Espressif: Use i2s peripheral for parallel LCD displays

[jepler]

This enables non-consecutive pins and higher effective clock rates. It successfully drives the 2.8" TFT LCD in parallel mode (but so did the previous code).

My testing board is an Espressif Kaluga and the code is

import board
import displayio
import paralleldisplay
    
    
_DISPLAY_D0 = board.IO8
_DISPLAY_CS = board.IO2
_DISPLAY_CD = board.IO3  
_DISPLAY_WR = board.IO4
_DISPLAY_RD = board.IO5
_DISPLAY_RESET = board.IO6
_DISPLAY_BACKLIGHT = board.IO7
    
_INIT_SEQUENCE = (
    b"\x01\x80\x80"  # Software reset then delay 0x80 (128ms)
    b"\xEF\x03\x03\x80\x02"
    b"\xCF\x03\x00\xC1\x30"
    b"\xED\x04\x64\x03\x12\x81"
    b"\xE8\x03\x85\x00\x78"
    b"\xCB\x05\x39\x2C\x00\x34\x02"
    b"\xF7\x01\x20"  
    b"\xEA\x02\x00\x00"
    b"\xc0\x01\x23"  # Power control VRH[5:0]
    b"\xc1\x01\x10"  # Power control SAP[2:0];BT[3:0]
    b"\xc5\x02\x3e\x28"  # VCM control
    b"\xc7\x01\x86"  # VCM control2
    b"\x36\x01\x38"  # Memory Access Control
    b"\x37\x01\x00"  # Vertical scroll zero
    b"\x3a\x01\x55"  # COLMOD: Pixel Format Set
    b"\xb1\x02\x00\x18"  # Frame Rate Control (In Normal Mode/Full Colors)
    b"\xb6\x03\x08\x82\x27"  # Display Function Control
    b"\xF2\x01\x00"  # 3Gamma Function Disable
    b"\x26\x01\x01"  # Gamma curve selected
    b"\xe0\x0f\x0F\x31\x2B\x0C\x0E\x08\x4E\xF1\x37\x07\x10\x03\x0E\x09\x00"  # Set Gamma
    b"\xe1\x0f\x00\x0E\x14\x03\x11\x07\x31\xC1\x48\x08\x0F\x0C\x31\x36\x0F"  # Set Gamma
    b"\x11\x80\x78"  # Exit Sleep then delay 0x78 (120ms)
    b"\x29\x80\x78"  # Display on then delay 0x78 (120ms)
)   
    
displayio.release_displays()
    
BUS = paralleldisplay.ParallelBus(data0=_DISPLAY_D0, command=_DISPLAY_CD, chip_select=_DISPLAY_CS, write=_DISPLAY_WR, read=_DISPLAY_RD, reset=_DISPLAY_RESET, frequency=2_500_000)
display = displayio.Display(BUS, init_sequence=_INIT_SEQUENCE, width=320, height=240, backlight_pin=_DISPLAY_BACKLIGHT)

[kmatch98]

Read through the code. Looks like more efficient and clearer use of the i2s peripheral (and esp’s library) to give more flexibility and also add 16 bit parallel LCD.

Good reuse of code for older _construct function.

Did not test on hardware.

[gamblor21]

Tested on an UnexpectedMaker TinyS2 with the Adafruit 480x320 TFT breakout. Could only test non-sequential pins as I did not have 8 pins together, but no issues. Tried a few different display frequencies with no issues. Looked over the code and I saw no issues there.

[jepler]

hah, I forgot I hadn't acually tested non-consecutive pins 🤣 so thanks for that @gamblor21