GxTFT library - modifying it to work on other STM32 boards

Using Arduino Displays
23

@RGarrett93,

Version 2.1.2 of library GxTFT is available.

  • added support for my Nucleo-144 proto board with FSMC/FMC TFT connector
  • supported by class GxIO_STM32Nucleo144_P16 using bit-bashing for F767ZI and F746ZG
  • tested with 3.2" ILI9341 on F767ZI
  • FSMC/FMC version will follow, expected to be only slightly faster

My first attempts with FSMC/FMC failed. I will need to take a closer look at the STM32F7 docs.

I have opened an issue about the missing pin #defines for Nucleo-144 F767ZI.

I had to use a workaround to create a long enough write pulse with the bit-bashing verrsion:

  while (num)
  {
    // this doesn't work. reason unknown. optimized by compiler?
    //GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    //GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    //GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    //GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    //GPIOD->BSRR = (0x1 << 5); // PD5 WR high
    // this does work. compiler can't optimize.
    volatile static uint32_t ttt = 1;
    if (ttt++) GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    if (ttt++) GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    //    if (ttt++) GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    //    if (ttt++) GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    //    if (ttt++) GPIOD->BSRR = (0x1 << (5 + 16));  // PD5 WR low
    ttt = 1; // don't miss once in 2**32
    GPIOD->BSRR = (0x1 << 5); // PD5 WR high
    // this would also work, but slower
    //digitalWrite(_wr, LOW);
    //digitalWrite(_wr, HIGH);
    num--;
  }

Jean-Marc