Freescale’s Scalable Controller Area Network (S12MSCANV3)
S12XS Family Reference Manual, Rev. 1.13
306
Freescale Semiconductor
11.3.2.4
MSCAN Bus Timing Register 1 (CANBTR1)
The CANBTR1 register configures various CAN bus timing parameters of the MSCAN module.
Table 11-7. Baud Rate Prescaler
BRP5
BRP4
BRP3
BRP2
BRP1
BRP0
Prescaler value (P)
0
0
0
0
0
0
1
0
0
0
0
0
1
2
0
0
0
0
1
0
3
0
0
0
0
1
1
4
:
:
:
:
:
:
:
1
1
1
1
1
1
64
Module Base + 0x0003
Access: User read/write
(1)
1. Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
7
6
5
4
3
2
1
0
R
SAMP
TSEG22
TSEG21
TSEG20
TSEG13
TSEG12
TSEG11
TSEG10
W
Reset:
0
0
0
0
0
0
0
0
Figure 11-7. MSCAN Bus Timing Register 1 (CANBTR1)
Table 11-8. CANBTR1 Register Field Descriptions
Field
Description
7
SAMP
Sampling — This bit determines the number of CAN bus samples taken per bit time.
0 One sample per bit.
1 Three samples per bit
(1)
.
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).
1. In this case, PHASE_SEG1 must be at least 2 time quanta (Tq).
6-4
TSEG2[2:0]
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
). Time segment 2 (TSEG2) values are programmable as shown in
.
3-0
TSEG1[3:0]
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
). Time segment 1 (TSEG1) values are programmable as shown in
.
Содержание MC9S12XS128
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Страница 58: ...Device Overview S12XS Family S12XS Family Reference Manual Rev 1 13 58 Freescale Semiconductor ...
Страница 150: ...Memory Mapping Control S12XMMCV4 S12XS Family Reference Manual Rev 1 13 150 Freescale Semiconductor ...
Страница 168: ...Interrupt S12XINTV2 S12XS Family Reference Manual Rev 1 13 168 Freescale Semiconductor ...
Страница 194: ...Background Debug Module S12XBDMV2 S12XS Family Reference Manual Rev 1 13 194 Freescale Semiconductor ...
Страница 364: ...Periodic Interrupt Timer S12PIT24B4CV1 S12XS Family Reference Manual Rev 1 13 364 Freescale Semiconductor ...
Страница 396: ...Pulse Width Modulator S12PWM8B8CV1 S12XS Family Reference Manual Rev 1 13 396 Freescale Semiconductor ...
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