Rust LILYGO T-Display with RP2040
1. Hardware
- LILYGO T-Display RP2040 (https://www.lilygo.cc/products/t-display-rp2040)
LILYGO makes nice hardware modules that combine various TFT LCD displays with popular MCUs, such as ESP32 and RP2040.
About two years ago, it introduced this T-display module that combines RP2040 (Raspberry Pi PICO) MCU with a ST7789V controlled 1.14" LCD display (135 x 240 pixels).
Here are snippets from its schematic showing the signals between RP2040 MCU and ST7789V (its datasheet) display controller.
Note that ST7789V itself supports a number of physical layer data protocols (3-line serial, 4-line serial, parallel data bits etc.) The T-Display module adopts 4-line serial protocol, i.e. in addition to the SPI bus, “TFT_RS” (register select) signal is used to select between COMMAND and DATA of the clocked data bytes. In theory, this “TFT_SPI0_TX” signal line can be bi-directional. But in practice, it’s only used to stream video data from MCU to the display.
Here is another picture of such display controller in a Waveshare LCD hardware module. Notice that the “TFT_RS” signal is named as “DC” (data or command) in this case. And “TFT_LEDK” becomes “BL”, i.e. back light control.
