The PC <–usb--> uC protocol

The communication happens via a USB serial connection. The communication protocol is handled via fixed-length 9-byte packages packet_t, where the first byte is the header, which specifies the data format of the following 8 bytes, and the next 4 bytes (except for the error packets) are a timestamp in microseconds, leaving the last 4 bytes for data. In detail, the following data formats exist:

• data32_t , Data32bitPacket using the headers listed in Data32bitHeader

  [header: 1 byte][time: 4 byte][value: 4 byte]

• data_i2c_t , DataI2CPacket using the headers listed in DataI2CHeader

  [header : 1 byte][time: 4 byte][address: 7 bit][R/W: 1 bit][Reg Address: 1 byte][value: 2 byte]

• pin_t , PinPacket using the headers listed in PinHeader

  [header : 1 byte][time: 4 byte][Pin number: 1 byte][value: 1 byte][not used: 2 byte]

• config_t , ConfigPacket using the headers listed in ConfigMainHeader and the sub-headers in ConfigSubHeader

  [header : 1 byte][time: 4 byte][config header: 1 byte][value: 1 byte][not used: 2 byte]

• error_t , ErrorPacket using the headers listed in ErrorHeader

  [header : 1 byte][causing header: 1 byte][value: 4 byte][causing sub header: 1 byte][not used: 2 byte]