50 wiersze
1.8 KiB
Python
50 wiersze
1.8 KiB
Python
import rp2
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from machine import Pin
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@rp2.asm_pio(out_shiftdir=0, autopull=True, pull_thresh=8, autopush=True, push_thresh=8, sideset_init=(rp2.PIO.OUT_LOW, rp2.PIO.OUT_HIGH), out_init=rp2.PIO.OUT_LOW)
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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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# Would normally do this via exec() but in this case it's in the instruction memory and is only run once
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set(x, 6)
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# Actual program body follows
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wrap_target()
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pull(ifempty) .side(0x2) [1]
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label("bitloop")
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out(pins, 1) .side(0x0) [1]
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in_(pins, 1) .side(0x1)
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jmp(x_dec, "bitloop") .side(0x1)
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out(pins, 1) .side(0x0)
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set(x, 6) .side(0x0) # Note this could be replaced with mov x, y for programmable frame size
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in_(pins, 1) .side(0x1)
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jmp(not_osre, "bitloop") .side(0x1) # Fallthru if TXF empties
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nop() .side(0x0) [1] # CSn back porch
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wrap()
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class PIOSPI:
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def __init__(self, sm_id, pin_mosi, pin_miso, pin_sck, cpha=False, cpol=False, freq=1000000):
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assert(not(cpol or cpha))
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self._sm = rp2.StateMachine(sm_id, spi_cpha0, freq=4*freq, sideset_base=Pin(pin_sck), out_base=Pin(pin_mosi), in_base=Pin(pin_sck))
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self._sm.active(1)
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# Note this code will die spectacularly cause we're not draining the RX FIFO
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def write_blocking(wdata):
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for b in wdata:
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self._sm.put(b << 24)
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def read_blocking(n):
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data = []
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for i in range(n):
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data.append(self._sm.get() & 0xff)
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return data
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def write_read_blocking(wdata):
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rdata = []
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for b in wdata:
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self._sm.put(b << 24)
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rdata.append(self._sm.get() & 0xff)
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return rdata
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