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102 lines
3.1 KiB
102 lines
3.1 KiB
import gex
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class I2C(gex.Unit):
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"""
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I2C master direct access
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"""
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def _type(self):
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return 'I2C'
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def _begin_i2c_pld(self, address:int, a10bit:bool=False):
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pb = gex.PayloadBuilder()
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if a10bit: address |= 0x8000 # indication for the Unit driver that it's a 10b address
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pb.u16(address)
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return pb
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def write(self, address:int, payload, a10bit:bool=False, confirm=True):
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"""
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Write to an address
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"""
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pb = self._begin_i2c_pld(address, a10bit)
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pb.blob(payload) # payload to write
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self._send(0x00, pb.close(), confirm=confirm)
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def read(self, address:int, count, a10bit:bool=False):
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"""
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Read from an address
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"""
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pb = self._begin_i2c_pld(address, a10bit)
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pb.u16(count) # number of bytes to read
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self._query(0x01, pb.close())
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def read_reg(self, address:int, reg, width:int=1, a10bit:bool=False, endian='little'):
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"""
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Read a single register
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"""
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return self.read_regs(address, reg, count=1, width=width, a10bit=a10bit, endian=endian)[0]
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def read_regs(self, address:int, reg, count:int, width:int=1, a10bit:bool=False, endian='little'):
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"""
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Read multiple registers from an address
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"""
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pb = self._begin_i2c_pld(address, a10bit)
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pb.u8(reg)
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pb.u16(width*count) # we assume the device will auto-increment (most do)
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resp = self._query(0x03, pb.close())
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fields = []
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pp = gex.PayloadParser(resp.data, endian=endian)
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if width==1:
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for i in range(0, count):
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fields.append(pp.u8())
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elif width==2:
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for i in range(0, count):
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fields.append(pp.u16())
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elif width==3:
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for i in range(0, count):
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fields.append(pp.u24())
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elif width==4:
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for i in range(0, count):
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fields.append(pp.u32())
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else:
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raise Exception("Bad width")
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return fields
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def write_reg(self, address:int, reg, value, width:int=1, a10bit:bool=False, endian='little', confirm=True):
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"""
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Write a to a single register.
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value can be int or array (in which case `width` applies to each item)
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"""
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pb = self._begin_i2c_pld(address, a10bit)
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pb.u8(reg)
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pb.endian = endian
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arr = value
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if type(arr) is int:
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arr = [value]
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if width == 1:
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pb.blob(arr)
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elif width == 2:
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for v in arr:
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pb.u16(v)
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elif width == 3:
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for v in arr:
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pb.u24(v)
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elif width == 4:
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for v in arr:
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pb.u32(v)
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else:
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raise Exception("Bad width")
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self._send(0x02, pb.close(), confirm=confirm)
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def write_byte_data(self, address, reg, value):
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""" Compatibility alias for python3-smbus """
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return self.write_reg(address, reg, value)
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def write_i2c_block_data(self, address, reg, block):
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""" Compatibility alias for python3-smbus """
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return self.write_reg(address, reg, block)
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