403 lines
13 KiB
Python
403 lines
13 KiB
Python
# SPDX-FileCopyrightText: 2021 Melissa LeBlanc-Williams for Adafruit Industries
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#
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# SPDX-License-Identifier: MIT
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"""Chip Definition for MCP2221"""
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import os
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import time
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import atexit
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import hid
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# Here if you need it
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MCP2221_HID_DELAY = float(os.environ.get("BLINKA_MCP2221_HID_DELAY", 0))
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# Use to set delay between reset and device reopen. if negative, don't reset at all
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MCP2221_RESET_DELAY = float(os.environ.get("BLINKA_MCP2221_RESET_DELAY", 0.5))
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# from the C driver
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# http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz
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# others (???) determined during driver developement
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RESP_ERR_NOERR = 0x00
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RESP_ADDR_NACK = 0x25
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RESP_READ_ERR = 0x7F
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RESP_READ_COMPL = 0x55
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RESP_READ_PARTIAL = 0x54 # ???
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RESP_I2C_IDLE = 0x00
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RESP_I2C_START_TOUT = 0x12
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RESP_I2C_RSTART_TOUT = 0x17
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RESP_I2C_WRADDRL_TOUT = 0x23
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RESP_I2C_WRADDRL_WSEND = 0x21
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RESP_I2C_WRADDRL_NACK = 0x25
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RESP_I2C_WRDATA_TOUT = 0x44
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RESP_I2C_RDDATA_TOUT = 0x52
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RESP_I2C_STOP_TOUT = 0x62
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RESP_I2C_MOREDATA = 0x43 # ???
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RESP_I2C_PARTIALDATA = 0x41 # ???
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RESP_I2C_WRITINGNOSTOP = 0x45 # ???
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MCP2221_RETRY_MAX = 50
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MCP2221_MAX_I2C_DATA_LEN = 60
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MASK_ADDR_NACK = 0x40
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class MCP2221:
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"""MCP2221 Device Class Definition"""
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VID = 0x04D8
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PID = 0x00DD
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GP_GPIO = 0b000
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GP_DEDICATED = 0b001
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GP_ALT0 = 0b010
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GP_ALT1 = 0b011
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GP_ALT2 = 0b100
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def __init__(self):
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self._hid = hid.device()
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self._hid.open(MCP2221.VID, MCP2221.PID)
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# make sure the device gets closed before exit
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atexit.register(self.close)
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if MCP2221_RESET_DELAY >= 0:
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self._reset()
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self._gp_config = [0x07] * 4 # "don't care" initial value
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for pin in range(4):
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self.gp_set_mode(pin, self.GP_GPIO) # set to GPIO mode
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self.gpio_set_direction(pin, 1) # set to INPUT
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def close(self):
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"""Close the hid device. Does nothing if the device is not open."""
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self._hid.close()
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def __del__(self):
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# try to close the device before destroying the instance
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self.close()
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def _hid_xfer(self, report, response=True):
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"""Perform HID Transfer"""
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# first byte is report ID, which =0 for MCP2221
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# remaing bytes = 64 byte report data
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# https://github.com/libusb/hidapi/blob/083223e77952e1ef57e6b77796536a3359c1b2a3/hidapi/hidapi.h#L185
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self._hid.write(b"\0" + report + b"\0" * (64 - len(report)))
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time.sleep(MCP2221_HID_DELAY)
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if response:
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# return is 64 byte response report
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return self._hid.read(64)
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return None
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# ----------------------------------------------------------------
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# MISC
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# ----------------------------------------------------------------
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def gp_get_mode(self, pin):
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"""Get Current Pin Mode"""
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return self._hid_xfer(b"\x61")[22 + pin] & 0x07
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def gp_set_mode(self, pin, mode):
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"""Set Current Pin Mode"""
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# already set to that mode?
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mode &= 0x07
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if mode == (self._gp_config[pin] & 0x07):
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return
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# update GP mode for pin
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self._gp_config[pin] = mode
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# empty report, this is safe since 0's = no change
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report = bytearray(b"\x60" + b"\x00" * 63)
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# set the alter GP flag byte
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report[7] = 0xFF
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# add GP setttings
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report[8] = self._gp_config[0]
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report[9] = self._gp_config[1]
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report[10] = self._gp_config[2]
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report[11] = self._gp_config[3]
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# and make it so
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self._hid_xfer(report)
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def _pretty_report(self, register):
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report = self._hid_xfer(register)
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print(" 0 1 2 3 4 5 6 7 8 9")
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index = 0
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for row in range(7):
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print("{} : ".format(row), end="")
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for _ in range(10):
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print("{:02x} ".format(report[index]), end="")
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index += 1
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if index > 63:
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break
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print()
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def _status_dump(self):
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self._pretty_report(b"\x10")
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def _sram_dump(self):
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self._pretty_report(b"\x61")
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def _reset(self):
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self._hid_xfer(b"\x70\xAB\xCD\xEF", response=False)
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self._hid.close()
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time.sleep(MCP2221_RESET_DELAY)
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start = time.monotonic()
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while time.monotonic() - start < 5:
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try:
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self._hid.open(MCP2221.VID, MCP2221.PID)
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except OSError:
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# try again
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time.sleep(0.1)
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continue
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return
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raise OSError("open failed")
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# ----------------------------------------------------------------
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# GPIO
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# ----------------------------------------------------------------
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def gpio_set_direction(self, pin, mode):
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"""Set Current GPIO Pin Direction"""
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if mode:
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# set bit 3 for INPUT
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self._gp_config[pin] |= 1 << 3
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else:
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# clear bit 3 for OUTPUT
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self._gp_config[pin] &= ~(1 << 3)
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report = bytearray(b"\x50" + b"\x00" * 63) # empty set GPIO report
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offset = 4 * (pin + 1)
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report[offset] = 0x01 # set pin direction
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report[offset + 1] = mode # to this
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self._hid_xfer(report)
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def gpio_set_pin(self, pin, value):
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"""Set Current GPIO Pin Value"""
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if value:
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# set bit 4
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self._gp_config[pin] |= 1 << 4
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else:
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# clear bit 4
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self._gp_config[pin] &= ~(1 << 4)
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report = bytearray(b"\x50" + b"\x00" * 63) # empty set GPIO report
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offset = 2 + 4 * pin
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report[offset] = 0x01 # set pin value
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report[offset + 1] = value # to this
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self._hid_xfer(report)
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def gpio_get_pin(self, pin):
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"""Get Current GPIO Pin Value"""
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resp = self._hid_xfer(b"\x51")
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offset = 2 + 2 * pin
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if resp[offset] == 0xEE:
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raise RuntimeError("Pin is not set for GPIO operation.")
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return resp[offset]
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# ----------------------------------------------------------------
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# I2C
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# ----------------------------------------------------------------
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def _i2c_status(self):
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resp = self._hid_xfer(b"\x10")
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if resp[1] != 0:
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raise RuntimeError("Couldn't get I2C status")
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return resp
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def _i2c_state(self):
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return self._i2c_status()[8]
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def _i2c_cancel(self):
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resp = self._hid_xfer(b"\x10\x00\x10")
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if resp[1] != 0x00:
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raise RuntimeError("Couldn't cancel I2C")
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if resp[2] == 0x10:
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# bus release will need "a few hundred microseconds"
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time.sleep(0.001)
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# pylint: disable=too-many-arguments,too-many-branches
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def _i2c_write(self, cmd, address, buffer, start=0, end=None):
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if self._i2c_state() != 0x00:
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self._i2c_cancel()
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end = end if end else len(buffer)
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length = end - start
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retries = 0
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while (end - start) > 0 or not buffer:
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chunk = min(end - start, MCP2221_MAX_I2C_DATA_LEN)
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# write out current chunk
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resp = self._hid_xfer(
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bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, address << 1])
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+ buffer[start : (start + chunk)]
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)
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# check for success
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if resp[1] != 0x00:
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if resp[2] in (
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RESP_I2C_START_TOUT,
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RESP_I2C_WRADDRL_TOUT,
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RESP_I2C_WRADDRL_NACK,
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RESP_I2C_WRDATA_TOUT,
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RESP_I2C_STOP_TOUT,
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):
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raise RuntimeError("Unrecoverable I2C state failure")
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retries += 1
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if retries >= MCP2221_RETRY_MAX:
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raise RuntimeError("I2C write error, max retries reached.")
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time.sleep(0.001)
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continue # try again
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# yay chunk sent!
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while self._i2c_state() == RESP_I2C_PARTIALDATA:
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time.sleep(0.001)
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if not buffer:
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break
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start += chunk
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retries = 0
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# check status in another loop
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for _ in range(MCP2221_RETRY_MAX):
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status = self._i2c_status()
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if status[20] & MASK_ADDR_NACK:
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raise OSError("I2C slave address was NACK'd")
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usb_cmd_status = status[8]
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if usb_cmd_status == 0:
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break
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if usb_cmd_status == RESP_I2C_WRITINGNOSTOP and cmd == 0x94:
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break # this is OK too!
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if usb_cmd_status in (
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RESP_I2C_START_TOUT,
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RESP_I2C_WRADDRL_TOUT,
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RESP_I2C_WRADDRL_NACK,
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RESP_I2C_WRDATA_TOUT,
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RESP_I2C_STOP_TOUT,
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):
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raise RuntimeError("Unrecoverable I2C state failure")
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time.sleep(0.001)
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else:
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raise RuntimeError("I2C write error: max retries reached.")
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# whew success!
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def _i2c_read(self, cmd, address, buffer, start=0, end=None):
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if self._i2c_state() not in (RESP_I2C_WRITINGNOSTOP, 0):
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self._i2c_cancel()
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end = end if end else len(buffer)
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length = end - start
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# tell it we want to read
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resp = self._hid_xfer(
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bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, (address << 1) | 0x01])
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)
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# check for success
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if resp[1] != 0x00:
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raise RuntimeError("Unrecoverable I2C read failure")
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# and now the read part
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while (end - start) > 0:
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for _ in range(MCP2221_RETRY_MAX):
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# the actual read
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resp = self._hid_xfer(b"\x40")
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# check for success
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if resp[1] == RESP_I2C_PARTIALDATA:
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time.sleep(0.001)
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continue
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if resp[1] != 0x00:
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raise RuntimeError("Unrecoverable I2C read failure")
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if resp[2] == RESP_ADDR_NACK:
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raise RuntimeError("I2C NACK")
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if resp[3] == 0x00 and resp[2] == 0x00:
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break
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if resp[3] == RESP_READ_ERR:
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time.sleep(0.001)
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continue
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if resp[2] in (RESP_READ_COMPL, RESP_READ_PARTIAL):
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break
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else:
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raise RuntimeError("I2C read error: max retries reached.")
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# move data into buffer
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chunk = min(end - start, 60)
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for i, k in enumerate(range(start, start + chunk)):
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buffer[k] = resp[4 + i]
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start += chunk
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# pylint: enable=too-many-arguments
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def _i2c_configure(self, baudrate=100000):
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"""Configure I2C"""
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self._hid_xfer(
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bytes(
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[
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0x10, # set parameters
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0x00, # don't care
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0x00, # no effect
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0x20, # next byte is clock divider
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12000000 // baudrate - 3,
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]
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)
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)
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def i2c_writeto(self, address, buffer, *, start=0, end=None):
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"""Write data from the buffer to an address"""
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self._i2c_write(0x90, address, buffer, start, end)
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def i2c_readfrom_into(self, address, buffer, *, start=0, end=None):
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"""Read data from an address and into the buffer"""
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self._i2c_read(0x91, address, buffer, start, end)
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def i2c_writeto_then_readfrom(
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self,
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address,
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out_buffer,
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in_buffer,
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*,
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out_start=0,
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out_end=None,
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in_start=0,
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in_end=None,
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):
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"""Write data from buffer_out to an address and then
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read data from an address and into buffer_in
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"""
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self._i2c_write(0x94, address, out_buffer, out_start, out_end)
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self._i2c_read(0x93, address, in_buffer, in_start, in_end)
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def i2c_scan(self, *, start=0, end=0x79):
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"""Perform an I2C Device Scan"""
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found = []
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for addr in range(start, end + 1):
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# try a write
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try:
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self.i2c_writeto(addr, b"\x00")
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except OSError: # no reply!
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# We got a NACK, which could be correct
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continue
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# store if success
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found.append(addr)
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return found
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# ----------------------------------------------------------------
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# ADC
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# ----------------------------------------------------------------
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def adc_configure(self, vref=0):
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"""Configure the Analog-to-Digital Converter"""
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report = bytearray(b"\x60" + b"\x00" * 63)
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report[5] = 1 << 7 | (vref & 0b111)
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self._hid_xfer(report)
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def adc_read(self, pin):
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"""Read from the Analog-to-Digital Converter"""
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resp = self._hid_xfer(b"\x10")
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return resp[49 + 2 * pin] << 8 | resp[48 + 2 * pin]
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# ----------------------------------------------------------------
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# DAC
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# ----------------------------------------------------------------
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def dac_configure(self, vref=0):
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"""Configure the Digital-to-Analog Converter"""
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report = bytearray(b"\x60" + b"\x00" * 63)
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report[3] = 1 << 7 | (vref & 0b111)
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self._hid_xfer(report)
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# pylint: disable=unused-argument
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def dac_write(self, pin, value):
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"""Write to the Digital-to-Analog Converter"""
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report = bytearray(b"\x60" + b"\x00" * 63)
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report[4] = 1 << 7 | (value & 0b11111)
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self._hid_xfer(report)
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# pylint: enable=unused-argument
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mcp2221 = MCP2221()
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