usbd(cdc): add support for line break

hoihu · hoihu · commit d32759cc8e71 · 2023-09-03T15:32:24.000+02:00
and add a callback to it
diff --git a/micropython/usbd/cdc.py b/micropython/usbd/cdc.py
@@ -86,6 +86,8 @@ def __init__(self, _):
         self.stop_bits = 0
         self.parity = 0
         self.data_bits = None
+        self.break_cb = None   # callback for break condition
+
         self.line_coding_state = bytearray(7)
 
     def get_itf_descriptor(self, num_eps, itf_idx, str_idx):
@@ -157,6 +159,10 @@ def handle_interface_control_xfer(self, stage, request):
                     self.dtr = bool(wValue & 0x1)
                     self.rts = bool(wValue & 0x2)
                     return b""
+                elif bRequest == _SEND_BREAK_REQ:
+                    if self.break_cb:
+                        self.break_cb(wValue)
+                    return b""
 
         if stage == STAGE_DATA:
             if req_type == REQ_TYPE_CLASS:
@@ -167,6 +173,11 @@ def handle_interface_control_xfer(self, stage, request):
                         '<LBBB', self.line_coding_state)
         return True
 
+    def set_break_cb(self, cb):
+        # sets a callback for the break condition
+        # callback must have one parameter (duration in msec)
+        self.break_cb = cb
+
     def get_control_line(self):
         return self.dtr, self.rts
 
