1. Introduction

The ST7787 is a single-chip controller/driver for 262K-color, graphic type TFT-LCD. It consists of 720 source line and 320 gate line driving circuits. This chip is capable of connecting directly to an external microprocessor, and accepts Serial Peripheral Interface (SPI), 8-bits/9-bits/16-bits/18-bits parallel interface. Display data can be stored in the on-chip display data RAM of 240x320x18 bits. It can perform display data RAM read/write operation with no external operation clock to minimize power consumption. In addition, because of the integrated power supply circuits necessary to drive liquid crystal, it is possible to make a display system with the fewest components.

2. Features

• Single chip TFT-LCD controller/driver with display data RAM

• Display resolution: 240(H) x RGB x 320(V)

• Display data RAM (frame memory): 240 x 320 x 18-bits = 1,382,400 bits

• Operation Frequency: DC~30MHz (30MHz for 6 bits, 10MHz for 18 bits)

• Output:

- 240ch source outputs (240RGB)

- 320ch gate outputs

- Common electrode output

• Display mode (color mode)

- Full color mode (idle mode off): 262K-colors

- Reduce color mode (idle mode on): 8-colors (1-bit for individual R, G, B color depth)

• Display resolution option

- 240 x 320 Display with 240 x 18-bits x 320 display RAM

• Supported LC type option

- MVA LC type (When LCM[1]=0,LCM[0]=0 )

- Transflective LC type (When LCM[1]=0,LCM[0]=1 )

- Transmissive LC type (When LCM[1]=1,LCM[0]=0 )

• Supported data format on display host interface

- 12-bits/pixel: RGB= (444) using the 1382k bits frame memory and LUT

- 16-bits/pixel: RGB= (565) using the 1382k bits frame memory and LUT

- 18-bits/pixel: RGB= (666) using the 1382k bits frame memory

• Supported MCU Interface

- 3-line serial interface

- 8-bits, 9-bits, 16-bits, 18-bits interface with 8080-series MCU

- 8-bits, 9-bits, 16-bits, 18-bits interface with 6800-series MCU

- 6-bits, 16-bits, 18-bits RGB interface with graphic controller

• Display features

- Area scrolling

- Partial display mode

- Software programmable color depth mode

• Build-in circuit

- DC/DC converter

- Adjustable VCOM generation

- Non-volatile (NV) memory to store initial register setting

- Oscillator for display clock generation

- Timing controller

- 4 preset gamma curve for γ=1.0/1.8/2.2/2.5 (supporting Transflective) and 1 preset gamma curve for γ=2.2

(supporting MVA, Ttransmissive type LC)

- Factory default value (contrast, module ID, module version, etc) are stored in NV memory

- Line inversion, frame inversion

• NV Memory

- 8-bits for ID1

- 7-bits for ID2

- 8-bits for ID3

- 8-bits for VCOM adjustment

• Supply voltage range

- Analog supply voltage range (VDD to AGND): 2.45V – 3.3V

- I/O supply voltage range (VDDI to DGND): 1.65V – 3.3V

• Output voltage level

- Source output voltage range (GVDD to AGND): 3.0V to 5.0V

- Power supply range for driver circuit (AVDD to AGND): 5.2V (VDD=2.6V) to 6.0V (VDD=3.0V)

- Output range of HIGH level of VCOM (VCOMH to AGND): 2.5V to 5.0V

- Output range of LOW level of VCOM (VCOML to AGND): -2.5V to 0.0V

- Output range of HIGH level of gate driver (VGH to AGND): +12V to +16.5V

- Output range of LOW level of gate driver (VGL to AGND): -14V to –5V

• Lower power consumption, suitable for battery operated systems

- CMOS compatible inputs

- Optimized layout for COG assembly

- Operate temperature range: -30 to + ℃ 70℃