kopia lustrzana https://github.com/peterhinch/micropython-samples
Update spi_dma.py
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commit
d69cc9fcaa
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temp/spi_dma.py
118
temp/spi_dma.py
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# Derived from https://github.com/raspberrypi/pico-micropython-examples/blob/master/pio/pio_spi.py
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# Derived from https://github.com/raspberrypi/pico-micropython-examples/blob/master/pio/pio_spi.py
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import rp2
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import rp2
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from machine import Pin
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from machine import Pin
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import time
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import asyncio
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from micropython import alloc_emergency_exception_buf
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# ***** Define connfiguration *****
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alloc_emergency_exception_buf(100)
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sm_num = 0
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pio_num = 0
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freq = 1_000_000
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pincs = Pin(20, Pin.OUT)
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pin_sck = Pin(18)
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pin_mosi = Pin(19)
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# ***** Transfer complete callback *****
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def callback(dma):
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pincs(1)
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# Flag user code that transfer is complete
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# *****
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@rp2.asm_pio(autopull=True, pull_thresh=8, sideset_init=rp2.PIO.OUT_LOW, out_init=rp2.PIO.OUT_LOW)
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@rp2.asm_pio(autopull=True, pull_thresh=8, sideset_init=(rp2.PIO.OUT_LOW,), out_init=rp2.PIO.OUT_LOW)
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def spi_cpha0():
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def spi_cpha0():
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# Note X must be preinitialised by setup code before first byte, we reload after sending each byte
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# Note X must be preinitialised by setup code before first byte, we reload after sending each byte
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set(x, 6)
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set(x, 6)
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# Actual program body follows
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# Actual program body follows
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wrap_target()
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wrap_target()
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pull(ifempty) .side(0x0) [1]
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pull(ifempty).side(0x0)[1]
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label("bitloop")
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label("bitloop")
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out(pins, 1) .side(0x0) [1]
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out(pins, 1).side(0x0)[1]
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#mov(y, y) .side(0x1)
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jmp(x_dec, "bitloop").side(0x1)[1]
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jmp(x_dec, "bitloop") .side(0x1) [1]
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out(pins, 1) .side(0x0)
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out(pins, 1).side(0x0)
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set(x, 6) .side(0x0)
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set(x, 6).side(0x0)
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mov(y, y) .side(0x1) # NOP
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mov(y, y).side(0x1) # NOP
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jmp(not_osre, "bitloop") .side(0x1) # Fallthru if TXFIFO empties
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jmp(not_osre, "bitloop").side(0x1) # Fallthru if TXFIFO empties
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wrap()
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wrap()
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piospi_sm = rp2.StateMachine(sm_num, spi_cpha0, freq=4*freq, sideset_base=pin_sck, out_base=pin_mosi)
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piospi_sm.active(1)
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DATA_REQUEST_INDEX = (pio_num << 3) + sm_num
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# Get data request channel for a SM: RP2040 datasheet 2.5.3 RP2350 12.6.4.1
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def dreq(sm, rx=False):
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d = (sm & 3) + ((sm >> 2) << 3)
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return 4 + d if rx else d
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class RP2_SPI_DMA_MASTER:
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def __init__(self, sm_num, freq, sck, mosi, callback):
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self._sm_num = sm_num
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self._dma = rp2.DMA()
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self._dma.irq(handler=callback, hard=True) # Assign callback
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dc = dreq(sm_num) # Data request channel
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# Transfer bytes, don't increment the write address, irq at end, and pace the transfer.
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self._ctrl = self._dma.pack_ctrl(size=0, inc_write=False, irq_quiet=False, treq_sel=dc)
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f = 4 * freq # 4 clock cycles per bit
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self._sm = rp2.StateMachine(sm_num, spi_cpha0, freq=f, sideset_base=sck, out_base=mosi)
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self._sm.active(1)
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def close(self):
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self._dma.active(0)
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self._sm.active(0)
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def write(self, data):
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self._dma.config(read=data, write=self._sm, count=len(data), ctrl=self._ctrl, trigger=True)
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d = rp2.DMA()
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d.irq(handler=callback, hard=True) # Assign callback
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# Transfer bytes, rather than words, don't increment the write address, irq at end, and pace the transfer.
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c = d.pack_ctrl(size=0, inc_write=False, irq_quiet=False, treq_sel=DATA_REQUEST_INDEX)
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def send(data):
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pincs(0) # Assert CS/
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d.config(
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read=data,
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write=piospi_sm,
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count=len(data),
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ctrl=c,
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trigger=True
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)
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# ***** Test Script *****
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# ***** Test Script *****
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n = 0
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pin_cs = Pin(20, Pin.OUT, value=1)
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while True:
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pin_sck = Pin(18, Pin.OUT, value=0)
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src_data = b'the quick brown fox jumps over the lazy dog'
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pin_mosi = Pin(19, Pin.OUT, value=0)
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send(src_data) # "Immediate" return.
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time.sleep(1)
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tsf = asyncio.ThreadSafeFlag()
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print(n)
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n += 1
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def callback(dma): # Hard ISR
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tsf.set() # Flag user code that transfer is complete
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spi = RP2_SPI_DMA_MASTER(0, 1_000_000, pin_sck, pin_mosi, callback)
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async def eot(): # Handle end of transfer
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while True:
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await tsf.wait()
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pin_cs(1)
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async def main():
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src_data = b"the quick brown fox jumps over the lazy dog"
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asyncio.create_task(eot())
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n = 0
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while True:
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pin_cs(0)
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spi.write(src_data) # "Immediate" return.
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await asyncio.sleep(1)
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print(n)
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n += 1
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try:
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asyncio.run(main())
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except KeyboardInterrupt:
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spi.close()
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asyncio.new_event_loop()
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