src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py

   1 """Chip Definition for MCP2221"""
   2
   3 import os
   4 import time
   5 import hid
   6
   7 # Here if you need it
   8 MCP2221_HID_DELAY = float(os.environ.get("BLINKA_MCP2221_HID_DELAY", 0))
   9 # Use to set delay between reset and device reopen
  10 MCP2221_RESET_DELAY = float(os.environ.get("BLINKA_MCP2221_RESET_DELAY", 0.5))
  11
  12 # from the C driver
  13 # http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz
  14 # others (???) determined during driver developement
  15 # pylint: disable=bad-whitespace
  16 RESP_ERR_NOERR = 0x00
  17 RESP_ADDR_NACK = 0x25
  18 RESP_READ_ERR = 0x7F
  19 RESP_READ_COMPL = 0x55
  20 RESP_READ_PARTIAL = 0x54  # ???
  21 RESP_I2C_IDLE = 0x00
  22 RESP_I2C_START_TOUT = 0x12
  23 RESP_I2C_RSTART_TOUT = 0x17
  24 RESP_I2C_WRADDRL_TOUT = 0x23
  25 RESP_I2C_WRADDRL_WSEND = 0x21
  26 RESP_I2C_WRADDRL_NACK = 0x25
  27 RESP_I2C_WRDATA_TOUT = 0x44
  28 RESP_I2C_RDDATA_TOUT = 0x52
  29 RESP_I2C_STOP_TOUT = 0x62
  30
  31 RESP_I2C_MOREDATA = 0x43  # ???
  32 RESP_I2C_PARTIALDATA = 0x41  # ???
  33 RESP_I2C_WRITINGNOSTOP = 0x45  # ???
  34
  35 MCP2221_RETRY_MAX = 50
  36 MCP2221_MAX_I2C_DATA_LEN = 60
  37 MASK_ADDR_NACK = 0x40
  38 # pylint: enable=bad-whitespace
  39
  40
  41 class MCP2221:
  42     """MCP2221 Device Class Definition"""
  43
  44     VID = 0x04D8
  45     PID = 0x00DD
  46
  47     GP_GPIO = 0b000
  48     GP_DEDICATED = 0b001
  49     GP_ALT0 = 0b010
  50     GP_ALT1 = 0b011
  51     GP_ALT2 = 0b100
  52
  53     def __init__(self):
  54         self._hid = hid.device()
  55         self._hid.open(MCP2221.VID, MCP2221.PID)
  56         self._reset()
  57
  58     def _hid_xfer(self, report, response=True):
  59         """Perform HID Transfer"""
  60         # first byte is report ID, which =0 for MCP2221
  61         # remaing bytes = 64 byte report data
  62         # https://github.com/libusb/hidapi/blob/083223e77952e1ef57e6b77796536a3359c1b2a3/hidapi/hidapi.h#L185
  63         self._hid.write(b"\0" + report + b"\0" * (64 - len(report)))
  64         time.sleep(MCP2221_HID_DELAY)
  65         if response:
  66             # return is 64 byte response report
  67             return self._hid.read(64)
  68         return None
  69
  70     # ----------------------------------------------------------------
  71     # MISC
  72     # ----------------------------------------------------------------
  73     def gp_get_mode(self, pin):
  74         """Get Current Pin Mode"""
  75         return self._hid_xfer(b"\x61")[22 + pin] & 0x07
  76
  77     def gp_set_mode(self, pin, mode):
  78         """Set Current Pin Mode"""
  79         # get current settings
  80         current = self._hid_xfer(b"\x61")
  81         # empty report, this is safe since 0's = no change
  82         report = bytearray(b"\x60" + b"\x00" * 63)
  83         # set the alter GP flag byte
  84         report[7] = 0xFF
  85         # each pin can be set individually
  86         # but all 4 get set at once, so we need to
  87         # transpose current settings
  88         report[8] = current[22]  # GP0
  89         report[9] = current[23]  # GP1
  90         report[10] = current[24]  # GP2
  91         report[11] = current[25]  # GP3
  92         # then change only the one
  93         report[8 + pin] = mode & 0x07
  94         # and make it so
  95         self._hid_xfer(report)
  96
  97     def _pretty_report(self, register):
  98         report = self._hid_xfer(register)
  99         print("     0  1  2  3  4  5  6  7  8  9")
 100         index = 0
 101         for row in range(7):
 102             print("{} : ".format(row), end="")
 103             for _ in range(10):
 104                 print("{:02x} ".format(report[index]), end="")
 105                 index += 1
 106                 if index > 63:
 107                     break
 108             print()
 109
 110     def _status_dump(self):
 111         self._pretty_report(b"\x10")
 112
 113     def _sram_dump(self):
 114         self._pretty_report(b"\x61")
 115
 116     def _reset(self):
 117         self._hid_xfer(b"\x70\xAB\xCD\xEF", response=False)
 118         time.sleep(MCP2221_RESET_DELAY)
 119         start = time.monotonic()
 120         while time.monotonic() - start < 5:
 121             try:
 122                 self._hid.open(MCP2221.VID, MCP2221.PID)
 123             except OSError:
 124                 # try again
 125                 time.sleep(0.1)
 126                 continue
 127             return
 128         raise OSError("open failed")
 129
 130     # ----------------------------------------------------------------
 131     # GPIO
 132     # ----------------------------------------------------------------
 133     def gpio_set_direction(self, pin, mode):
 134         """Set Current GPIO Pin Direction"""
 135         report = bytearray(b"\x50" + b"\x00" * 63)  # empty set GPIO report
 136         offset = 4 * (pin + 1)
 137         report[offset] = 0x01  # set pin direction
 138         report[offset + 1] = mode  # to this
 139         self._hid_xfer(report)
 140
 141     def gpio_set_pin(self, pin, value):
 142         """Set Current GPIO Pin Value"""
 143         report = bytearray(b"\x50" + b"\x00" * 63)  # empty set GPIO report
 144         offset = 2 + 4 * pin
 145         report[offset] = 0x01  # set pin value
 146         report[offset + 1] = value  # to this
 147         self._hid_xfer(report)
 148
 149     def gpio_get_pin(self, pin):
 150         """Get Current GPIO Pin Value"""
 151         resp = self._hid_xfer(b"\x51")
 152         offset = 2 + 2 * pin
 153         if resp[offset] == 0xEE:
 154             raise RuntimeError("Pin is not set for GPIO operation.")
 155         return resp[offset]
 156
 157     # ----------------------------------------------------------------
 158     # I2C
 159     # ----------------------------------------------------------------
 160     def _i2c_status(self):
 161         resp = self._hid_xfer(b"\x10")
 162         if resp[1] != 0:
 163             raise RuntimeError("Couldn't get I2C status")
 164         return resp
 165
 166     def _i2c_state(self):
 167         return self._i2c_status()[8]
 168
 169     def _i2c_cancel(self):
 170         resp = self._hid_xfer(b"\x10\x00\x10")
 171         if resp[1] != 0x00:
 172             raise RuntimeError("Couldn't cancel I2C")
 173         if resp[2] == 0x10:
 174             # bus release will need "a few hundred microseconds"
 175             time.sleep(0.001)
 176
 177     # pylint: disable=too-many-arguments
 178     def _i2c_write(self, cmd, address, buffer, start=0, end=None):
 179         if self._i2c_state() != 0x00:
 180             self._i2c_cancel()
 181
 182         end = end if end else len(buffer)
 183         length = end - start
 184         retries = 0
 185
 186         while (end - start) > 0:
 187             chunk = min(end - start, MCP2221_MAX_I2C_DATA_LEN)
 188             # write out current chunk
 189             resp = self._hid_xfer(
 190                 bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, address << 1])
 191                 + buffer[start : (start + chunk)]
 192             )
 193             # check for success
 194             if resp[1] != 0x00:
 195                 if resp[2] in (
 196                     RESP_I2C_START_TOUT,
 197                     RESP_I2C_WRADDRL_TOUT,
 198                     RESP_I2C_WRADDRL_NACK,
 199                     RESP_I2C_WRDATA_TOUT,
 200                     RESP_I2C_STOP_TOUT,
 201                 ):
 202                     raise RuntimeError("Unrecoverable I2C state failure")
 203                 retries += 1
 204                 if retries >= MCP2221_RETRY_MAX:
 205                     raise RuntimeError("I2C write error, max retries reached.")
 206                 time.sleep(0.001)
 207                 continue  # try again
 208             # yay chunk sent!
 209             while self._i2c_state() == RESP_I2C_PARTIALDATA:
 210                 time.sleep(0.001)
 211             start += chunk
 212             retries = 0
 213
 214         # check status in another loop
 215         for _ in range(MCP2221_RETRY_MAX):
 216             status = self._i2c_status()
 217             if status[20] & MASK_ADDR_NACK:
 218                 raise RuntimeError("I2C slave address was NACK'd")
 219             usb_cmd_status = status[8]
 220             if usb_cmd_status == 0:
 221                 break
 222             if usb_cmd_status == RESP_I2C_WRITINGNOSTOP and cmd == 0x94:
 223                 break  # this is OK too!
 224             if usb_cmd_status in (
 225                 RESP_I2C_START_TOUT,
 226                 RESP_I2C_WRADDRL_TOUT,
 227                 RESP_I2C_WRADDRL_NACK,
 228                 RESP_I2C_WRDATA_TOUT,
 229                 RESP_I2C_STOP_TOUT,
 230             ):
 231                 raise RuntimeError("Unrecoverable I2C state failure")
 232             time.sleep(0.001)
 233         else:
 234             raise RuntimeError("I2C write error: max retries reached.")
 235         # whew success!
 236
 237     def _i2c_read(self, cmd, address, buffer, start=0, end=None):
 238         if self._i2c_state() not in (RESP_I2C_WRITINGNOSTOP, 0):
 239             self._i2c_cancel()
 240
 241         end = end if end else len(buffer)
 242         length = end - start
 243
 244         # tell it we want to read
 245         resp = self._hid_xfer(
 246             bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, (address << 1) | 0x01])
 247         )
 248
 249         # check for success
 250         if resp[1] != 0x00:
 251             raise RuntimeError("Unrecoverable I2C read failure")
 252
 253         # and now the read part
 254         while (end - start) > 0:
 255             for retry in range(MCP2221_RETRY_MAX):
 256                 # the actual read
 257                 resp = self._hid_xfer(b"\x40")
 258                 # check for success
 259                 if resp[1] == RESP_I2C_PARTIALDATA:
 260                     time.sleep(0.001)
 261                     continue
 262                 if resp[1] != 0x00:
 263                     raise RuntimeError("Unrecoverable I2C read failure")
 264                 if resp[2] == RESP_ADDR_NACK:
 265                     raise RuntimeError("I2C NACK")
 266                 if resp[3] == 0x00 and resp[2] == 0x00:
 267                     break
 268                 if resp[3] == RESP_READ_ERR:
 269                     time.sleep(0.001)
 270                     continue
 271                 if resp[2] in (RESP_READ_COMPL, RESP_READ_PARTIAL):
 272                     break
 273
 274             # move data into buffer
 275             chunk = min(end - start, 60)
 276             for i, k in enumerate(range(start, start + chunk)):
 277                 buffer[k] = resp[4 + i]
 278             start += chunk
 279
 280     # pylint: enable=too-many-arguments
 281
 282     def i2c_configure(self, baudrate=100000):
 283         """Configure I2C"""
 284         self._hid_xfer(
 285             bytes(
 286                 [
 287                     0x10,  # set parameters
 288                     0x00,  # don't care
 289                     0x00,  # no effect
 290                     0x20,  # next byte is clock divider
 291                     12000000 // baudrate - 3,
 292                 ]
 293             )
 294         )
 295
 296     def i2c_writeto(self, address, buffer, *, start=0, end=None):
 297         """Write data from the buffer to an address"""
 298         self._i2c_write(0x90, address, buffer, start, end)
 299
 300     def i2c_readfrom_into(self, address, buffer, *, start=0, end=None):
 301         """Read data from an address and into the buffer"""
 302         self._i2c_read(0x91, address, buffer, start, end)
 303
 304     def i2c_writeto_then_readfrom(
 305         self,
 306         address,
 307         out_buffer,
 308         in_buffer,
 309         *,
 310         out_start=0,
 311         out_end=None,
 312         in_start=0,
 313         in_end=None
 314     ):
 315         """Write data from buffer_out to an address and then
 316         read data from an address and into buffer_in
 317         """
 318         self._i2c_write(0x94, address, out_buffer, out_start, out_end)
 319         self._i2c_read(0x93, address, in_buffer, in_start, in_end)
 320
 321     def i2c_scan(self, *, start=0, end=0x79):
 322         """Perform an I2C Device Scan"""
 323         found = []
 324         for addr in range(start, end + 1):
 325             # try a write
 326             try:
 327                 self.i2c_writeto(addr, b"\x00")
 328             except RuntimeError:  # no reply!
 329                 continue
 330             # store if success
 331             found.append(addr)
 332         return found
 333
 334     # ----------------------------------------------------------------
 335     # ADC
 336     # ----------------------------------------------------------------
 337     def adc_configure(self, vref=0):
 338         """Configure the Analog-to-Digital Converter"""
 339         report = bytearray(b"\x60" + b"\x00" * 63)
 340         report[5] = 1 << 7 | (vref & 0b111)
 341         self._hid_xfer(report)
 342
 343     def adc_read(self, pin):
 344         """Read from the Analog-to-Digital Converter"""
 345         resp = self._hid_xfer(b"\x10")
 346         return resp[49 + 2 * pin] << 8 | resp[48 + 2 * pin]
 347
 348     # ----------------------------------------------------------------
 349     # DAC
 350     # ----------------------------------------------------------------
 351     def dac_configure(self, vref=0):
 352         """Configure the Digital-to-Analog Converter"""
 353         report = bytearray(b"\x60" + b"\x00" * 63)
 354         report[3] = 1 << 7 | (vref & 0b111)
 355         self._hid_xfer(report)
 356
 357     # pylint: disable=unused-argument
 358     def dac_write(self, pin, value):
 359         """Write to the Digital-to-Analog Converter"""
 360         report = bytearray(b"\x60" + b"\x00" * 63)
 361         report[4] = 1 << 7 | (value & 0b11111)
 362         self._hid_xfer(report)
 363
 364     # pylint: enable=unused-argument
 365
 366
 367 mcp2221 = MCP2221()