Quote:
Originally Posted by flameout
Not knowing anything about LIN... I'll assume an essentially perfect bit packing for minimal operation.
4 motor controllers * 8 bits/controller/cycle = 312 Hz control
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You don't send 8-bit LIN commands.
http://en.wikipedia.org/wiki/Local_Interconnect_Network
LIN, like CAN, is a message based protocol, with generally lower bus speeds than CAN and significantly simpler implementation. Unlike CAN, LIN has a bus master which is in charge of bus arbitration and scheduling. Vehicles generally use it to connect slave IO modules to a central ECU, for example to connect buttons on a steering wheel to a body control module, where the button modules act as LIN slaves. The smarter LIN bus masters are then connected to the full CAN busses, CAN being a faster and master-less bus which is often used for sending many messages very fast.
But, you communicate by sending message frames. Frames consist of various header information fields (including an ID) and 2,4 or 8 bytes of data.
It would be just fine for 50hz motor updates. It's really easy to wire, as it dosen't care about splits or segments and can run at rather long wire lengths (for FRC use) with no issues, it uses a single wire with 12v signal voltage, and is implemented using UART hardware, meaning a simple level shifter is all you need to use the RS-232 port to speak LIN.