TWI505247B - Alignment system and method for a display serial interface - Google Patents

Description

Calibration system and method for display serial interface

The present invention relates to a display serial interface (DSI), and more particularly to a calibration system and method for a display serial interface.

The Display Serial Interface (DSI) is a specification developed by the Mobile Industry Processor Interface (MIPI) Alliance to reduce the cost of a display (eg, liquid crystal display) system for mobile devices. The DSI specification primarily defines a serial bus and communication protocol between a host (eg, an image source) and a display module (eg, an image terminal).

The DSI specification uses a turnaround mechanism to dynamically change the direction of transmission between the host and the display module to reduce the cost of the display system of the mobile device.

However, some of the periodic parameters of the host and the display module are usually quite different, causing the host and the display module to fail to work normally during the handshaking, thereby making communication errors and failing to read the data correctly.

Therefore, it is urgent to propose a novel mechanism for the display module to be synchronized with the host to facilitate accurate communication between the host and the display module.

In view of the above, the embodiment of the present invention provides a display serial interface (DSI) calibration system and method for synchronizing the length of the low power mode period TLPX of the display module to the length of the low power mode period TLPX of the host. The handshaking work can work normally to achieve a turnaround of the direction of the transfer.

According to an embodiment of the invention, a calibration system for a display serial interface includes a display module, a serial bus, and a host. The display module includes a driving circuit, and the host transmits commands and data through the serial bus and the display module. The driving circuit detects the length of the low power mode period of the host, so that the length of the low power mode period of the display module is synchronized with the length of the low power mode period of the host.

100‧‧‧ calibration system

11‧‧‧Host

12‧‧‧Display module

121‧‧‧Drive circuit

1211‧‧‧Signal Judgment Circuit

1212‧‧‧ counter

1213‧‧‧ register

122‧‧‧ display

13‧‧‧Sliced bus

21~26‧‧‧Steps for calibration method

TLPX‧‧‧Low Power Mode Cycle

Data0‧‧‧Differential data signal pair

Data0_P‧‧‧First data signal

Data0_N‧‧‧Second data signal

Count‧‧‧count value

The first figure shows a block diagram of a display serial interface (DSI) calibration system in accordance with an embodiment of the present invention.

The second figure shows a flow chart of a calibration method of the display serial interface (DSI) of the embodiment of the present invention.

The third figure illustrates a timing chart of the related signals of this embodiment.

The first figure shows a block diagram of a display serial interface (DSI) calibration system 100 in accordance with an embodiment of the present invention. Although the present embodiment is exemplified by a Display Serial Interface (DSI) developed by the Mobile Industry Processor Interface (MIPI) Alliance, the present invention is also applicable to other similar display serial interfaces. In this embodiment, the host 11 and the client module 12 are connected by the serial bus 13 To send orders and information. The host 11 is used as an image source, and the display module 12 (for example, a liquid crystal display module) is used as an image terminal.

The serial bus 13 mainly includes a clock channel and at least one data channel. Each data channel consists of two wires, using differential signaling. When multiple data channels are used, multiple data transfers can be performed simultaneously, thereby increasing the transfer speed. According to the DSI communication protocol, in addition to at least one channel (e.g., channel 0) having a turnaround mode, the transfer direction is allowed to be changed, and the transfer directions of the remaining channels are all transmitted from the host 11 to the display module 12. The DSI specification defines low power (LP) mode and high speed (HS) mode. In the low power mode, the command transmission and system configuration are mainly performed; in the high speed mode, the data is mainly transmitted.

The display module 12 of the present embodiment mainly includes a driving circuit 121 (for example, a driving integrated circuit) and a display 122 (for example, a liquid crystal display). The driving circuit 121 is electrically coupled to the host 11 through the serial bus bar 13; the driving circuit 121 is configured to drive the display 122 for displaying the image on the display 122. According to one of the features of the embodiment, the driving circuit 121 can detect the length of the low power mode period TLPX of the host 11 so that the length of the low power mode period TLPX of the display module 12 is synchronized with the low power mode of the host 11. The length of the period TLPX.

In this embodiment, the driving circuit 121 includes a signal determining circuit 1211 that can detect the start and end of the low power mode period TLPX of the host 11. The driving circuit 121 further includes a counter 1212 that counts according to the start and end of the low power mode period TLPX detected by the determining circuit 1211 to obtain the length of the low power mode period TLPX of the host 11. The driver circuit 121 further includes a register 1213, such as an internal register, for storing the length of the low power mode period TLPX obtained by the counter 1212 as the length of the low power mode period TIPX of the display module 12. Thereby, the display module 12 The length of the low power mode period TLPX is synchronized with the length of the low power mode period TLPX of the host 11, so that when the host 11 and the display module 12 perform a turnaround in the transmission direction, the handshake agreement can be performed normally. Work to ensure that the entire calibration system 100 is able to communicate correctly to read the data.

The second figure shows a flow chart of a calibration method of a display serial interface (DSI) according to an embodiment of the present invention, and the third figure illustrates a timing chart of related signals. In step 21, when the drive circuit 121 receives the read request, it determines the differential data signal pair Data0 output by the host 11, such as the first data signal Data0_P and the second data signal Data0_N shown in the third figure. When the first data signal Data0_P and the second data signal Data0_N are both high ("1") (or first level) (step 22), the count value (Count) is reset to zero (step 23). Next, in step 24, when the second data signal Data0_N changes from a high level to a low level ("0") (or a second level) and the first data signal Data0_P does not change the level, as shown in the third figure. At time t1, the count value Count is accumulated (step 25). The count value Count will continue to accumulate until the first data signal Data0_P and the second data signal Data0_N become low level (step 26), as shown in the third figure at time t2. Thereby, the length of the low power mode period TLPX of the host 11 can be obtained as the length of the low power mode period TLPX of the display module 12, so that the two can be synchronized. In general, the length of the true low power mode period TLPX can be obtained by multiplying the count value Count by the clock period.

In the third figure, the dashed line indicates the length of the low power mode period TLPX of the display module 12 that does not use the calibration method of the present embodiment. After the calibration method of the embodiment is used, the length of the low power mode period TLPX of the display module 12 can be approximately equal to the length of the low power mode period TLPX of the host 11, and therefore, when the host 11 and the display module 12 are in the transmission direction When turning around, you can The handshaking work is normally performed to ensure that the entire system 100 can communicate correctly to read the data.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; all other equivalent changes or modifications which are not departing from the spirit of the invention should be included in the following Within the scope of the patent application.

100‧‧‧ calibration system

11‧‧‧Host

12‧‧‧Display module

121‧‧‧Drive circuit

1211‧‧‧Signal Judgment Circuit

1212‧‧‧ counter

1213‧‧‧ register

122‧‧‧ display

13‧‧‧Sliced bus

Data0‧‧‧Differential data signal pair

Claims (16)

A calibration system for a serial interface of a display, comprising: a display module comprising a driving circuit; a serial bus; and a host, wherein the serial bus and the display module transmit commands and data; The driving circuit detects the length of the low power mode period of the host, so that the length of the low power mode period of the display module is synchronized with the length of the low power mode period of the host. A calibration system for a display serial interface according to claim 1, wherein the display serial interface is defined by a Mobile Industry Processor Interface (MIPI) Alliance. The calibration system of the display serial interface of claim 1, wherein the serial bus includes at least one data channel having a turnaround mode that allows the transfer direction to be changed. The calibration system of the display serial interface according to claim 1, wherein the display module further comprises a display driven by the driving circuit for displaying an image on the display. The calibration system of the display serial interface according to claim 1, wherein the driving circuit comprises: a signal determining circuit that detects a start and an end of a low power mode period of the host; and a counter according to the counter The start and end of the low power mode period detected by the determining circuit are counted to obtain the length of the low power mode period of the host. The calibration system of the display serial interface according to claim 5, wherein the driving circuit further comprises a temporary register for storing the length of the low power mode period obtained by the counter, as the display module The length of the low power mode period. The calibration system of the display serial interface according to claim 1, wherein the driving circuit performs the following steps: when receiving the read request, determining a differential data signal pair output by the host, which includes the first data a signal and a second data signal; when the first data signal and the second data signal are both at the first level, the count value is reset to zero; when the second data signal is changed from the first level to the second level If the first data signal does not change the level, the count value is accumulated; and the count value is continuously accumulated until the first data signal and the second data signal become the second level. A calibration system for a display serial interface according to claim 7 wherein the drive circuit further performs the step of: multiplying the count value by a clock period to obtain a true low power mode period length. A method for calibrating a serial interface of a display, comprising: providing a serial bus for transmitting commands and data to a host and a display module; and detecting to obtain a length of a low power mode period of the host, so that the display module The length of the low power mode period is synchronized to the length of the low power mode period of the host. The method of calibrating a display serial interface according to claim 9, wherein the display serial interface is defined by a Mobile Industry Processor Interface (MIPI) Alliance. The method of calibrating a display serial interface according to claim 9, wherein the serial bus includes at least one data channel having a turnaround mode, allowing the transfer direction to be changed. The method for calibrating a display serial interface according to claim 9, wherein the display module comprises a display that is driven to display an image on the display. According to the calibration method of the display serial interface according to claim 9, wherein the display module performs the following steps: detecting the start and end of the low power mode period of the host; and according to the detected low power mode The start and end of the cycle are counted to obtain the length of the low power mode period of the host. The method for calibrating a display serial interface according to claim 13 , wherein the display module further performs the following steps: storing the length of the obtained low power mode period as a low power mode period of the display module length. According to the calibration method of the display serial interface according to claim 9, wherein the display module performs the following steps: when receiving the read request, determining the differential data signal pair output by the host, which includes the first The data signal and the second data signal; when the first data signal and the second data signal are both at the first level, the count value is reset to zero; when the second data signal is changed from the first level to the second level And the first data signal does not change the level, the count value is accumulated; and the count value is continuously accumulated until the first data signal and the second data signal become the second level. The calibration method of the display serial interface according to claim 15 , wherein the display module further performs the following steps: multiplying the count value by a clock period to obtain a length of a true low power mode period.