circuitpython/ports/stm32/boards/LEGO_HUB_NO6/spiflash.py

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# MicroPython driver for SPI flash
# MIT license; Copyright (c) 2022 Damien P. George
from micropython import const
_PAGE_SIZE = const(256) # maximum bytes writable in one SPI transfer
_CMD_WRITE = const(0x02)
_CMD_READ = const(0x03)
_CMD_RDSR = const(0x05)
_CMD_WREN = const(0x06)
_CMD_WRITE_32 = const(0x12)
_CMD_READ_32 = const(0x13)
_CMD_SEC_ERASE = const(0x20)
_CMD_SEC_ERASE_32 = const(0x21)
_CMD_JEDEC_ID = const(0x9F)
class SPIFlash:
def __init__(self, spi, cs):
self.spi = spi
self.cs = cs
self.id = self._get_id()
# flash chip on Hub No. 6 uses 32-bit addressing
_32_bit = self.id == b"\xef\x40\x19"
self._READ = _CMD_READ_32 if _32_bit else _CMD_READ
self._WRITE = _CMD_WRITE_32 if _32_bit else _CMD_WRITE
self._ERASE = _CMD_SEC_ERASE_32 if _32_bit else _CMD_SEC_ERASE
def _get_id(self):
self.cs(0)
self.spi.write(bytearray([_CMD_JEDEC_ID]))
buf = self.spi.read(3)
self.cs(1)
return buf
def _wait_wel1(self):
# wait WEL=1
self.cs(0)
self.spi.write(bytearray([_CMD_RDSR]))
buf = bytearray(1)
while True:
self.spi.readinto(buf)
if buf[0] & 2:
break
self.cs(1)
def _wait_wip0(self):
# wait WIP=0
self.cs(0)
self.spi.write(bytearray([_CMD_RDSR]))
buf = bytearray(1)
while True:
self.spi.readinto(buf)
if not (buf[0] & 1):
break
self.cs(1)
def _flash_modify(self, cmd, addr, buf):
self.cs(0)
self.spi.write(bytearray([_CMD_WREN]))
self.cs(1)
self._wait_wel1()
self.cs(0)
self.spi.write(bytearray([cmd, addr >> 24, addr >> 16, addr >> 8, addr]))
if buf:
self.spi.write(buf)
self.cs(1)
self._wait_wip0()
def erase_block(self, addr):
self._flash_modify(self._ERASE, addr, None)
def readinto(self, addr, buf):
self.cs(0)
self.spi.write(bytearray([self._READ, addr >> 16, addr >> 8, addr]))
self.spi.readinto(buf)
self.cs(1)
def write(self, addr, buf):
offset = addr & (_PAGE_SIZE - 1)
remain = len(buf)
buf = memoryview(buf)
buf_offset = 0
while remain:
l = min(_PAGE_SIZE - offset, remain)
self._flash_modify(self._WRITE, addr, buf[buf_offset : buf_offset + l])
remain -= l
addr += l
buf_offset += l
offset = 0