User Manual

MCP Series
Brushed DC Motor Controllers
MCP Series User Manual
63
2.2 Packet Serial Mode
2.2.1 Packet Serial Communications
Packet serial is a buffered bidirectional serial mode. Sophisticated instructions can be sent to the
controller. The basic command structures consist of an address byte, command byte, data bytes
and a CRC16 16bit checksum. The amount of data each command will send or receive can vary.
2.2.2 Address
Packet serial requires a unique address. With up to 8 addresses available you can control up to 8
motor controllers on the same TTL serial port when properly wired. Addresses range form 0x80
to 0x87
2.2.3 Packet Serial Baud Rate
When in serial mode or packet serial mode the baud rate can be changed to any baud rate
between 300 and 1000000bps
2.2.4 Packet Timeout
When sending a packet to the MCP, if there is a delay longer than 10ms between bytes being
received in a packet, the MCP will discard the entire packet. This will allow the packet buffer
to be cleared by simply adding a minimum 10ms delay before sending a new packet command
in the case of a communications error. This can usually be accommodated by having a 10ms
timeout when waiting for a reply from the MCP. If the reply times out the packet buffer will have
been cleared automatically.
2.2.5 Packet Acknowledgement
MCP will send an acknowledgment byte on write only packet commands that are valid. The value
sent back is 0xFF. If the packet was not valid for any reason no acknowledgement will be sent
back.