mc9s12xs128 Freescale Semiconductor, Inc, mc9s12xs128 Datasheet - Page 304

• Manufacturer Part Number: mc9s12xs128
• Description: Hcs12 Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Freescale’s Scalable Controller Area Network (S12MSCANV3)
1. Read: Anytime
304
Module Base + 0x0001
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1); CANE is write once
CLKSRC
LOOPB
LISTEN
WUPM
BORM
CANE
Field
7
6
5
4
3
2
Reset:
W
R
MSCAN Enable
0 MSCAN module is disabled
1 MSCAN module is enabled
MSCAN Clock Source — This bit defines the clock source for the MSCAN module (only for systems with a clock
generation module;
0 MSCAN clock source is the oscillator clock
1 MSCAN clock source is the bus clock
Loopback Self Test Mode — When this bit is set, the MSCAN performs an internal loopback which can be used
for self test operation. The bit stream output of the transmitter is fed back to the receiver internally. The RXCAN
input is ignored and the TXCAN output goes to the recessive state (logic 1). The MSCAN behaves as it does
normally when transmitting and treats its own transmitted message as a message received from a remote node.
In this state, the MSCAN ignores the bit sent during the ACK slot in the CAN frame acknowledge field to ensure
proper reception of its own message. Both transmit and receive interrupts are generated.
0 Loopback self test disabled
1 Loopback self test enabled
Listen Only Mode — This bit configures the MSCAN as a CAN bus monitor. When LISTEN is set, all valid CAN
messages with matching ID are received, but no acknowledgement or error frames are sent out (see
Section 11.4.4.4, “Listen-Only
applications which require “hot plugging” or throughput analysis. The MSCAN is unable to transmit any
messages when listen only mode is active.
0 Normal operation
1 Listen only mode activated
Bus-Off Recovery Mode — This bit configures the bus-off state recovery mode of the MSCAN. Refer to
Section 11.5.2, “Bus-Off
0 Automatic bus-off recovery (see Bosch CAN 2.0A/B protocol specification)
1 Bus-off recovery upon user request
Wake-Up Mode — If WUPE in CANCTL0 is enabled, this bit defines whether the integrated low-pass filter is
applied to protect the MSCAN from spurious wake-up (see
0 MSCAN wakes up on any dominant level on the CAN bus
1 MSCAN wakes up only in case of a dominant pulse on the CAN bus that has a length of T
CANE
0
7
= Unimplemented
CLKSRC
Figure 11-5. MSCAN Control Register 1 (CANCTL1)
Table 11-4. CANCTL1 Register Field Descriptions
6
0
Section 11.4.3.2, “Clock
Recovery,” for details.
S12XS Family Reference Manual, Rev. 1.10
LOOPB
Mode”). In addition, the error counters are frozen. Listen only mode supports
0
5
LISTEN
System,” and
4
1
Description
Section Figure 11-43., “MSCAN Clocking
BORM
Section 11.4.5.5, “MSCAN Sleep
0
3
WUPM
2
0
Access: User read/write
Freescale Semiconductor
SLPAK
0
1
wup
Mode”).
Scheme,”).
INITAK
0
1
(1)