mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 324

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Freescale’s Controller Area Network (MSCANV1)
15.3.4
The CANBTR1 register configures various CAN bus timing parameters of the MSCAN module.
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
1
15-8
TSEG2[2:0]
TSEG1[3:0]
In this case, PHASE_SEG1 must be at least 2 time quanta (Tq).
SAMP
Field
6:4
3:0
7
Reset:
W
R
BRP5
MSCAN Bus Timing Register 1 (CANBTR1)
Sampling — This bit determines the number of CAN bus samples taken per bit time.
0 One sample per bit.
1 Three samples per bit
If SAMP = 0, the resulting bit value is equal to the value of the single bit positioned at the sample point. If
SAMP = 1, the resulting bit value is determined by using majority rule on the three total samples. For higher bit
rates, it is recommended that only one sample is taken per bit time (SAMP = 0).
Time Segment 2 — Time segments within the bit time fix the number of clock cycles per bit time and the location
of the sample point (see
Table
Time Segment 1 — Time segments within the bit time fix the number of clock cycles per bit time and the location
of the sample point (see
Table
0
0
0
0
1
:
SAMP
0
7
15-7.
15-8.
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
BRP4
0
0
0
0
1
:
Figure 15-6. MSCAN Bus Timing Register 1 (CANBTR1)
TSEG22
Table 15-6. CANBTR1 Register Field Descriptions
BRP3
6
0
0
0
0
0
1
:
Table 15-5. Baud Rate Prescaler
1
Figure
Figure
.
BRP2
TSEG21
0
0
0
0
1
:
15-42). Time segment 2 (TSEG2) values are programmable as shown in
15-42). Time segment 1 (TSEG1) values are programmable as shown in
0
5
BRP1
0
0
1
1
1
:
TSEG20
4
0
BRP0
Description
0
1
0
1
1
:
TSEG13
0
3
Prescaler value (P)
TSEG12
64
2
0
1
2
3
4
:
TSEG11
Freescale Semiconductor
0
1
TSEG10
0
0