raspbot是一个基于ROS的小车。它采用树莓派4B作为微型电脑，STM32F103C8T6作为下位机控制小车移动，两者之间依靠串口进行通信。
/****************************************************************************************
* Serial Protocol *
* *
* ,------+------+------+-------+- - - - - -+- - - - - -+- - - - -+- - - - -+ *
* | Type | SOF | LEN | CRC | DPKG | DPKG | .... | CRC | *
* ,------+------+------+-------+-----------+-----------+---------+---------+ *
* | size | 2 | 1 | 1 | ... | ... | ... | 2 | *
* '----- +------+------+-------+- - - - - -+- - - - - -+- - - - -+- - - - -+ *
* SOF ......... start of frame, 2 bytes *
* LEN ......... number of data package in the frame *
* CRC ......... Head of Frame's cyclic redundancy check *
* DPKG ......... data package,include DATA_TAG,DATA *
* CRC ......... DATA cyclic redundancy check *
* *
* *
* ,------+--------------+---------+---------+--------+ *
* | Type | element | size | offset | seq | *
* ,------,--------------+---------+---------+--------+ *
* | | frame head1 | 1 BYTE | 0 | 1 | *
* | SOF ,--------------+---------+---------+--------+ *
* | | frame head2 | 1 BYTE | 1 | 2 | *
* ,------,--------------+---------+---------+--------+ *
* | LEN | | 1 BYTE | 2 | 3 | *
* ,------,--------------+---------+---------+--------+ *
* | CRC | | 1 BYTES | 3 | 4 | *
* ,------,--------------+---------+---------+--------+ *
* | | DATA_TAG | 1 BYTE | 4 | 5 | *
* | DPKG ,--------------+---------+---------+--------+ *
* | | DATA | n BYTES | 5 | 6 | *
* ,---------------------+---------+---------+--------+ *
* | CRC | | 2 BYTES | 4+n | n+5 | *
* '------'--------------+---------+---------+--------+ *
* *
* Endian: Little-Endian *
*****************************************************************************************/