"""Chip Definition for MCP2221""" import os import time import hid # Here if you need it MCP2221_HID_DELAY = float(os.environ.get("BLINKA_MCP2221_HID_DELAY", 0)) # Use to set delay between reset and device reopen. if negative, don't reset at all MCP2221_RESET_DELAY = float(os.environ.get("BLINKA_MCP2221_RESET_DELAY", 0.5)) # from the C driver # http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz # others (???) determined during driver developement RESP_ERR_NOERR = 0x00 RESP_ADDR_NACK = 0x25 RESP_READ_ERR = 0x7F RESP_READ_COMPL = 0x55 RESP_READ_PARTIAL = 0x54 # ??? RESP_I2C_IDLE = 0x00 RESP_I2C_START_TOUT = 0x12 RESP_I2C_RSTART_TOUT = 0x17 RESP_I2C_WRADDRL_TOUT = 0x23 RESP_I2C_WRADDRL_WSEND = 0x21 RESP_I2C_WRADDRL_NACK = 0x25 RESP_I2C_WRDATA_TOUT = 0x44 RESP_I2C_RDDATA_TOUT = 0x52 RESP_I2C_STOP_TOUT = 0x62 RESP_I2C_MOREDATA = 0x43 # ??? RESP_I2C_PARTIALDATA = 0x41 # ??? RESP_I2C_WRITINGNOSTOP = 0x45 # ??? MCP2221_RETRY_MAX = 50 MCP2221_MAX_I2C_DATA_LEN = 60 MASK_ADDR_NACK = 0x40 class MCP2221: """MCP2221 Device Class Definition""" 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) if MCP2221_RESET_DELAY >= 0: self._reset() self._gp_config = [0x07] * 4 # "don't care" initial value for pin in range(4): self.gp_set_mode(pin, self.GP_GPIO) # set to GPIO mode self.gpio_set_direction(pin, 1) # set to INPUT def _hid_xfer(self, report, response=True): """Perform HID Transfer""" # 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))) time.sleep(MCP2221_HID_DELAY) if response: # return is 64 byte response report return self._hid.read(64) return None # ---------------------------------------------------------------- # MISC # ---------------------------------------------------------------- def gp_get_mode(self, pin): """Get Current Pin Mode""" return self._hid_xfer(b"\x61")[22 + pin] & 0x07 def gp_set_mode(self, pin, mode): """Set Current Pin Mode""" # already set to that mode? mode &= 0x07 if mode == (self._gp_config[pin] & 0x07): return # update GP mode for pin self._gp_config[pin] = mode # 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 # add GP setttings report[8] = self._gp_config[0] report[9] = self._gp_config[1] report[10] = self._gp_config[2] report[11] = self._gp_config[3] # and make it so self._hid_xfer(report) def _pretty_report(self, register): report = self._hid_xfer(register) 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(b"\x10") def _sram_dump(self): self._pretty_report(b"\x61") def _reset(self): self._hid_xfer(b"\x70\xAB\xCD\xEF", response=False) time.sleep(MCP2221_RESET_DELAY) 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): """Set Current GPIO Pin Direction""" if mode: # set bit 3 for INPUT self._gp_config[pin] |= 1 << 3 else: # clear bit 3 for OUTPUT self._gp_config[pin] &= ~(1 << 3) 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): """Set Current GPIO Pin Value""" if value: # set bit 4 self._gp_config[pin] |= 1 << 4 else: # clear bit 4 self._gp_config[pin] &= ~(1 << 4) 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): """Get Current GPIO Pin Value""" resp = self._hid_xfer(b"\x51") offset = 2 + 2 * pin if resp[offset] == 0xEE: raise RuntimeError("Pin is not set for GPIO operation.") return resp[offset] # ---------------------------------------------------------------- # I2C # ---------------------------------------------------------------- def _i2c_status(self): resp = self._hid_xfer(b"\x10") if resp[1] != 0: raise RuntimeError("Couldn't get I2C status") return resp def _i2c_state(self): return self._i2c_status()[8] def _i2c_cancel(self): resp = self._hid_xfer(b"\x10\x00\x10") if resp[1] != 0x00: raise RuntimeError("Couldn't cancel I2C") if resp[2] == 0x10: # bus release will need "a few hundred microseconds" time.sleep(0.001) # pylint: disable=too-many-arguments def _i2c_write(self, cmd, address, buffer, start=0, end=None): if self._i2c_state() != 0x00: self._i2c_cancel() end = end if end else len(buffer) length = end - start retries = 0 while (end - start) > 0: chunk = min(end - start, MCP2221_MAX_I2C_DATA_LEN) # 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: if resp[2] in ( RESP_I2C_START_TOUT, RESP_I2C_WRADDRL_TOUT, RESP_I2C_WRADDRL_NACK, RESP_I2C_WRDATA_TOUT, RESP_I2C_STOP_TOUT, ): raise RuntimeError("Unrecoverable I2C state failure") retries += 1 if retries >= MCP2221_RETRY_MAX: raise RuntimeError("I2C write error, max retries reached.") time.sleep(0.001) continue # try again # yay chunk sent! while self._i2c_state() == RESP_I2C_PARTIALDATA: time.sleep(0.001) start += chunk retries = 0 # check status in another loop for _ in range(MCP2221_RETRY_MAX): status = self._i2c_status() if status[20] & MASK_ADDR_NACK: raise RuntimeError("I2C slave address was NACK'd") usb_cmd_status = status[8] if usb_cmd_status == 0: break if usb_cmd_status == RESP_I2C_WRITINGNOSTOP and cmd == 0x94: break # this is OK too! if usb_cmd_status in ( RESP_I2C_START_TOUT, RESP_I2C_WRADDRL_TOUT, RESP_I2C_WRADDRL_NACK, RESP_I2C_WRDATA_TOUT, RESP_I2C_STOP_TOUT, ): raise RuntimeError("Unrecoverable I2C state failure") time.sleep(0.001) else: raise RuntimeError("I2C write error: max retries reached.") # whew success! def _i2c_read(self, cmd, address, buffer, start=0, end=None): if self._i2c_state() not in (RESP_I2C_WRITINGNOSTOP, 0): self._i2c_cancel() end = end if end else len(buffer) length = end - start # tell it we want to read resp = self._hid_xfer( bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, (address << 1) | 0x01]) ) # check for success if resp[1] != 0x00: raise RuntimeError("Unrecoverable I2C read failure") # and now the read part while (end - start) > 0: for _ in range(MCP2221_RETRY_MAX): # the actual read resp = self._hid_xfer(b"\x40") # check for success if resp[1] == RESP_I2C_PARTIALDATA: time.sleep(0.001) continue if resp[1] != 0x00: raise RuntimeError("Unrecoverable I2C read failure") if resp[2] == RESP_ADDR_NACK: raise RuntimeError("I2C NACK") if resp[3] == 0x00 and resp[2] == 0x00: break if resp[3] == RESP_READ_ERR: time.sleep(0.001) continue if resp[2] in (RESP_READ_COMPL, RESP_READ_PARTIAL): break else: raise RuntimeError("I2C read error: max retries reached.") # 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 # pylint: enable=too-many-arguments def _i2c_configure(self, baudrate=100000): """Configure I2C""" 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): """Write data from the buffer to an address""" self._i2c_write(0x90, address, buffer, start, end) def i2c_readfrom_into(self, address, buffer, *, start=0, end=None): """Read data from an address and into the buffer""" 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, ): """Write data from buffer_out to an address and then read data from an address and into buffer_in """ 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): """Perform an I2C Device Scan""" found = [] for addr in range(start, end + 1): # try a write try: self.i2c_writeto(addr, b"\x00") except RuntimeError: # no reply! continue # store if success found.append(addr) return found # ---------------------------------------------------------------- # ADC # ---------------------------------------------------------------- def adc_configure(self, vref=0): """Configure the Analog-to-Digital Converter""" report = bytearray(b"\x60" + b"\x00" * 63) report[5] = 1 << 7 | (vref & 0b111) self._hid_xfer(report) def adc_read(self, pin): """Read from the Analog-to-Digital Converter""" resp = self._hid_xfer(b"\x10") return resp[49 + 2 * pin] << 8 | resp[48 + 2 * pin] # ---------------------------------------------------------------- # DAC # ---------------------------------------------------------------- def dac_configure(self, vref=0): """Configure the Digital-to-Analog Converter""" report = bytearray(b"\x60" + b"\x00" * 63) report[3] = 1 << 7 | (vref & 0b111) self._hid_xfer(report) # pylint: disable=unused-argument def dac_write(self, pin, value): """Write to the Digital-to-Analog Converter""" report = bytearray(b"\x60" + b"\x00" * 63) report[4] = 1 << 7 | (value & 0b11111) self._hid_xfer(report) # pylint: enable=unused-argument mcp2221 = MCP2221()