JPS63206852A - Single chip LSI - Google Patents

Abstract

PURPOSE:To enable the content of a program to be rewritten arbitrarily by a user, by providing a pout ROM for storing the program in a single chip LSI. CONSTITUTION:The single chip LSI1 is an LSI for an IC card, and the program for the processing of a CPU6 is stored in an E<2>PROM5, and processes a data inputted via a serial I/O port 3 by using the data stored in an E<2>PROM7, and outputs it to the outside via the port 3. Also, a RAM4 performs the holding of an input data and an output data, etc. The program to write the program on the E<2>PROM5 is stored in the pout ROM2, and also, a procedure to write a new program inputted via the port 3 on the E<2>ROM5, and the procedure the verify a written program are held. Thus, it is possible to rewrite the content of the program arbitrarily.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a single-chip LSI in which a CPU, RAM, ROM, I/O ports, etc. are formed on one chip.
Regarding.

[Conventional technology]

A single-chip LSI includes a CPU, which is an arithmetic unit.

RAM is a writable and readable memory.

A ROM for storing and retaining data, a ROM for storing processing programs, an I10 port for inputting and outputting data with the outside, etc. are mounted on a single chip. Based on the program stored in the program ROM, the CPU inputs the data input through the O port to the RAM and data storage/retention RO.
It operates to process the data stored in M and output the processed data to the outside from the I/O port.

When using a single-chip LSI as described above by incorporating it into a medium such as an IC card, the ROM that stores the CPU processing program is a mask ROM or a rewritable memory such as E''FROM or EPROM, and the data At the stage of writing a processing program for a specific purpose and mounting it on the card board of the IC card using lines or address lines, only the necessary terminals (for example, five terminals) for the IC card are left.

R for programming mounted on LSI mounted on IC card
OM generally cannot be rewritten after it is written in the manufacturing stage and mounted on the IC card, and it cannot be used for other purposes.
If you plan to use a card, use a separately prepared ROM.
Single-chip LSIff equipped with: Must be implemented.

Recently, there has been a desire for users to rewrite the program of commercialized IC cards to suit their own usage, or to change the usage from one usage to another.

Therefore, the above program ROM can be rewritten with R.
Although it seems possible to handle this as an OM, it is not practical to draw out, for example, 8-bit data lines and 16-bit address lines to the card base for rewriting after mounting on an IC card.

Incidentally, since such a single-chip LSI is already known, the literature will not be cited again.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional technology, in order to rewrite a program storage ROM equipped with a single-chip LS IK, it is necessary to provide a data terminal and an address terminal for rewriting, and it is necessary to provide a data terminal and an address terminal for rewriting. In such an LSI, it is not practical to separately provide the above-mentioned terminals in addition to the IC card terminals.

SUMMARY OF THE INVENTION An object of the present invention is to provide a single-chip LSI in which a program storage ROM mounted on the single-chip LSI is a rewritable ROM, and the contents thereof can be arbitrarily rewritten by a user.

[Means for solving problems]

The above purpose is to make the program storage ROM a rewritable ROM, E"FROM, or EPROM, and to make it a single-chip LSI equipped with a 17C ROM that stores a program for rewriting the program,
Serial I/O for inputting the program from outside
This is achieved by providing a port.

[For production]

Since the program rewriting program is built-in, a new program input from the serial I/O port can be stored in the program storage ROM using the program rewriting program, thereby adding new processing functions to the single-chip LSI. Can be granted.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of the present invention, where l is a single-chip LSI, and 2 is a ROM (hereinafter referred to as boot) that stores a program for rewriting the program.
), 3 is a serial I10 port for input/output, 4 is a RAM, 5 is a program storage E-PROM 16 is a CP
U and 7 are E''FROM for data storage and retention.

In the figure, the single-chip LSII is an IC card LSI, and its operation as an IC card is the same as that of the conventional IC card, so a detailed explanation will be omitted.

The Etara FROM 5 stores a program for processing by the CPU 6, and processes the data input via the serial I/O port 3 using the data stored and held in the EtFROM 7. Output to the outside via. Note that the RAM 4 is used to hold input data and output data.

In such a configuration, the boot ROM 2 stores a program for writing a program into the program storage E'FROM 5, and the serial I/O port 3
A procedure for writing a new program input via the CPU 6 into the E''FROM 5 and verifying the written program is held as firmware.

FIG. 2 is a block diagram showing a configuration for writing and rewriting a program transferred from a host computer to E"FROM for program storage, in which 8 is a single-chip LSII path, 9 is a host computer, and FIG. The same symbols correspond to the same parts.

Figure 3 shows E"F for program storage in the configuration of Figure 2.
It is a flowchart explaining the procedure of rewriting the program of ROM.

In FIGS. 2 and 3, the single-chip LSI is connected to a host computer 9 via a serial E/O port 3, and the rewriting program is transferred from the host computer 9.

When the single-chip LSI starts up (step 1), control is transferred to the boot ROM 2 (step 2). Here, initial settings of the serial I/O port 3, initial settings of various parameters, etc. are performed, and data is waited for to be input from the serial I/O port 3. When a program write start signal is received from the host computer 9 via the serial I/O port 3, the CPU 6 reads the data from the serial I/O port 3 (step 3). The CPU 6 determines whether the input data is a program write signal, and if it is determined to be a program write signal, reads the program transferred from the host computer 9 through the serial I10 port 3 (steps 4 and 5). , if it is determined that it is not a program write signal, it is already E”F.
Assuming that the program is written in ROM5, E
``Start the FROM program and communicate with the host computer 9 through the serial I10 port as a normal IC card (steps 4 and 9).

After reading the program in step 5 above, the CPU 6
The program is written in the FROM 5, and whenever program data is sent from the host computer 9, it is written in the FROM 5, verified (step 7), and the result is returned to the host computer 9. Repeat this until the program data transfer is complete.

When the transfer of the program is completed and the writing is completed (step 8), the card communicates with the host computer 9 via the serial I/O port 3 as a normal IC card (step 9).

As described above, the single-chip LSI according to the present invention has a serial I/O port using the well-known R8-23
The program can be easily rewritten via a second grade serial communication line.

The above serial I/O port may be provided with a dedicated port for program rewriting, but in the case of an IC card, if the standard data port is also used, there is no need to provide a dedicated port. The external appearance can be the same as a conventional IC card.

In the above embodiment, E" is used as a ROM for storing programs.
It may be configured to store FROM 5 and E''PRM for data storage/retention. Also, FROM or RAM may be used in place of E'FROM 5 described above.

Also, E"FROM can be rewritten as many times as you like, but after being rewritten once or twice, the boot ROM
It is also possible to prohibit access to the data to prevent it from being illegally rewritten. For ordinary IC cards, it is sufficient to rewrite the program desired by the user to store it at the shipping stage.
This can be achieved by allowing rewriting when the contents of OM are all filled with hexadecimal 'FF' (that is, the first writing), and prohibiting writing in other cases.

The above is an example in which the present invention is applied to an IC card, but parallel I/O ports are used as I/O ports.
For those that are used with the O port installed, either leave the I/O port for data or provide a separate parallel I/O port and rewrite the program by boot R.
It is also possible to perform this using a program stored in OM.

〔Effect of the invention〕

As explained above, according to the present invention, since the single-chip LSI is provided with a boot ROM for storing programs, the program can be easily stored after the single-chip LSI is manufactured or mounted on a medium such as an IC card. Since the design can be modified to meet the user's wishes, it is possible to contribute to shortening the development period and reducing costs, and it is possible to provide a single-chip LSI with excellent functionality.

[Brief explanation of the drawing]

FIG. 1 shows a single-chip LSI showing an embodiment of the present invention.
FIG. 2 is a block diagram showing the configuration for explaining V switching of the program storage ROM, and FIG. 3 is a flow chart explaining the program writing procedure. 1... Single chip LSI, 2... Old boot ROM 3... I/O port, 4...
RAM, 5...EtPROM for program storage
, 6... CPU, 7... Data storage,
・E"FROM for holding. Figure 1 Figure 2

Claims (2)

[Claims] (1) In a single-chip LSI equipped with a CPU, RAM, ROM, and input/output ports, at least the ROM that stores the processing program among the ROMs is a rewritable ROM, and the rewritable ROM is not rewritten. Boot ROM that stores programs to perform
A single-chip LS characterized in that the program data transferred from the input/output port is stored as a program in the rewritable ROM using a program stored in the boot ROM.
I. (2) In the single-chip LSI according to claim (1), a serial I/O port is used as a dedicated port for inputting the rewriting program to the input/output port.
Single chip L featuring /O port
S.I.