Freescale’s Scalable Controller Area Network (S12MSCANV3)
S12XS Family Reference Manual, Rev. 1.13
348
Freescale Semiconductor
11.5
Initialization/Application Information
11.5.1
MSCAN initialization
The procedure to initially start up the MSCAN module out of reset is as follows:
1. Assert CANE
2. Write to the configuration registers in initialization mode
3. Clear INITRQ to leave initialization mode
If the configuration of registers which are only writable in initialization mode shall be changed:
1. Bring the module into sleep mode by setting SLPRQ and awaiting SLPAK to assert after the CAN
bus becomes idle.
2. Enter initialization mode: assert INITRQ and await INITAK
3. Write to the configuration registers in initialization mode
4. Clear INITRQ to leave initialization mode and continue
11.5.2
Bus-Off Recovery
The bus-off recovery is user configurable. The bus-off state can either be left automatically or on user
request.
For reasons of backwards compatibility, the MSCAN defaults to automatic recovery after reset. In this
case, the MSCAN will become error active again after counting 128 occurrences of 11 consecutive
recessive bits on the CAN bus (see the Bosch CAN 2.0 A/B specification for details).
If the MSCAN is configured for user request (BORM set in MSCAN Control Register 1 (CANCTL1)), the
recovery from bus-off starts after both independent events have become true:
•
128 occurrences of 11 consecutive recessive bits on the CAN bus have been monitored
•
BOHOLD in MSCAN Miscellaneous Register (CANMISC) has been cleared by the user
These two events may occur in any order.
Содержание MC9S12XS128
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Страница 58: ...Device Overview S12XS Family S12XS Family Reference Manual Rev 1 13 58 Freescale Semiconductor ...
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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 ...
Страница 506: ...Voltage Regulator S12VREGL3V3V1 S12XS Family Reference Manual Rev 1 13 506 Freescale Semiconductor ...
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