write DMA
The controller 34 can write only one byte of data to the RAM 33. When 1 byte of data is written in the RAM 33, WP = LP and an interrupt occurs. Upon receipt of this interrupt, the CPU
31 reads the data written in the address of WP-1 (S20, S30), decrements WP ← WP-1 and the write pointer (S40), and executes command interpretation of the data read previously (S50). .

As a result of this command interpretation, the form feed "

When "F" is designated (S60 = YE
S), the engine unit 41 is started (S70), and after the sheet position is confirmed by the sensor of the engine unit 41, a start command is output to the reading DMA controller 35 (S8).
0, S90).

On the other hand, when the form feed is not instructed (S60 = NO), the data number setting command "

It is determined whether "G *** (*** is the number of data indicated by 3 bytes)" has been received (S10).
0). Data number setting command

If not G *** "(S100 = N
O), and the processing of S20 and thereafter is executed again. Data number setting command

G *** "(S100 = Y
ES), and sets a value obtained by adding the number of bytes of data to the value of the current write pointer WP to the limit pointer LP (S
110), and then waits until an interrupt signal comes in (S
120). When the interrupt signal is input, the limit pointer LP is set to a value obtained by adding 1 to the write pointer WP at that time, and the process returns to S20 (S130).

Through the above processing, the operation of the write DMA controller 34 is controlled as follows. Since the writing DMA controller 34 is initially permitted to receive one byte in S10, it receives one byte of data. Then, the write pointer management unit 3
The increment signal is input to 7, and WP = LP = 1. As a result, the write DMA controller 34 stops. Further, a High level signal is output from the second comparator. This High level signal is inverted by the inverter, the CPU 31 is interrupted and S2
0 is executed. As a result, the data just written is read and the command is interpreted. During this time,
Since WP is decremented by S30, the write DMA controller 34 starts operating again. Then, the address in which the 1-byte data read previously is written is overwritten with the next 1-byte data.

In this way, the command interpretation by the CPU 31 is executed while writing the data number setting command arranged before the image data byte by byte and overwriting. In this way, when 1-byte writing and overwriting are repeated and the interpretation of the data number setting command is completed, the write pointer WP corresponding to the number of data (***) is set since it is image data from the next time. As a result, the write DMA controller 34 waits until WP = LP.
By the shake hand method peculiar to the ECP mode, the image data is received and written into the RAM 33 at high speed. When WP = LP, write D
Since the MA controller 34 is stopped and an interrupt signal is generated, the CPU 31 starts operating again and sets the limit pointer LP to a value that can receive only 1 byte.
Then, as in S20 and thereafter, when the write DMA controller 34 writes 1-byte data to the RAM 33,
Immediately, the CPU 31 reads this and interprets the command, and the next 1-byte data is written in the RAM 33 so as to overwrite this data.

For example, when the command is the data number setting command again, S50 = NO and S60 = YES, and the image data is written in the RAM 33 so as to overwrite the command data again. And S50 = Y
When it becomes ES, one page of image data is stored in the RAM 33 without leaving command data in between.
It becomes the state written in. As a result, the read DMA
The controller 35 can read the image data from the RAM 33 in order and execute printing.

Next, a second embodiment will be described. This printer system is also the same as that shown in FIG. 1 as a whole. However, the controller unit 130 of the printer has a slightly different configuration. It is configured as shown in FIG. 5, and includes CPU 131, ROM 132, RAM 13
3, write DMA controller 134, read DMA controller 135, receiving unit 136, write pointer management unit 137, read pointer management unit 138, decoder 13
9, a line shift buffer 140 and a first comparator 142 are provided as in the first embodiment. As a configuration peculiar to the second embodiment, instead of the limit pointer,
The point is that a data number counter 151 that receives an increment signal from the reception unit 136 and counts down is provided. This data number counter 151 is
The counter value is set by 31 and a High level signal is generated when the counter value becomes 0 by the countdown. The output of the data number counter 151 is input to the OR circuit 145 together with the output of the first comparator 142, and the receiving unit 136 and the Ac are output.
It is input to the k generation unit 146. Further, the output of the data number counter 151 is sent to the CPU 1 via the inverter 147.
It is designed to be input to 31 interrupt terminals. In addition,
Also in this embodiment, the elements other than the CPU, ROM, and RAM are configured by ASIC.

Next, the contents of processing by the CPU 131 of the second embodiment will be described. As shown in FIG. 6, the CPU 31 first sets the write pointer WP, the read pointer RP, and the counter CT to WP = 0, RP = 0, CT =, respectively.
It is initialized to 1 (S210). This allows writing DM
The A controller 134 can write only one byte of data in the RAM 133. RAM 13
When 1 byte of data is written in 3, CT = 0 and an interrupt occurs. In response to the occurrence of this interrupt,
The CPU 131 reads the data written at the address of WP-1, decrements WP ← WP-1 and the write pointer, and executes command interpretation of the data that was just read (S220 to S250).

As a result of this command interpretation, the form feed "

If "F" is designated (S260 = YE)
S), after starting the engine unit 141 and confirming the sheet position by the sensor of the engine unit 141, read DM
A start command is output to the A controller 135 (S270
~ S290).

On the other hand, when the form feed is not instructed, the data number setting command "

It is determined whether "G ***" has been received (S300). If the command is not the data number setting command, the processing from S220 onward is executed again, but if it is the data number setting command, the number of bytes of the data instructed by the command is set in the counter CT (S310), and then the interrupt signal It waits until is entered (S320). When the interrupt signal is input, the counter CT is set to the byte number 1 and the process returns to S220 (S330).

Through the above processing, the write DMA controller 134 performs the same operation as that of the first embodiment, and RA of the image data for one page does not leave command data in between.
The state is written in M133. As a result, the read DMA controller 135 can read the image data from the RAM 133 in order and execute printing.

Next, a third embodiment will be described. Third
The embodiment is configured to transmit print data using both the compatible mode and ECP mode of the IEEE1284 standard. First, a method of transmitting data will be described.

The data structure itself is the same as that shown in FIG. As shown in FIG. 7, this data transmits only command data in the compatible mode, and the EC
Image data is transmitted in the forward phase after the P mode negotiation phase and the setup phase are completed. In addition, IEEE128
According to the four standards, the compatible mode is set when the 1284 Active signal is at low level, and the ECP mode is set when it is at high level. Compatible mode and ECP
The difference between the modes is in the way of the shake hand. Specifically, it has been explained in the section of the prior art, so please refer to it.

The printer system of the third embodiment is constructed as shown in FIG.
30 is a CPU 231, a ROM 232, a RAM 233,
A write DMA controller 234, a read DMA controller 235, a decoder 235a, and a line shift buffer 236 are provided.

In the third embodiment, the CPU 231 is also connected to the Centronics cable interface 238 via the data bus 237. In addition, CPU
A latch 239 is provided between 231 and the interface 238. Further, the CPU 231 and the write DMA
The strobe signal line 241 is connected to the controller 234, and the other control line 242 is further connected to the CPU 231.

Next, the processing contents of the CPU 231 of the third embodiment will be described. The CPU 231 is, as shown in FIG.
The command interpretation is executed after receiving only 1 byte of data, and the data number setting command “

It is judged whether or not it is "G ***" (S410-S410).
S430). During this period, since the stop signal from the CPU 231 is input to the write DMA controller 234 (S405), no data is written to the RAM 233.

If the command is not the data number setting command, the process according to the command interpretation result is executed (S440).
If the command is a data number setting command, the set data number N is stored (S450). And CPU2
In the other control line 242, 31 is 1284Acti
It is determined whether or not the signal on the control line outputting ve has become High level, and the process waits until it becomes High level (S460).

When 1284 Active becomes High level, negotiation and setup processing for entering the ECP mode is executed (S470, S48).
0). As a result, the forward phase of the ECP mode is entered. In the forward phase, the write DMA controller 234 is instructed to start and the latch 239 is released (S490). As a result,
All data transmitted thereafter will be written in the RAM 233 via the write DMA controller 234.

Then, of the other control lines 242, it is determined whether or not the signal of the control line outputting 1284 Active has become Low level, and the process waits until it becomes Low level (S500). 1284Activ
When e becomes Low level, the write DMA controller 234 is instructed to stop and the latch 239 is enabled (S510). As a result, the data transmitted thereafter will not be written in the RAM 233 and will be all received by the CPU 231.

After that, the CPU 231 executes the termination phase for returning from the ECP mode to the compatible mode (S520). Then, it is determined whether or not the number of bytes DN of the data received so far matches the number N stored in S450 (S53).
0), if they do not match, it is determined whether DN <N (S540). If YES is determined in S540, the process returns to S460. However, if NO in S540, an error is notified and the process ends (S5).
50). When DN = N, the 1-byte receiving state in the compatible mode is returned to and the command interpretation is executed. Then, if there is a data number setting command again, the processing from S450 onward is repeated, and if it is a form feed command, the read DMA controller 235 is activated to start printing.

In this way, also in the third embodiment, the write DMA controller 234 does not leave command data between image data for one page and the RAM 233.
It becomes the state written in. As a result, the read DMA
The controller 235 can read image data from the RAM 233 in order and execute printing.

Next, a fourth embodiment will be described. 4th
The embodiment is configured to transmit the command data for printing and the image data in the forward phase of the ECP mode of the IEEE1284 standard. First, a method of transmitting data will be described.

The data structure itself is the same as that shown in FIG. As shown in FIG. 10, this data is output according to the rule that, in the case of command data, HostAck is set to Low, and in the case of image data, HostAck is set to High. That is, as shown in FIG. 11, when the data to be output is command data (S610 = YES), the host outputs the command data to the 8-bit data line and sets HostAck to L.
If it is the ow level (S620, S630) and if it is image data (S610 = NO), the image data is output to the data line and the HostAck is set to the High level (S640, S650). And then, H
Set ostClk to Low to notify the printer side that the data set is complete (S660).
Wait for Ack = High to return (S670).
Then, when PeriphAck = High, immediately return to HostClk = High, and at the same time Perip
Wait for hAck = Low to return (S680, S
690). When PeriphAck = Low is returned, the process returns to S610 to immediately execute the process of setting the next output data in the data line. S6 during this time
The shake hand method of 60 to S690 is unique to the ECP mode.

The printer system of the fourth embodiment has the same structure as that of the third embodiment, but is particularly characterized by the method of connecting the strobe signal line and the like. See Figure 1 for details.
2, the data bus 337 that outputs 8-bit data is input to the write DMA controller 334 and the latch 339. The data bus 337 is further connected from the latch 339 to the CPU 331.

In addition, the strobe signal line HostC
The lk line 351 is a monostable flip-flop 352.
Is connected so that the falling signal is detected. Then, the output of the monostable flip-flop 352 is input to the OR circuit 355 together with the inverted signal from the inverter 354 of the HostAck line 353, and is input to the write DMA controller 334. The signal from the OR circuit 355 is the write DMA controller 33.
4 and the write DMA controller 334 only when the operation signal becomes Low level.
Is supposed to work. Specifically, HostC
Low signal at the falling edge of lk and HostAck = Hi
The write DMA controller 334 operates only when gh overlaps.

The output of the monostable flip-flop 352 is
Further, it is input to the second OR circuit 358 together with the inverted signal from the inverter 357 of the 1284 Active line 356. The output of the second OR circuit 358 is output to the third output together with the signal of the HostAck line 353.
Is input to the OR circuit 359. Third OR circuit 3
The output of 59 is input to the latch 339 and the CPU 331.

As for the relationship between this signal and the operation of the CPU 331, 1284Active = High, H
Only when ostClk = Low and HostAck = Low, the Low interrupt signal is input to the CPU 331 and the latch 339. Therefore, the CPU 33
1 is 1284Active = High, HostCl
Only when k = Low and HostAck = Low, the data is received and the command interpretation is executed.

By the way, as described at the beginning, in the fourth embodiment, in the forward phase of the ECP mode,
Since the command data is output with HostAck = Low and the image data is output with HostAck = High, as a result of the above configuration, the write DMA controller 334 receives only the image data and writes it in the RAM 333, and the command data Will be interpreted and processed by the CPU 331 without being written to the RAM 333.

As a result, also in the fourth embodiment, the write DMA controller 334 does not leave command data in the image data for one page and the RAM 333 does not have the command data in between.
It becomes the state written in. As described above, in each embodiment, at least the image data is transmitted in the ECP mode, so that the data can be transferred at a much higher speed than in the conventional Centronics mode.
The effects of the DMA controller can be fully demonstrated. Moreover, in any of the embodiments, RA is used when printing is executed.
Since image data for one page is arranged in order in M without any intervening command data, it can be processed at high speed by the read DMA controller. As a result, high-speed printing, which is an advantage of the host-based printer system, can be achieved more significantly. That is, as a special effect of the host-based printer system, it does not require time to develop the image data, realizes high-speed transfer as an effect peculiar to the ECP mode, and realizes high-speed reception by the DMA controller as well as command data. Since the image data is properly distinguished and processed, it is possible to achieve remarkably high speed as a synergistic effect of these.

Although some embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and it is needless to say that the present invention can be implemented in various modes without departing from the scope of the invention. Is. For example, in the EPP mode which is basically the same as the shake hand system except that the use of the signal line is different, it is needless to say that the same effect can be exerted by adopting the same configuration as the above embodiment.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a host-based printer system according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating a structure of print data and a transmission method according to the first embodiment.

FIG. 3 is a block diagram showing a configuration of a control unit of the printer in the first embodiment.

FIG. 4 is a flowchart showing processing contents of reception control of a printer CPU in the first embodiment.

FIG. 5 is a block diagram showing a configuration of a control unit of the printer in the second embodiment.

FIG. 6 is a flowchart showing the processing contents of reception control of the printer-side CPU in the second embodiment.

FIG. 7 is an explanatory diagram showing a method of transmitting print data according to the third embodiment.

FIG. 8 is a block diagram showing a configuration of a control unit of a printer according to a third embodiment.

FIG. 9 is a flowchart showing the processing content of reception control of the printer CPU in the third embodiment.

FIG. 10 is an explanatory diagram showing a method of transmitting print data according to the fourth embodiment.

FIG. 11 is a flowchart showing the processing contents of transmission control of the host CPU in the fourth embodiment.

FIG. 12 is a block diagram showing a configuration of a control unit of a printer according to a fourth embodiment.

[Explanation of symbols]

1 ... Printer system, 2 ... Print host, 3 ...
..Laser printer, 4 ... Centronics cable, 31 ... CPU, 32 ... ROM, 33 ...
RAM, 34 ... Write DMA controller, 35 ...
..Reading DMA controller, 36 ... Receiving unit, 3
7 ... Write pointer management unit, 38 ... Read pointer management unit, 39 ... Decoder, 40 ... Line shift buffer, 41 ... Engine unit, 42 ... First
Comparator, 43 ... Limit pointer management unit,
44 ... second comparator, 45 ... OR circuit,
46 ... Ack generation unit, 47 ... Inverter, 13
1 ... CPU, 132 ... ROM, 133 ... R
AM, 134 ... Write DMA controller, 135
... Read DMA controller, 136 ... Receiving unit, 137 ... Write pointer management unit, 138 ...
Read pointer management unit, 139 ... Decoder, 142
... First comparator, 146 ... Ack generator, 147 ... Inverter, 151 ... Data number counter, 231 ... CPU, 232 ... ROM, 2
33RAM, 234 ... Write DMA controller,
235 ... Read-out DMA controller, 235a ...
Decoder, 236 ... Line shift buffer, 23
7 ... data bus, 238 ... interface, 2
39 ... Latch, 241 ... Strobe signal line, 2
42 ... Other control lines, 331 ... CPU, 33
2 ... ROM, 333 ... RAM, 334 ... Write DMA controller, 337 ... Data bus, 3
39 ... Latch, 351 ... HostClk line, 352 ... Monostable flip-flop, 353 ...
・ HostAck line, 354 ... Inverter, 3
55 ... First OR circuit, 356 ... Active
Lines, 357 ... Inverters, 358 ... Second OR circuits, 359 ... Third OR circuits.

Claims (11)

[Claims] 1. A host-based printer system in which image data for printing is previously formed on the host side, and the image data and command data for printing are output to a printer for printing, and at least the image data Send and receive, IEEE128
A data transmission / reception means for carrying out the shake hand method in the ECP mode or EPP mode of the four standards is provided, and the printer side has a write DMA controller for receiving the image data and writing it in a reception buffer, and the reception for executing printing. A read DMA controller for reading image data from the buffer, and image data storage means for storing data in the reception buffer so that command data is not interposed between image data for one page. Host based printer system. 2. The host-based printer system according to claim 1, wherein the image data storage unit distinguishes the command data from the image data, and stores the command data between the image data and the image data in a reception buffer. A host-based printer system, characterized in that the host-based printer system is configured as means for accumulating data in a reception buffer so as not to leave it. 3. The host-based printer system according to claim 2, wherein the data transmitting / receiving unit is a unit for performing transmission / reception of command data and image data for printing by a shake hand system of ECP mode or EPP mode of IEEE1284 standard. At the same time, the receiving state of the writing DMA controller on the printer side is switched between a 1-byte receiving state in which it temporarily stops after receiving 1-byte data and a continuous receiving state in which it continuously receives data. The switching means and the condition for switching the reception state by the reception state switching means based on the interpretation result by reading and interpreting the data written in the reception buffer by the write DMA controller in the 1-byte reception state. The switching condition setting means for setting the When you start to write data, the host-based printer system characterized by configuring the image data writing means by causing a overwriting means going overwritten on the data written in the 1-byte receiving state. 4. The host-based printer system according to claim 3, wherein the reception state switching means is composed of a limit pointer for giving a write pointer stop condition by the write DMA controller, and the switching condition setting means By setting a pointer next to the current write pointer to the limit pointer, a 1-byte reception state is set, and by setting a pointer ahead by the number of bytes of the image data found as a result of command interpretation to the limit pointer, continuous A host-based printer system, wherein the host-based printer system is configured as means for setting a reception state, and the overwriting means is configured as means for performing the overwriting by returning a write pointer. 5. The host-based printer system according to claim 3, wherein the reception state switching means is composed of a counter for giving a movement amount of a write pointer by the write DMA controller, and the switching condition setting means is The counter is set to a 1-byte reception state by setting the number of bytes 1, and the counter is configured to set a continuous reception state by setting the number of bytes of image data found as a result of command interpretation. A host-based printer system, characterized in that the means is configured as means for performing the overwrite by returning a write pointer. 6. The host-based printer system according to claim 4 or 5, wherein the write pointer is returned to the immediately preceding state after the switching condition setting means has read the data in the 1-byte reception state. And host-based printer system. 7. The host-based printer system according to claim 2, wherein the data transmitting / receiving unit is a unit for performing transmission / reception of command data and image data for printing by a shake hand system of ECP mode or EPP mode of IEEE1284 standard. At the same time, the host side is provided with an identification signal output means for distinguishing when the command data is being output and when the image data is being output, and on the printer side, the identification signal is command data. While it means the output of, the write DMA controller is stopped and the command data is received and interpreted by itself.
A host characterized in that the image data writing means is configured by providing a central processing unit for causing the write DMA controller to receive image data while the identification signal means output of image data. Base printer system. 8. The host-based printer system according to claim 2, wherein the data transmission / reception unit is configured to transmit / receive image data by IEEE
The E1284 standard ECP mode or EPP mode shake hand method is used to send and receive command data.
The printer is configured as a means for performing a shake hand method in the compatible mode of the EE1284 standard, and the command data transmitted under the compatible mode is directly received and interpreted by the printer side.
By providing a central processing unit that causes the write DMA controller to receive the data transmitted until the termination phase is started after the completion of the setup phase in the CP mode or the EPP mode, the image data is provided. A host-based printer system comprising a writing unit. 9. A data transmission / reception method in a host-based printer system, wherein image data for printing is formed in advance on the host side, and the image data and command data for printing are output to a printer for printing. Command data and image data for IEEE 12
A data transmission / reception method in a host-based printer system, characterized in that the data is transmitted / received by a shake hand system of ECP mode or EPP mode of 84 standard. 10. A data transmitting / receiving method in a host-based printer system, wherein image data for printing is formed in advance on the host side, and the image data and command data for printing are output to a printer for printing. Command data and image data for IEEE 12
In addition to transmitting and receiving in the 84-standard ECP mode or EPP mode shake hand system, an inversion signal that is inverted when the command data is output and when the image data is output is also output from the host side. A data transmission / reception method in a host-based printer system characterized. 11. A data transmission / reception method in a host-based printer system, wherein image data for printing is formed in advance on the host side, and the image data and command data for printing are output to a printer for printing. A data transmission / reception method in a host-based printer system, characterized in that data transmission / reception is performed by an ECP mode or EPP mode shake hand system of IEEE1284 standard, and command data transmission / reception is performed by a compatible mode shake hand system of IEEE1284 standard.