
Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
MC9S12XDP512 Data Sheet, Rev. 2.21
420
Freescale Semiconductor
10.1.2
Block Diagram
Figure 10-1. MSCAN Block Diagram
10.1.3
Features
The basic features of the MSCAN are as follows:
Implementation of the CAN protocol — Version 2.0A/B
— Standard and extended data frames
— Zero to eight bytes data length
— Programmable bit rate up to 1 Mbps1
— Support for remote frames
Five receive buffers with FIFO storage scheme
Three transmit buffers with internal prioritization using a “l(fā)ocal priority” concept
Flexible maskable identier lter supports two full-size (32-bit) extended identier lters, or four
16-bit lters, or eight 8-bit lters
Programmable wakeup functionality with integrated low-pass lter
Programmable loopback mode supports self-test operation
Programmable listen-only mode for monitoring of CAN bus
Programmable bus-off recovery functionality
Separate signalling and interrupt capabilities for all CAN receiver and transmitter error states
(warning, error passive, bus-off)
Programmable MSCAN clock source either bus clock or oscillator clock
1. Depending on the actual bit timing and the clock jitter of the PLL.
RXCAN
TXCAN
Receive/
Transmit
Engine
Message
Filtering
and
Buffering
Control
and
Status
Wake-Up Interrupt Req.
Errors Interrupt Req.
Receive Interrupt Req.
Transmit Interrupt Req.
CANCLK
Bus Clock
Conguration
Oscillator Clock
MUX
Presc.
Tq Clk
MSCAN
Low Pass Filter
Wake-Up
Registers