S912XEG128J2VAL
| Model | S912XEG128J2VAL |
| Description | IC,MICROCONTROLLER,16-BIT,CPU12 CPU,CMOS,QFP,112PIN,PLASTIC |
| PDF file | Total 1327 pages (File size: 7M) |
| Chip Manufacturer | ROCHESTER |
Chapter 16 Freescale’s Scalable Controller Area Network (S12MSCANV3)
7
6
5
4
3
2
1
0
R
CANE
W
Reset:
0
0
= Unimplemented
0
1
0
0
CLKSRC
LOOPB
LISTEN
BORM
WUPM
SLPAK
INITAK
0
1
Figure 16-5. MSCAN Control Register 1 (CANCTL1)
Read: Anytime
Write: Anytime when INITRQ = 1 and INITAK = 1, except CANE which is write once in normal and
anytime in special system operation modes when the MSCAN is in initialization mode (INITRQ = 1 and
INITAK = 1).
Table 16-3. CANCTL1 Register Field Descriptions
Field
7
CANE
6
CLKSRC
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;
Section 16.4.3.2, “Clock System,”
and
Section Figure 16-43., “MSCAN Clocking Scheme,”).
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 pin 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 16.4.4.4, “Listen-Only Mode”).
In addition, the error counters are frozen. Listen only mode supports
applications which require “hot plugging” or throughput analysis. The MSCAN is unable to transmit any
0 Normal operation
1 Listen only mode activated
Bus-Off Recovery Mode
— This bits configures the bus-off state recovery mode of the MSCAN. Refer to
Section 16.5.2, “Bus-Off Recovery,”
for details.
0 Automatic bus-off recovery (see Bosch CAN 2.0A/B protocol specification)
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
Section 16.4.5.4, “MSCAN Sleep Mode”).
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
Description
5
LOOPB
4
LISTEN
3
BORM
2
WUPM
MC9S12XE-Family Reference Manual Rev. 1.19
Freescale Semiconductor
611
Because of an order from the United States International Trade Commission, BGA-packaged product lines and part numbers indicated here currently are not
available from Freescale for import or sale in the United States prior to September 2010: S12XE products in 208 MAPBGA packages
Module Base 0x0001
+
