mirror of
https://github.com/licsber/micropython.git
synced 2024-09-20 09:00:23 +08:00
861fbf6ab5
These files all use decorators (@asm_thumb, @asm_pio) that add names to the function scope, that the linter cannot see. It's useful to clear them in the file not in pyproject.toml as example code will be copied and adapted elsewhere, and those developers may also use Ruff (we hope!) Signed-off-by: Angus Gratton <angus@redyak.com.au>
48 lines
1.3 KiB
Python
48 lines
1.3 KiB
Python
# Example using PIO to create a UART TX interface
|
|
|
|
# ruff: noqa: F821 - @asm_pio decorator adds names to function scope
|
|
|
|
from machine import Pin
|
|
from rp2 import PIO, StateMachine, asm_pio
|
|
|
|
UART_BAUD = 115200
|
|
PIN_BASE = 10
|
|
NUM_UARTS = 8
|
|
|
|
|
|
@asm_pio(sideset_init=PIO.OUT_HIGH, out_init=PIO.OUT_HIGH, out_shiftdir=PIO.SHIFT_RIGHT)
|
|
def uart_tx():
|
|
# fmt: off
|
|
# Block with TX deasserted until data available
|
|
pull()
|
|
# Initialise bit counter, assert start bit for 8 cycles
|
|
set(x, 7) .side(0) [7]
|
|
# Shift out 8 data bits, 8 execution cycles per bit
|
|
label("bitloop")
|
|
out(pins, 1) [6]
|
|
jmp(x_dec, "bitloop")
|
|
# Assert stop bit for 8 cycles total (incl 1 for pull())
|
|
nop() .side(1) [6]
|
|
# fmt: on
|
|
|
|
|
|
# Now we add 8 UART TXs, on pins 10 to 17. Use the same baud rate for all of them.
|
|
uarts = []
|
|
for i in range(NUM_UARTS):
|
|
sm = StateMachine(
|
|
i, uart_tx, freq=8 * UART_BAUD, sideset_base=Pin(PIN_BASE + i), out_base=Pin(PIN_BASE + i)
|
|
)
|
|
sm.active(1)
|
|
uarts.append(sm)
|
|
|
|
|
|
# We can print characters from each UART by pushing them to the TX FIFO
|
|
def pio_uart_print(sm, s):
|
|
for c in s:
|
|
sm.put(ord(c))
|
|
|
|
|
|
# Print a different message from each UART
|
|
for i, u in enumerate(uarts):
|
|
pio_uart_print(u, "Hello from UART {}!\n".format(i))
|