58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
import time
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from micropython import const
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from adafruit_bus_device.spi_device import SPIDevice
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import busio
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from board import *
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SRAM_READ = const(0x03)
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SRAM_WRITE = const(0x02)
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SRAM_RDSR = const(0x05)
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SRAM_WRSR = const(0x01)
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SRAM_SEQUENTIAL_MODE = const(1 << 6)
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class Adafruit_MCP_SRAM:
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def __init__(self, cs, spi):
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# Handle hardware SPI
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self.spi_device = spi
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with self.spi_device as spi:
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spi.write(bytearray([0xFF, 0xFF, 0xFF]))
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def write(self, addr, buf, reg=SRAM_WRITE):
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c = bytearray([reg, (addr >> 16) & 0xFF, (addr >> 8) & 0xFF, addr & 0xFF] + bytearray(buf))
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with self.spi_device as spi:
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spi.write(c)
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def read(self, addr, length, reg=SRAM_READ):
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c = bytearray([reg, (addr >> 16) & 0xFF, (addr >> 8) & 0xFF, addr & 0xFF] + bytearray(buf))
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buf = bytearray(length)
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with self.spi_device as spi:
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spi.readinto(buf)
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return buf
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def read8(self, addr, reg=SRAM_READ):
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return ord(self.read(addr, 1, reg)[0])
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def read16(self, addr, reg=SRAM_READ):
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buf = self.read(addr, 2, reg)
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return (buf[0] << 8 | buf[1])
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def write8(self, addr, value, reg=SRAM_WRITE):
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self.write(addr, [value], reg)
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def write16(self, addr, value, reg=SRAM_WRITE):
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self.write(addr, [value >> 8, value], reg)
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def erase(self, addr, length, value):
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pos = 0
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while pos < length:
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buf = [value] * min(64, length - pos)
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self.write(addr, buf)
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addr = addr + len(buf)
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pos = pos + len(buf)
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