MC908AS60ACFU Datasheet, PDF (291/414 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

Programmer’s Model of Control Registers
23.13.5 MSCAN08 Receiver Flag Register (CRFLG)
All bits of this register are read and clear only. A flag can be cleared by writing a 1 to the corresponding
bit position. A flag can be cleared only when the condition which caused the setting is valid no more.
Writing a 0 has no effect on the flag setting. Every flag has an associated interrupt enable flag in the
CRIER register. A hard or soft reset will clear the register.
Address: $0504
Bit 7
6
5
4
3
2
1
Bit 0
Read:
WUPIF RWRNIF TWRNIF RERRIF TERRIF BOFFIF OVRIF
RXF
Write:
Reset: 0
0
0
0
0
0
0
0
Figure 23-19. Receiver Flag Register (CRFLG)
WUPIF — Wakeup Interrupt Flag
If the MSCAN08 detects bus activity while in Sleep mode, it sets the WUPIF flag. If not masked, a
wake-up interrupt is pending while this flag is set.
1 = MSCAN08 has detected activity on the bus and requested wake-up.
0 = No wake-up interrupt has occurred.
RWRNIF — Receiver Warning Interrupt Flag
This flag is set when the MSCAN08 goes into warning status due to the receive error counter (REC)
exceeding 96 and neither one of the Error Interrupt flags or the Bus-off Interrupt flag is set⁽¹⁾. If not
masked, an error interrupt is pending while this flag is set.
1 = MSCAN08 has gone into receiver warning status.
0 = No receiver warning status has been reached.
TWRNIF — Transmitter Warning Interrupt Flag
This flag is set when the MSCAN08 goes into warning status due to the transmit error counter (TEC)
exceeding 96 and neither one of the error interrupt flags or the bus-off interrupt flag is set⁽²⁾. If not
masked, an error interrupt is pending while this flag is set.
1 = MSCAN08 has gone into transmitter warning status.
0 = No transmitter warning status has been reached.
RERRIF — Receiver Error Passive Interrupt Flag
This flag is set when the MSCAN08 goes into error passive status due to the receive error counter
exceeding 127 and the bus-off interrupt flag is not set⁽³⁾. If not masked, an Error interrupt is pending
while this flag is set.
1 = MSCAN08 has gone into receiver error passive status.
0 = No receiver error passive status has been reached.
1. Condition to set the flag: RWRNIF = (96 ≤ REC) & RERRIF & TERRIF & BOFFIF
2. Condition to set the flag: TWRNIF = (96 ≤ TEC) & RERRIF & TERRIF & BOFFIF
3. Condition to set the flag: RERRIF = (127 ≤ REC ≤ 255) & BOFFIF
MC68HC908AZ60A • MC68HC908AS60A • MC68HC908AS60E Data Sheet, Rev. 6
Freescale Semiconductor
291