mc9s12xd256 Freescale Semiconductor, Inc, mc9s12xd256 Datasheet - Page 428

• Manufacturer Part Number: mc9s12xd256
• Description: Hcs12x Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Chapter 10 Freescale’s Scalable Controller Area Network (S12MSCANV3)
10.3.2.3
The CANBTR0 register configures various CAN bus timing parameters of the MSCAN module.
Read: Anytime
Write: Anytime in initialization mode (INITRQ = 1 and INITAK = 1)
428
SJW[1:0]
BRP[5:0]
SLPAK
INITAK
Field
Field
7:6
5:0
1
0
Reset:
W
R
Sleep Mode Acknowledge — This flag indicates whether the MSCAN module has entered sleep mode (see
Section 10.4.5.4, “MSCAN Sleep
Sleep mode is active when SLPRQ = 1 and SLPAK = 1. Depending on the setting of WUPE, the MSCAN will
clear the flag if it detects activity on the CAN bus while in sleep mode.
0 Running — The MSCAN operates normally
1 Sleep mode active — The MSCAN has entered sleep mode
Initialization Mode Acknowledge — This flag indicates whether the MSCAN module is in initialization mode
(see
mode request. Initialization mode is active when INITRQ = 1 and INITAK = 1. The registers CANCTL1,
CANBTR0, CANBTR1, CANIDAC, CANIDAR0–CANIDAR7, and CANIDMR0–CANIDMR7 can be written only by
the CPU when the MSCAN is in initialization mode.
0 Running — The MSCAN operates normally
1 Initialization mode active — The MSCAN has entered initialization mode
Synchronization Jump Width — The synchronization jump width defines the maximum number of time quanta
(Tq) clock cycles a bit can be shortened or lengthened to achieve resynchronization to data transitions on the
CAN bus (see
Baud Rate Prescaler — These bits determine the time quanta (Tq) clock which is used to build up the bit timing
(see
MSCAN Bus Timing Register 0 (CANBTR0)
SJW1
Section 10.4.5.5, “MSCAN Initialization
Table
0
7
SJW1
10-5).
0
0
1
1
Table 10-2. CANCTL1 Register Field Descriptions (continued)
Table
Figure 10-6. MSCAN Bus Timing Register 0 (CANBTR0)
Table 10-4. Synchronization Jump Width
SJW0
Table 10-3. CANBTR0 Register Field Descriptions
0
6
10-4).
MC9S12XDP512 Data Sheet, Rev. 2.17
BRP5
0
Mode”). It is used as a handshake flag for the SLPRQ sleep mode request.
5
SJW0
0
1
0
1
Mode”). It is used as a handshake flag for the INITRQ initialization
BRP4
0
4
Description
Description
BRP3
Synchronization Jump Width
3
0
2 Tq clock cycles
3 Tq clock cycles
4 Tq clock cycles
1 Tq clock cycle
BRP2
0
2
Freescale Semiconductor
BRP1
0
1
BRP0
0
0