This is a compact and universal MSP430 USB CDC driver. Every effort has been made to make it portable.

• Initialising the USB hardware on the RP2040.
• Receiving and responding to setup packets from the host (PC). This determines which driver the OS will load.
• If the host is satisfied with the setup, then sending and receiving data packets may start.

  
  
  
  

  Pseudo code

DEFINE DEVICE-DECRIPTOR \ Device descriptor (18 bytes)
12 c, 01 c, 10 c, 01 c, ( 1.10 ) EF c, 02 c, 01 c, 40 c, 66 c, 66 c, ( 6666 )
10 c, 66 c, ( 6610 ) 00 c, 01 c, ( vsn 1.00 ) 00 c, 02 c, 00 c, 01 c,  align

DEFINE CONFIGURATION-DESCRIPTOR \ Configuration descriptor (9 or 75 bytes)
9 c,  2 c,  4B c,  0 c,  2 c,  1 c,  0 c,  80 c,  FA c, \ Maximum power = 500mA
8 c,  0B c,  0 c,  2 c,  2 c,  2 c,  1 c,  0 c,         \ Interface Association Descriptor - CDC 0
9 c,  4 c,  0 c,  0 c,  1 c,  2 c,  2 c,  1 c,  0 c,    \ Interface 1: Control - 1 - 0 -
5 c,  24 c,  0 c,  10 c,  1 c, ( CDC vsn 1.10 )         \ CDC Header functional
5 c,  24 c,  1 c,  0 c,  1 c,                           \ CDC Call management functional
4 c,  24 c,  2 c,  2 c,                                 \ CDC ACM functional ( two commands )
5 c,  24 c,  6 c,  0 c,  1 c,                           \ CDC Union functional ( one interface )
7 c,  5 c,  81 c,  3 c,  8 c,  0 c,  10 c,              \ Endpoint 1 IN descriptor
9 c,  4 c,  1 c,  0 c,  2 c,  0A c,  0 c,  0 c,  0 c,   \ Interface 2: DATA
7 c,  5 c,  82 c,  2 c,  40 c, 0 c,  0 c,               \ Endpoint 2 IN descriptor
7 c,  5 c,  3 c,  2 c,  40 c, 0 c,  0 c,  align         \ Endpoint 3 OUT descriptor