import time import hid class MCP2221: VID = 0x04D8 PID = 0x00DD GP_GPIO = 0b000 GP_DEDICATED = 0b001 GP_ALT0 = 0b010 GP_ALT1 = 0b011 GP_ALT2 = 0b100 def __init__(self): self._hid = hid.device() self._hid.open(MCP2221.VID, MCP2221.PID) self._reset() def _hid_xfer(self, report, response=True): # first byte is report ID, which =0 for MCP2221 # remaing bytes = 64 byte report data # https://github.com/libusb/hidapi/blob/083223e77952e1ef57e6b77796536a3359c1b2a3/hidapi/hidapi.h#L185 self._hid.write(b'\0' + report + b'\0'*(64-len(report))) if response: # return is 64 byte response report return self._hid.read(64) #---------------------------------------------------------------- # MISC #---------------------------------------------------------------- def gp_get_mode(self, pin): return self._hid_xfer(b'\x61')[22+pin] & 0x07 def gp_set_mode(self, pin, mode): # get current settings current = self._hid_xfer(b'\x61') # empty report, this is safe since 0's = no change report = bytearray(b'\x60'+b'\x00'*63) # set the alter GP flag byte report[7] = 0xFF # each pin can be set individually # but all 4 get set at once, so we need to # transpose current settings report[8] = current[22] # GP0 report[9] = current[23] # GP1 report[10] = current[24] # GP2 report[11] = current[25] # GP3 # then change only the one report[8+pin] = mode & 0x07 # and make it so self._hid_xfer(report) def _pretty_report(self, report): print(" 0 1 2 3 4 5 6 7 8 9") index = 0 for row in range(7): print("{} : ".format(row), end='') for _ in range(10): print("{:02x} ".format(report[index]), end='') index += 1 if index > 63: break print() def _status_dump(self): self._pretty_report(self._hid_xfer(b'\x10')) def _sram_dump(self): self._pretty_report(self._hid_xfer(b'\x61')) def _reset(self): self._hid_xfer(b'\x70\xAB\xCD\xEF', response=False) start = time.monotonic() while time.monotonic() - start < 5: try: self._hid.open(MCP2221.VID, MCP2221.PID) except OSError: # try again time.sleep(0.1) continue return raise OSError("open failed") #---------------------------------------------------------------- # GPIO #---------------------------------------------------------------- def gpio_set_direction(self, pin, mode): report = bytearray(b'\x50'+b'\x00'*63) # empty set GPIO report offset = 4 * (pin + 1) report[offset] = 0x01 # set pin direction report[offset+1] = mode # to this self._hid_xfer(report) def gpio_set_pin(self, pin, value): report = bytearray(b'\x50'+b'\x00'*63) # empty set GPIO report offset = 2 + 4 * pin report[offset] = 0x01 # set pin value report[offset+1] = value # to this self._hid_xfer(report) def gpio_get_pin(self, pin): resp = self._hid_xfer(b'\x51') offset = 2 + 2 * pin if resp[offset] == 0xEE: raise RuntimeError("Pin is not set for GPIO operation.") else: return resp[offset] #---------------------------------------------------------------- # I2C # # cribbed from the C driver # http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz # define RESP_I2C_IDLE 0x00 # define RESP_I2C_START_TOUT 0x12 # define RESP_I2C_RSTART_TOUT 0x17 # define RESP_I2C_WRADDRL_TOUT 0x23 # define RESP_I2C_WRADDRL_WSEND 0x21 # define RESP_I2C_WRADDRL_NACK 0x25 # define RESP_I2C_WRDATA_TOUT 0x44 # define RESP_I2C_RDDATA_TOUT 0x52 # define RESP_I2C_STOP_TOUT 0x62 #---------------------------------------------------------------- def _i2c_status(self): return self._hid_xfer(b'\x10')[8] def _i2c_cancel(self): resp = self._hid_xfer(b'\x10\x00\x10') if resp[2] == 0x10: # bus release will need "a few hundred microseconds" time.sleep(0.001) def _i2c_write(self, cmd, address, buffer, start=0, end=None): if self._i2c_status(): self._i2c_cancel() end = end if end else len(buffer) length = end - start retries = 0 while (end - start) > 0: chunk = min(end - start, 60) # write out current chunk resp = self._hid_xfer(bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, address << 1]) + buffer[start:(start+chunk)]) # check for success if resp[1] != 0x00: retries += 1 if retries >= 5: raise RuntimeError("I2C write error, max retries reached.") time.sleep(0.001) continue # try again start += chunk retries = 0 def _i2c_read(self, cmd, address, buffer, start=0, end=None): if self._i2c_status(): self._i2c_cancel() end = end if end else len(buffer) length = end - start retries = 0 while (end - start) > 0: # tell it we want to read resp = self._hid_xfer(bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, (address << 1) | 0x01])) # and then actually read resp = self._hid_xfer(b'\x40') # check for success if resp[1] != 0x00: retries += 1 if retries >= 5: raise RuntimeError("I2C write error, max retries reached.") time.sleep(0.001) continue # move data into buffer chunk = min(end - start, 60) for i, k in enumerate(range(start, start+chunk)): buffer[k] = resp[4 + i] start += chunk def i2c_configure(self, baudrate=100000): self._hid_xfer(bytes([0x10, # set parameters 0x00, # don't care 0x00, # no effect 0x20, # next byte is clock divider 12000000 // baudrate - 3])) def i2c_writeto(self, address, buffer, *, start=0, end=None): self._i2c_write(0x90, address, buffer, start, end) def i2c_readfrom_into(self, address, buffer, *, start=0, end=None): self._i2c_read(0x91, address, buffer, start, end) def i2c_writeto_then_readfrom(self, address, out_buffer, in_buffer, *, out_start=0, out_end=None, in_start=0, in_end=None): self._i2c_write(0x94, address, out_buffer, out_start, out_end) self._i2c_read(0x93, address, in_buffer, in_start, in_end) def i2c_scan(self, *, start=0, end=0x79): found = [] for addr in range(start, end+1): # try a write self.i2c_writeto(addr, b'\x00') # store if success if self._i2c_status() == 0x00: found.append(addr) # cancel and continue self._i2c_cancel() return found #---------------------------------------------------------------- # ADC #---------------------------------------------------------------- def adc_configure(self, vref=0): report = bytearray(b'\x60'+b'\x00'*63) report[5] = 1 << 7 | (vref & 0b111) self._hid_xfer(report) def adc_read(self, pin): resp = self._hid_xfer(b'\x10') return resp[49 + 2 * pin] << 8 | resp[48 + 2 * pin] #---------------------------------------------------------------- # DAC #---------------------------------------------------------------- def dac_configure(self, vref=0): report = bytearray(b'\x60'+b'\x00'*63) report[3] = 1 << 7 | (vref & 0b111) self._hid_xfer(report) def dac_write(self, pin, value): report = bytearray(b'\x60'+b'\x00'*63) report[4] = 1 << 7 | (value & 0b11111) self._hid_xfer(report) mcp2221 = MCP2221()