ILI9488: Add code comments re SPI clock rate.

master
Peter Hinch 2025-06-30 14:41:22 +01:00
rodzic 8fbb4b7474
commit 843d153f8f
2 zmienionych plików z 68 dodań i 50 usunięć

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@ -2,7 +2,7 @@
### Based on ili9486.py by Peter Hinch.
### Retaining his copyright
#
# Copyright (c) Peter Hinch 2022-2025
# Released under the MIT license see LICENSE
@ -15,6 +15,7 @@
# You must use this driver only when using the ILI9488 SPI
# interface. It will send 3 bytes per pixel.
# ILI9488 max SPI baudrate 20MHz (datasheet 17.4.3) but 24MHz is a reasonable overclock.
from time import sleep_ms
import gc
@ -26,21 +27,21 @@ from drivers.boolpalette import BoolPalette
# small performance improvement.
# greyscale
@micropython.viper
def _lcopy_gs(dest: ptr8, source: ptr8, length: int) :
def _lcopy_gs(dest: ptr8, source: ptr8, length: int):
# rgb666 - 18bit/pixel
n: int = length * 6 - 1
while length:
length -= 1
c : uint = source[length]
c: uint = source[length]
# Store the index in the 4 high order bits
p : uint = c & 0xF0 # current pixel
q : uint = c << 4 # next pixel
p: uint = c & 0xF0 # current pixel
q: uint = c << 4 # next pixel
dest[n] = q
n -= 1
dest[n] = q
n -= 1
dest[n] = q
dest[n] = q
n -= 1
dest[n] = p
@ -50,18 +51,19 @@ def _lcopy_gs(dest: ptr8, source: ptr8, length: int) :
dest[n] = p
n -= 1
# Do processing from end to beginning for
# small performance improvement.
# color
@micropython.viper
def _lcopy(dest: ptr8, source: ptr8, lut: ptr16, length: int) :
def _lcopy(dest: ptr8, source: ptr8, lut: ptr16, length: int):
# Convert lut rgb 565 to rgb666
n: int = length * 6 - 1
n: int = length * 6 - 1
while length:
length -= 1
c : uint = source[length]
c: uint = source[length]
v = lut[c & 0x0F] # next pixel
v = lut[c & 0x0F] # next pixel
dest[n] = (v & 0x001F) << 3 # B
n -= 1
dest[n] = (v & 0x07E0) >> 3 # G
@ -69,7 +71,7 @@ def _lcopy(dest: ptr8, source: ptr8, lut: ptr16, length: int) :
dest[n] = (v & 0xF800) >> 8 # R
n -= 1
v : uint = lut[c >> 4] # current pixel
v: uint = lut[c >> 4] # current pixel
dest[n] = (v & 0x001F) << 3 # B
n -= 1
dest[n] = (v & 0x07E0) >> 3 # G
@ -77,6 +79,7 @@ def _lcopy(dest: ptr8, source: ptr8, lut: ptr16, length: int) :
dest[n] = (v & 0xF800) >> 8 # R
n -= 1
class ILI9488(framebuf.FrameBuffer):
lut = bytearray(32)
@ -91,8 +94,17 @@ class ILI9488(framebuf.FrameBuffer):
# Transpose width & height for landscape mode
def __init__(
self, spi, cs, dc, rst, height=320, width=480, usd=False, mirror=False, init_spi=False,
lines_per_write=4
self,
spi,
cs,
dc,
rst,
height=320,
width=480,
usd=False,
mirror=False,
init_spi=False,
lines_per_write=4,
):
self._spi = spi
self._cs = cs
@ -108,14 +120,14 @@ class ILI9488(framebuf.FrameBuffer):
#
# lines_per_write must divide evenly into height
#
if (self.height % lines_per_write) != 0 :
raise ValueError('lines_per_write invalid')
self._lines_per_write=lines_per_write
if (self.height % lines_per_write) != 0:
raise ValueError("lines_per_write invalid")
self._lines_per_write = lines_per_write
gc.collect()
buf = bytearray(height * width // 2)
self.mvb = memoryview(buf)
super().__init__(buf, width, height, self.mode) # Logical aspect ratio
self._linebuf = bytearray(self._lines_per_write*self.width * 3)
self._linebuf = bytearray(self._lines_per_write * self.width * 3)
# Hardware reset
self._rst(0)
@ -136,14 +148,14 @@ class ILI9488(framebuf.FrameBuffer):
self._wcd(b"\x2a", int.to_bytes(self.width - 1, 4, "big"))
self._wcd(b"\x2b", int.to_bytes(self.height - 1, 4, "big")) # SET_PAGE ht
if self.width > self.height :
if self.width > self.height:
# landscape
madctl = 0xe8 if usd else 0x28
else :
#portrait
madctl = 0xE8 if usd else 0x28
else:
# portrait
madctl = 0x48 if usd else 0x88
if mirror:
madctl ^= 0x80 # toggle MY
madctl ^= 0x80 # toggle MY
self._wcd(b"\x36", madctl.to_bytes(1, "big")) # MADCTL: RGB portrait mode
self._wcmd(b"\x11") # sleep out
self._wcmd(b"\x29") # display on
@ -184,18 +196,18 @@ class ILI9488(framebuf.FrameBuffer):
wd = self.width >> 1
ht = self.height
spi_write = self._spi.write
length = self._lines_per_write*wd
length = self._lines_per_write * wd
r = range(0, wd * ht, length)
if cm :
lcopy = _lcopy_gs # Copy greyscale
for start in r : # For each line
lcopy(lb, buf[start:], length)
if cm:
lcopy = _lcopy_gs # Copy greyscale
for start in r: # For each line
lcopy(lb, buf[start:], length)
spi_write(lb)
else :
else:
clut = ILI9488.lut
lcopy = _lcopy # Copy and map colors
for start in r : # For each line
lcopy(lb, buf[start:], clut, length)
for start in r: # For each line
lcopy(lb, buf[start:], clut, length)
spi_write(lb)
self._cs(1)
@ -213,8 +225,11 @@ class ILI9488(framebuf.FrameBuffer):
lines, mod = divmod(self.height, split) # Lines per segment
if mod:
raise ValueError("Invalid do_refresh arg 'split'")
if lines % self._lines_per_write != 0 :
raise ValueError("Invalid do_refresh arg 'split' for lines_per_write of %d" %(self._lines_per_write))
if lines % self._lines_per_write != 0:
raise ValueError(
"Invalid do_refresh arg 'split' for lines_per_write of %d"
% (self._lines_per_write)
)
clut = ILI9488.lut
lb = self._linebuf
buf = self.mvb
@ -224,7 +239,7 @@ class ILI9488(framebuf.FrameBuffer):
wd = self.width // 2
line = 0
spi_write = self._spi.write
length = self._lines_per_write*wd
length = self._lines_per_write * wd
for _ in range(split): # For each segment
async with elock:
if self._spi_init: # A callback was passed
@ -232,14 +247,14 @@ class ILI9488(framebuf.FrameBuffer):
self._cs(0)
r = range(wd * line, wd * (line + lines), length)
if cm:
lcopy = _lcopy_gs # Copy and greyscale
for start in r :
lcopy(lb, buf[start:], length)
lcopy = _lcopy_gs # Copy and greyscale
for start in r:
lcopy(lb, buf[start:], length)
spi_write(lb)
else :
lcopy = _lcopy # Copy and map colors
for start in r :
lcopy(lb, buf[start:], clut, length)
else:
lcopy = _lcopy # Copy and map colors
for start in r:
lcopy(lb, buf[start:], clut, length)
spi_write(lb)
line += lines

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@ -8,16 +8,16 @@ from micropython import const
# Modify these Pin assignments to match your hardware.
# Simple GPIO's
LCD_DC = const(21) # PICO Pin 27
LCD_RST = const(22) # PICO Pin 29
LCD_CS = const(27) # PICO Pin 32
LCD_DC = const(21) # PICO Pin 27
LCD_RST = const(22) # PICO Pin 29
LCD_CS = const(27) # PICO Pin 32
LCD_BackLight = const(28) # PICO Pin 34
# SPI pins
LCD_CLK = const(18) # PICO Pin 24
LCD_MOSI = const(19) # PICO Pin 25
LCD_MISO = const(16) # PICO Pin 21
LCD_CLK = const(18) # PICO Pin 24
LCD_MOSI = const(19) # PICO Pin 25
LCD_MISO = const(16) # PICO Pin 21
from machine import Pin, SPI
from drivers.ili94xx.ili9488 import ILI9488 as SSD
@ -26,14 +26,17 @@ from drivers.ili94xx.ili9488 import ILI9488 as SSD
# (Create and export an SSD instance)
prst = Pin(LCD_RST, Pin.OUT, value=1)
pdc = Pin(LCD_DC, Pin.OUT, value=1)
pcs = Pin(LCD_CS, Pin.OUT, value=1)
pdc = Pin(LCD_DC, Pin.OUT, value=1)
pcs = Pin(LCD_CS, Pin.OUT, value=1)
# turn on back light
backlight=Pin(LCD_BackLight, Pin.OUT, value=1)
backlight = Pin(LCD_BackLight, Pin.OUT, value=1)
# Use SPI bus 0, 24 Mhz is maximum speed on PICO
spi = SPI(0, 24_000_000, sck=Pin(LCD_CLK), mosi=Pin(LCD_MOSI, Pin.OUT), miso=Pin(LCD_MISO, Pin.OUT))
# This is an overclock of the ILI9488 - see driver code comment.
spi = SPI(
0, 24_000_000, sck=Pin(LCD_CLK), mosi=Pin(LCD_MOSI, Pin.OUT), miso=Pin(LCD_MISO, Pin.OUT)
)
# Precaution before instantiating framebuf
ssd = SSD(spi, height=480, width=320, dc=pdc, cs=pcs, rst=prst, usd=False)