I’ve been working with a custom TFT driver for the ST7789V IPS TFT (320x240 res.) and it’s been smooth-sailing until I upgraded to firmware 3.8.0. At the moment the TFT should initialize, the IDE’s framebuffer view freezes and no image is displayed on the TFT (not even a flicker, actually). I am well aware that there have been significant changes to how TFT’s are handled post 3.6.7, hence my delay in testing the new firmware. However, I am stumped on how that would affect a display directly driven via SPI. I am supplying a bare-minimum set of python code (below) that can drive the display for firmware <= 3.6.7. FYI my actual main application is significantly more complex, however the setup & initialization is identical to the below code. Really hoping I am looking over a mundane detail.
Side Note: I did try using the new LCD driver with the ST7789V, but the image displayed shows signs of incorrect setup and initialization, which I kind of suspected would happen since I am not aware of any official support for this display. Given the changes made to the LCD driver, I’d definitely like to migrate, but my suspicion is that I’d need to modify the firmware to support the ST7789V.
Appreciate any insight!
Note: Code under “ST7789V Driver” should be copied to file system as a file named “ST7789V.py”
Main Python Application:
#TFT screen demo to steam frame buffer to a external SPI screen
#Original Author: Shane Gingell
#Modified to support ST7789V by: Cameron R. MANN (12/2020)
#MIT License (MIT)
import sensor, image, time
from pyb import SPI
from ST7789V import TFT
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames()
clock = time.clock()
spi = SPI(2, SPI.MASTER, baudrate=54000000) #Create SPI bus
#Create instance of the screen driver
#NOTE: CS='P3' & DC='P8' hardcoded in "ST7789V.py"
screen = TFT(spi)
#Set window on screen to write to (x_start, Y_start, width, height),should match frambuffer size
screen.display_setup()
screen.set_window(0,0,320,240)
while(True):
clock.tick()
img = sensor.snapshot()
screen.write_to_screen(img) #send framebuffer to screen
ST7789V Driver:
'''
Copyright (c) 2018 Out of the BOTS
MIT License (MIT)
Original Author: Shane Gingell
Modified to support ST7789V by: Cameron R. MANN (12/2020)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
'''
from pyb import Pin
import time
from ustruct import pack
from micropython import const
class TFT():
_SWRESET = const(0x01) # Software Reset
_SLPOUT = const(0x11) # Sleep Out
_COLMOD = const(0x3A) # Colour Mode
_DISPON = const(0x29) # Display On
_MADCTL = const(0x36) # Memory Data Access
_CASET = const(0x2A) # Column Address Set
_RASET = const(0x2B) # Row Address set
_RAMWR = const(0x2C) #write to screen memory
_INVON = const(0x21) #CRM: inversion on
def send_spi(self,data, is_data):
self.dc.value(is_data) #set data/command pin
self.cs.value(0)
self.hspi.write(data)
self.cs.value(1)
def __init__(self, spi, cs='P3', dc='P8'):
self.hspi = spi
self.cs = Pin(cs, Pin.OUT)
self.dc = Pin(dc, Pin.OUT)
def display_setup(self): #eliminated if here...assuming ST7789V
self.send_spi(bytearray([_SWRESET]), False) #software reset
time.sleep(200)
self.send_spi(bytearray([_SLPOUT]), False) #sleep out
time.sleep(200)
self.send_spi(bytearray([_COLMOD]), False) #set 16 bit colour
self.send_spi(bytearray([0x55]),True)
self.send_spi(bytearray([_DISPON]), False) #display on
self.send_spi(bytearray([_MADCTL]), False) #set mode for writing to screen
self.send_spi(bytearray([0b10110000]),True) #this was the mode that I used for my screen
self.send_spi(bytearray([_CASET]),False) #set x writng window
self.send_spi(pack(">HH", 0, 240), True) #to 0 to 159
self.send_spi(bytearray([_RASET]),False) #set y writing window
self.send_spi(pack(">HH", 0, 320), True) #to 0 to 12
self.send_spi(bytearray([_INVON]),False) #inversion on
def set_window(self, x, y, width, height):
x_end=x+width-1
y_end=y+height-1
self.send_spi(bytearray([_CASET]),False) # set Column addr command
self.send_spi(pack(">HH", x, x_end), True) # x_end
self.send_spi(bytearray([_RASET]),False) # set Row addr command
self.send_spi(pack(">HH", y, y_end), True) # y_end
def write_to_screen(self, data):
self.send_spi(bytearray([_RAMWR]),False) # set to write to RAM
self.send_spi(data, True) # send data