PicoPython/SenseHat-1.py at main · bwindrim/PicoPython · GitHub

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from machine import I2C, SoftI2C, Pin
import framebuf
import time
import sys

class SenseHat:
    "Wrapper class for accessing the Sense Hat"

    def __init__(self, i2c_pin_no_clk=3, i2c_pin_no_data=2):
        # ItsyBitsy RP2040 wires its SDA and SCL to GPIO2 and GPIO3 respectively, which are connected to I2C1
        self.i2c = I2C(1, scl=Pin(i2c_pin_no_clk), sda=Pin(i2c_pin_no_data), freq=400000)

    def create_framebuffer(self, width=8, height=8):
        "Allocate a bytearray of the required size and then create a MicroPython framebuffer"
        pixel_size = 2 # assume 16-bit pixels, for now
        pix_format = framebuf.RGB565
        self.fb = bytearray(width*height*pixel_size)
        self.fbuf = framebuf.FrameBuffer(self.fb, width, height, pix_format)

    # Rotation constants
    xf = [1, 24, -1, -24]
    yf = [24, -1, -24, 1]
    of = [0, 7, 7*25, 7*24]

    def update(self, x_offset=0, y_offset=0, width=8, dir=0):
        "Copy a MicroPython framebuffer bytearray to an intermediate buffer, and write it to the I2C device"
        buf = bytearray(192) # space for 8x8 LED array, 3 bytes per LED
        src = 2*(x_offset + width*y_offset) # calculate the first pixel address
        for y in range(8):
            for x in range(8):
                # Extract a 16-bit pixel (x,y) from the specified framebuffer bytearray
                pix = self.fb[src] + (self.fb[src+1] << 8)  # combine the lo and hi bytes into a 16-bit pixel
                # Apply rotation to calculate destination offset
                dst = SenseHat.of[dir] + SenseHat.xf[dir]*x + SenseHat.yf[dir]*y
                # Write the RGB components from the 16-bit pixel (as 6-bit values) to an I2C bytearray
                buf[dst]      = (pix >> 11) << 1  # red
                buf[dst + 8]  = 0x2f & (pix >> 5) # green
                buf[dst + 16] = (pix & 0x1f) << 1 # blue
                src += 2
            src += width + width - 16
        # send the bytearray to the I2C LED grid
        self.i2c.writeto_mem(0x46, 0, buf)

    def read_stick(self):
        "Read state of Sense Hat joystick, causes LEDs to flicker"
        b = self.i2c.readfrom_mem(0x46,0xf2,1) # read joystick

        return int.from_bytes(b, 'little')

string = "Hello World!"
w = 8*(len(string) + 2)

hat = SenseHat()
hat.create_framebuffer(width=w)

hat.fbuf.fill(0x2f << 11)
hat.fbuf.text(string, 8, 0, 0xffff)

while True:
    joy = hat.read_stick() # note: this causes the LEDs to flicker
    if joy:
        if joy & 0x1:
            dir = 1
        elif joy & 0x2:
            dir = 0
        elif joy & 0x4:
            dir = 3
        elif joy & 0x10:
            dir = 2
        elif joy & 0x8:
            sys.exit()
        print("joy =", joy, "dir =", dir)
        for offset in range(8*(1 + len(string))):
            hat.update(x_offset=offset, width=w, dir=dir)
            time.sleep(0.025)