Renesas 16-bit single-chip microcomputer Manual Do Utilizador

Rev.1.02    Jul 01, 2005    page 198 of 314
REJ09B0126-0102

M16C/6N Group (M16C/6NL, M16C/6NN)

18. CAN Module

This document is under development and its contents are subject to change.

The CAN (Controller Area Network) module for the M16C/6N Group (M16C/6NL, M16C/6NN) of microcomputers

is a communication controller implementing the CAN 2.0B protocol. The M16C/6N Group (M16C/6NL,

M16C/6NN) contains one CAN module which can transmit and receive messages in both standard (11-bit)

ID and extended (29-bit) ID formats.

Figure 18.1 shows a block diagram of the CAN module.

External CAN bus driver and receiver are required.

CTX/CRX:

CAN I/O pins.

Protocol controller:

This controller handles the bus arbitration and the CAN protocol services, i.e. bit

timing, stuffing, error status etc.

Message box:

This memory block consists of 16 slots that can be configured either as transmitter

or receiver. Each slot contains an individual ID, data length code, a data field

(8 bytes) and a time stamp.

Acceptance filter:

This block performs filtering operation for received messages. For the filtering

operation, the C0GMR register, the C0LMAR register, or the C0LMBR register is

used.

16 bit timer:

Used for the time stamp function. When the received message is stored in the

message memory, the timer value is stored as a time stamp.

Wake-up function:

CAN0 wake-up interrupt request is generated by a message from the CAN bus.

Interrupt generation function: The interrupt requests are generated by the CAN module. CAN0 successful

reception interrupt, CAN0 successful transmission interrupt, CAN0 error interrupt

and CAN0 wake-up interrupt.

j = 0 to 15