
CAN Module
Mitsubishi microcomputers
M16C / 6N0 / 6N1 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
171
CAN Module
The CAN (Controller Area Network) module for the M16C/6N group of microcomputers is a communication
controller implementing the CAN 2.0B protocol as defined in the BOSCH specification. The M16C/6N0
group contains two Full CAN modules and the M16C/6N1 group contains one Full CAN module which can
transmit and receive messages in both standard (11 bit) ID and extended (29 bit) ID formats.
Figure 1.20.1 shows a block diagram of the CAN module.
External CAN bus driver and receiver are required.
Figure 1.20.1. Block diagram of the CAN module
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 CANi global mask register, the CANi local mask A register, or the
CANi local mask B 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:
CANi wake up interrupt is generated by a message from the CAN bus.
Interrupt generation function: The interrupt events are provided by the CAN module. CANi successful reception
interrupt, CANi successful transmission interrupt, CAN0/1 error interrupt, and
CAN0/1 wake up interrupt.
Note: i = 0, 1. Channel CAN1 is not available for M16C/6N1 group.
CANi Configu ration
Register
CANi Con trol
Register
CANi Extended ID
Register
Note: i = 0, 1. Channel CAN1 is not available for M16C/6N1group.
Interrupt
Generation
Function
Message Box
slots 0 to 15
Message ID
DLC
Message Data
Tim e Stamp
CTX
CRX
CANi Global Mask
Register
CANi Local Mask A
Register
CANi Local Mask B
Register
CANi RecSuc Int
CANi TrmSuc Int
CANi Error Int
CANi Wake Up Int
Data Bus
CANi Message
Control
Register 0 to 15
CAN Time Stamp
Register
16 Bit Timer
Acceptance Filter
slots 0 to 15
Protocol
Controller
Wake Up
Function
CANi Slot Status
Register
CANi Interrupt
Co ntrol Register
CANi Status
Register
CANi Receive Error
Count Register
CANi Transmit Error
Count Register