X-3D-BL ResearchPilot User's Manual - Ascending Technologies

};
4.2.2 Command input
X-3D-BL ResearchPilot User’s Manual
All packets send to the X-3D ResearchPilot have the following frame format:
Startbyte 1: >
Startbyte 2: ∗
Startbyte 3: >
Length of dat in bytes (high byte)
Length of data in bytes (low byte)
DATA
CRC16 of data (high byte)
CRC16 of data (low byte)
Length and CRC16 are unsigned short types.
For calculating the CRC16 of a packet you can use the following algorithm:
//update crc with data
unsigned short crc_update(unsigned short crc,unsigned char data)
{
data ˆ= (crc & 0xff);
data ˆ= data 8)&0xff))
ˆ (unsigned char )(data >> 4) ˆ ((unsigned short )data