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         self._gp_config = [0x07] * 4  # "don't care" initial value
  58         for pin in range(4):
  59             self.gp_set_mode(pin, self.GP_GPIO)  # set to GPIO mode
  60             self.gpio_set_direction(pin, 1)  # set to INPUT
  61
  62     def _hid_xfer(self, report, response=True):
  63         """Perform HID Transfer"""
  64         # first byte is report ID, which =0 for MCP2221
  65         # remaing bytes = 64 byte report data
  66         # https://github.com/libusb/hidapi/blob/083223e77952e1ef57e6b77796536a3359c1b2a3/hidapi/hidapi.h#L185
  67         self._hid.write(b"\0" + report + b"\0" * (64 - len(report)))
  68         time.sleep(MCP2221_HID_DELAY)
  69         if response:
  70             # return is 64 byte response report
  71             return self._hid.read(64)
  72         return None
  73
  74     # ----------------------------------------------------------------
  75     # MISC
  76     # ----------------------------------------------------------------
  77     def gp_get_mode(self, pin):
  78         """Get Current Pin Mode"""
  79         val = self._hid_xfer(b"\x61")[22 + pin]
  80         print("0b{:08b}".format(val))
  81         return self._hid_xfer(b"\x61")[22 + pin] & 0x07
  82
  83     def gp_set_mode(self, pin, mode):
  84         """Set Current Pin Mode"""
  85         # already set to that mode?
  86         mode &= 0x07
  87         if mode == (self._gp_config[pin] & 0x07):
  88             return
  89         # update GP mode for pin
  90         self._gp_config[pin] = mode
  91         # empty report, this is safe since 0's = no change
  92         report = bytearray(b"\x60" + b"\x00" * 63)
  93         # set the alter GP flag byte
  94         report[7] = 0xFF
  95         # add GP setttings
  96         report[8] = self._gp_config[0]
  97         report[9] = self._gp_config[1]
  98         report[10] = self._gp_config[2]
  99         report[11] = self._gp_config[3]
 100         # and make it so
 101         self._hid_xfer(report)
 102
 103     def _pretty_report(self, register):
 104         report = self._hid_xfer(register)
 105         print("     0  1  2  3  4  5  6  7  8  9")
 106         index = 0
 107         for row in range(7):
 108             print("{} : ".format(row), end="")
 109             for _ in range(10):
 110                 print("{:02x} ".format(report[index]), end="")
 111                 index += 1
 112                 if index > 63:
 113                     break
 114             print()
 115
 116     def _status_dump(self):
 117         self._pretty_report(b"\x10")
 118
 119     def _sram_dump(self):
 120         self._pretty_report(b"\x61")
 121
 122     def _reset(self):
 123         self._hid_xfer(b"\x70\xAB\xCD\xEF", response=False)
 124         time.sleep(MCP2221_RESET_DELAY)
 125         start = time.monotonic()
 126         while time.monotonic() - start < 5:
 127             try:
 128                 self._hid.open(MCP2221.VID, MCP2221.PID)
 129             except OSError:
 130                 # try again
 131                 time.sleep(0.1)
 132                 continue
 133             return
 134         raise OSError("open failed")
 135
 136     # ----------------------------------------------------------------
 137     # GPIO
 138     # ----------------------------------------------------------------
 139     def gpio_set_direction(self, pin, mode):
 140         """Set Current GPIO Pin Direction"""
 141         if mode:
 142             # set bit 3 for INPUT
 143             self._gp_config[pin] |= 1 << 3
 144         else:
 145             # clear bit 3 for OUTPUT
 146             self._gp_config[pin] &= ~(1 << 3)
 147         report = bytearray(b"\x50" + b"\x00" * 63)  # empty set GPIO report
 148         offset = 4 * (pin + 1)
 149         report[offset] = 0x01  # set pin direction
 150         report[offset + 1] = mode  # to this
 151         self._hid_xfer(report)
 152
 153     def gpio_set_pin(self, pin, value):
 154         """Set Current GPIO Pin Value"""
 155         if value:
 156             # set bit 4
 157             self._gp_config[pin] |= 1 << 4
 158         else:
 159             # clear bit 4
 160             self._gp_config[pin] &= ~(1 << 4)
 161         report = bytearray(b"\x50" + b"\x00" * 63)  # empty set GPIO report
 162         offset = 2 + 4 * pin
 163         report[offset] = 0x01  # set pin value
 164         report[offset + 1] = value  # to this
 165         self._hid_xfer(report)
 166
 167     def gpio_get_pin(self, pin):
 168         """Get Current GPIO Pin Value"""
 169         resp = self._hid_xfer(b"\x51")
 170         offset = 2 + 2 * pin
 171         if resp[offset] == 0xEE:
 172             raise RuntimeError("Pin is not set for GPIO operation.")
 173         return resp[offset]
 174
 175     # ----------------------------------------------------------------
 176     # I2C
 177     # ----------------------------------------------------------------
 178     def _i2c_status(self):
 179         resp = self._hid_xfer(b"\x10")
 180         if resp[1] != 0:
 181             raise RuntimeError("Couldn't get I2C status")
 182         return resp
 183
 184     def _i2c_state(self):
 185         return self._i2c_status()[8]
 186
 187     def _i2c_cancel(self):
 188         resp = self._hid_xfer(b"\x10\x00\x10")
 189         if resp[1] != 0x00:
 190             raise RuntimeError("Couldn't cancel I2C")
 191         if resp[2] == 0x10:
 192             # bus release will need "a few hundred microseconds"
 193             time.sleep(0.001)
 194
 195     # pylint: disable=too-many-arguments
 196     def _i2c_write(self, cmd, address, buffer, start=0, end=None):
 197         if self._i2c_state() != 0x00:
 198             self._i2c_cancel()
 199
 200         end = end if end else len(buffer)
 201         length = end - start
 202         retries = 0
 203
 204         while (end - start) > 0:
 205             chunk = min(end - start, MCP2221_MAX_I2C_DATA_LEN)
 206             # write out current chunk
 207             resp = self._hid_xfer(
 208                 bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, address << 1])
 209                 + buffer[start : (start + chunk)]
 210             )
 211             # check for success
 212             if resp[1] != 0x00:
 213                 if resp[2] in (
 214                     RESP_I2C_START_TOUT,
 215                     RESP_I2C_WRADDRL_TOUT,
 216                     RESP_I2C_WRADDRL_NACK,
 217                     RESP_I2C_WRDATA_TOUT,
 218                     RESP_I2C_STOP_TOUT,
 219                 ):
 220                     raise RuntimeError("Unrecoverable I2C state failure")
 221                 retries += 1
 222                 if retries >= MCP2221_RETRY_MAX:
 223                     raise RuntimeError("I2C write error, max retries reached.")
 224                 time.sleep(0.001)
 225                 continue  # try again
 226             # yay chunk sent!
 227             while self._i2c_state() == RESP_I2C_PARTIALDATA:
 228                 time.sleep(0.001)
 229             start += chunk
 230             retries = 0
 231
 232         # check status in another loop
 233         for _ in range(MCP2221_RETRY_MAX):
 234             status = self._i2c_status()
 235             if status[20] & MASK_ADDR_NACK:
 236                 raise RuntimeError("I2C slave address was NACK'd")
 237             usb_cmd_status = status[8]
 238             if usb_cmd_status == 0:
 239                 break
 240             if usb_cmd_status == RESP_I2C_WRITINGNOSTOP and cmd == 0x94:
 241                 break  # this is OK too!
 242             if usb_cmd_status in (
 243                 RESP_I2C_START_TOUT,
 244                 RESP_I2C_WRADDRL_TOUT,
 245                 RESP_I2C_WRADDRL_NACK,
 246                 RESP_I2C_WRDATA_TOUT,
 247                 RESP_I2C_STOP_TOUT,
 248             ):
 249                 raise RuntimeError("Unrecoverable I2C state failure")
 250             time.sleep(0.001)
 251         else:
 252             raise RuntimeError("I2C write error: max retries reached.")
 253         # whew success!
 254
 255     def _i2c_read(self, cmd, address, buffer, start=0, end=None):
 256         if self._i2c_state() not in (RESP_I2C_WRITINGNOSTOP, 0):
 257             self._i2c_cancel()
 258
 259         end = end if end else len(buffer)
 260         length = end - start
 261
 262         # tell it we want to read
 263         resp = self._hid_xfer(
 264             bytes([cmd, length & 0xFF, (length >> 8) & 0xFF, (address << 1) | 0x01])
 265         )
 266
 267         # check for success
 268         if resp[1] != 0x00:
 269             raise RuntimeError("Unrecoverable I2C read failure")
 270
 271         # and now the read part
 272         while (end - start) > 0:
 273             for retry in range(MCP2221_RETRY_MAX):
 274                 # the actual read
 275                 resp = self._hid_xfer(b"\x40")
 276                 # check for success
 277                 if resp[1] == RESP_I2C_PARTIALDATA:
 278                     time.sleep(0.001)
 279                     continue
 280                 if resp[1] != 0x00:
 281                     raise RuntimeError("Unrecoverable I2C read failure")
 282                 if resp[2] == RESP_ADDR_NACK:
 283                     raise RuntimeError("I2C NACK")
 284                 if resp[3] == 0x00 and resp[2] == 0x00:
 285                     break
 286                 if resp[3] == RESP_READ_ERR:
 287                     time.sleep(0.001)
 288                     continue
 289                 if resp[2] in (RESP_READ_COMPL, RESP_READ_PARTIAL):
 290                     break
 291
 292             # move data into buffer
 293             chunk = min(end - start, 60)
 294             for i, k in enumerate(range(start, start + chunk)):
 295                 buffer[k] = resp[4 + i]
 296             start += chunk
 297
 298     # pylint: enable=too-many-arguments
 299
 300     def i2c_configure(self, baudrate=100000):
 301         """Configure I2C"""
 302         self._hid_xfer(
 303             bytes(
 304                 [
 305                     0x10,  # set parameters
 306                     0x00,  # don't care
 307                     0x00,  # no effect
 308                     0x20,  # next byte is clock divider
 309                     12000000 // baudrate - 3,
 310                 ]
 311             )
 312         )
 313
 314     def i2c_writeto(self, address, buffer, *, start=0, end=None):
 315         """Write data from the buffer to an address"""
 316         self._i2c_write(0x90, address, buffer, start, end)
 317
 318     def i2c_readfrom_into(self, address, buffer, *, start=0, end=None):
 319         """Read data from an address and into the buffer"""
 320         self._i2c_read(0x91, address, buffer, start, end)
 321
 322     def i2c_writeto_then_readfrom(
 323         self,
 324         address,
 325         out_buffer,
 326         in_buffer,
 327         *,
 328         out_start=0,
 329         out_end=None,
 330         in_start=0,
 331         in_end=None
 332     ):
 333         """Write data from buffer_out to an address and then
 334         read data from an address and into buffer_in
 335         """
 336         self._i2c_write(0x94, address, out_buffer, out_start, out_end)
 337         self._i2c_read(0x93, address, in_buffer, in_start, in_end)
 338
 339     def i2c_scan(self, *, start=0, end=0x79):
 340         """Perform an I2C Device Scan"""
 341         found = []
 342         for addr in range(start, end + 1):
 343             # try a write
 344             try:
 345                 self.i2c_writeto(addr, b"\x00")
 346             except RuntimeError:  # no reply!
 347                 continue
 348             # store if success
 349             found.append(addr)
 350         return found
 351
 352     # ----------------------------------------------------------------
 353     # ADC
 354     # ----------------------------------------------------------------
 355     def adc_configure(self, vref=0):
 356         """Configure the Analog-to-Digital Converter"""
 357         report = bytearray(b"\x60" + b"\x00" * 63)
 358         report[5] = 1 << 7 | (vref & 0b111)
 359         self._hid_xfer(report)
 360
 361     def adc_read(self, pin):
 362         """Read from the Analog-to-Digital Converter"""
 363         resp = self._hid_xfer(b"\x10")
 364         return resp[49 + 2 * pin] << 8 | resp[48 + 2 * pin]
 365
 366     # ----------------------------------------------------------------
 367     # DAC
 368     # ----------------------------------------------------------------
 369     def dac_configure(self, vref=0):
 370         """Configure the Digital-to-Analog Converter"""
 371         report = bytearray(b"\x60" + b"\x00" * 63)
 372         report[3] = 1 << 7 | (vref & 0b111)
 373         self._hid_xfer(report)
 374
 375     # pylint: disable=unused-argument
 376     def dac_write(self, pin, value):
 377         """Write to the Digital-to-Analog Converter"""
 378         report = bytearray(b"\x60" + b"\x00" * 63)
 379         report[4] = 1 << 7 | (value & 0b11111)
 380         self._hid_xfer(report)
 381
 382     # pylint: enable=unused-argument
 383
 384
 385 mcp2221 = MCP2221()