nucleo64-lcd-st7735

LCD shield for STM32 Nucleo-64 boards.

This shield is designed for connecting to STM32 Nucleo-64 boards via Arduino^TM Uno V3.

WARNING: Although this shield can be connected to the Arduino^TM UNO, it is incompatible in logic levels, so it is strictly forbidden to connect this way, otherwise this display will fail!

Hardware

• The GMT177-01 module is used as a display and is compatible in size and pins. The display controller used is ST7735. The display data bus is connected to the hardware SPI. PWM can be used to control the brightness of the screen backlight.
• Joystick K1-1504SA-03 and one button KLS7-TS6601 can be used for control. Both are connected to 3 General Purpose I/O ports via diodes.
• EEPROM memory M24C08 can be used to store user data. This IC is connected to the I2C hardware bus.
• Two LEDs are connected to ports A0(PA0) and A1(PA1).
• A separate button IT-1187-160GM-G is provided to reset the controller.

Demo firmware

Two versions of the demo firmware have been written to work on the NUCLEO-F446RE and this shield, one using CMSIS, the other using HAL. Both are under BSD-3-Clause License.

• Using CMSIS: nucleo-f446re-st7735spi-shield
• Using HAL: nucleo-f446re-st7735spi-shield-hal

Compare performance

#	bpp variant	fill period, ms	transfer period, CMSIS, ms	transfer period, HAL, ms
1	fb=1, lcd=12	3	23	40
2	fb=1, lcd=16	3	30	60
3	fb=1, lcd=18	3	44	74
4	fb=4, lcd=12	3	23	39
5	fb=4, lcd=16	3	30	58
6	fb=4, lcd=18	3	44	73
7	fb=8, lcd=12	2	23	39
8	fb=8, lcd=16	2	30	59
9	fb=8, lcd=18	2	44	73
10	fb=16, lcd=12	3	22	39
11	fb=16, lcd=16	3	30	59
12	fb=16, lcd=18	3	44	75
13	fb=24, lcd=12	3	22	38
14	fb=24, lcd=16	3	30	61
15	fb=24, lcd=18	3	44	73

Where fb - frame buffer color depth, lcd - LCD module color depth, fill period - frame buffer fill period, transfer period - period of frame buffer transmission to LCD module.

Tests performed at SPI clock 11,25 Mbits/s.

Schematic

Some photo

Unfortunately, there are currently no rev.4 boards, and the existing rev.3 boards have a small error - the LEDs are connected to RX/D0(PA3) and TX/D1(PA2), which by default are connected to the USART of the on-board ST-LINK/V2-1 programmer. To correct this drawback, two wire are placed on the bottom of the board to ports A0(PA0) and A1(PA1). The boards of the rev.4 are free from this drawback.

Front view (rev.3)

Back view (rev.3)

Paired with NUCLEO-F446RE with running demo (rev.3)