change MCP2221 reset behavior

[Adafruit_Blinka-hackapet.git] / 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 bd44474d46faa3498692880ba07202753f766f9a..3cfb46be33e4c9358959fece3abca9ba5542e4c1 100644 (file)
--- a/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
+++ b/src/adafruit_blinka/microcontroller/mcp2221/mcp2221.py
@@ -1,6 +1,12 @@
+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))
+# Windows also seems to want some time after a reset
+MCP2221_RESET_DELAY = float(os.environ.get('BLINKA_MCP2221_RESET_DELAY', 0.1))
+
 # from the C driver
 # http://ww1.microchip.com/downloads/en/DeviceDoc/mcp2221_0_1.tar.gz
 # others (???) determined during driver developement
@@ -44,13 +50,13 @@ 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)
@@ -100,6 +106,7 @@ class MCP2221:
 
     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:
@@ -279,12 +286,12 @@ 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
 
     #----------------------------------------------------------------