X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/blobdiff_plain/021c1242f9633bfdf2d83c55daec8df750577296..f5900b85957d39c2897f0d3eb5da486cbb392550:/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py diff --git a/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py b/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py index 39b1c07..8247006 100644 --- a/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py +++ b/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py @@ -1,6 +1,38 @@ +import os import time import hid +# Small values seem to help on some Windows setups +MCP2221_HID_DELAY = float(os.environ.get('BLINKA_MCP2221_HID_DELAY', 0)) + +# from the C driver +# http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz +# others (???) determined during driver developement +# pylint: disable=bad-whitespace +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 +# pylint: enable=bad-whitespace + class MCP2221: VID = 0x04D8 @@ -16,12 +48,14 @@ class MCP2221: self._hid = hid.device() self._hid.open(MCP2221.VID, MCP2221.PID) self._reset() + time.sleep(0.25) 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))) + time.sleep(MCP2221_HID_DELAY) if response: # return is 64 byte response report return self._hid.read(64) @@ -109,36 +143,34 @@ class MCP2221: #---------------------------------------------------------------- # 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] + 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) def _i2c_write(self, cmd, address, buffer, start=0, end=None): - if self._i2c_status(): + 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, 60) + chunk = min(end - start, MCP2221_MAX_I2C_DATA_LEN) # write out current chunk resp = self._hid_xfer(bytes([cmd, length & 0xFF, @@ -147,35 +179,82 @@ class MCP2221: 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 >= 5: + 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_status(): + if self._i2c_state() not in (RESP_I2C_WRITINGNOSTOP, 0): self._i2c_cancel() + end = end if end else len(buffer) length = end - start - retries = 0 + + # 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: - # 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 + for retry 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 + # move data into buffer chunk = min(end - start, 60) for i, k in enumerate(range(start, start+chunk)): @@ -205,12 +284,12 @@ class MCP2221: found = [] for addr in range(start, end+1): # try a write - self.i2c_writeto(addr, b'\x00') + try: + self.i2c_writeto(addr, b'\x00') + except RuntimeError: # no reply! + continue # store if success - if self._i2c_status() == 0x00: - found.append(addr) - # cancel and continue - self._i2c_cancel() + found.append(addr) return found #----------------------------------------------------------------