mirror of
https://github.com/licsber/micropython.git
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75 lines
2.0 KiB
Python
75 lines
2.0 KiB
Python
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# MicroPython driver for SPI flash
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# MIT license; Copyright (c) 2022 Damien P. George
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from micropython import const
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_PAGE_SIZE = const(256) # maximum bytes writable in one SPI transfer
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_CMD_RDSR = const(0x05)
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_CMD_WREN = const(0x06)
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_CMD_WRITE_32 = const(0x12)
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_CMD_READ_32 = const(0x13)
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_CMD_SEC_ERASE_32 = const(0x21)
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_CMD_C4READ_32 = const(0xEC)
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class SPIFlash:
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def __init__(self, spi, cs):
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self.spi = spi
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self.cs = cs
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def _wait_wel1(self):
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# wait WEL=1
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self.cs(0)
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self.spi.write(bytearray([_CMD_RDSR]))
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buf = bytearray(1)
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while True:
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self.spi.readinto(buf)
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if buf[0] & 2:
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break
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self.cs(1)
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def _wait_wip0(self):
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# wait WIP=0
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self.cs(0)
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self.spi.write(bytearray([_CMD_RDSR]))
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buf = bytearray(1)
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while True:
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self.spi.readinto(buf)
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if not (buf[0] & 1):
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break
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self.cs(1)
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def _flash_modify(self, cmd, addr, buf):
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self.cs(0)
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self.spi.write(bytearray([_CMD_WREN]))
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self.cs(1)
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self._wait_wel1()
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self.cs(0)
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self.spi.write(bytearray([cmd, addr >> 24, addr >> 16, addr >> 8, addr]))
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if buf:
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self.spi.write(buf)
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self.cs(1)
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self._wait_wip0()
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def erase_block(self, addr):
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self._flash_modify(_CMD_SEC_ERASE_32, addr, None)
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def readinto(self, addr, buf):
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self.cs(0)
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self.spi.write(bytearray([_CMD_READ_32, addr >> 16, addr >> 8, addr]))
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self.spi.readinto(buf)
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self.cs(1)
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def write(self, addr, buf):
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offset = addr & (_PAGE_SIZE - 1)
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remain = len(buf)
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buf = memoryview(buf)
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buf_offset = 0
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while remain:
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l = min(_PAGE_SIZE - offset, remain)
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self._flash_modify(_CMD_WRITE_32, addr, buf[buf_offset : buf_offset + l])
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remain -= l
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addr += l
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buf_offset += l
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offset = 0
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