Datasheet

ManualsBrandsNXP SEMICONDUCTORS ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller QFP 80 (14x14) 16-Bit 8 MHz I/O number 63

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msCAN12 Controller

M68HC12B Family Data Sheet, Rev. 9.1

266 Freescale Semiconductor

The bit time is determined by the oscillator frequency, the baud rate prescaler, and the number of time

quanta (Tq) clock cycles per bit (as shown in Table 16-8).

NOTE

The CBTR1 register can be written only if the SFTRES bit in CMCR0 is set.

16.12.5 msCAN12 Receiver Flag Register

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 longer.

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.

WUPIF — Wakeup Interrupt Flag

If the msCAN12 detects bus activity while in sleep mode, it sets the WUPIF flag. If not masked, a

wakeup interrupt is pending while this flag is set.

0 = No wakeup activity has been observed while in sleep mode.

1 = msCAN12 has detected activity on the bus and requested wakeup.

RWRNIF — Receiver Warning Interrupt Flag

This flag is set when the msCAN12 goes into warning status due to the receive error counter (REC)

exceeding 96 and neither one of the error interrupt flags nor the bus-off interrupt flag is set

(1)

. If not

masked, an error interrupt is pending while this flag is set.

0 = No receiver warning status has been reached.

1 = msCAN12 went into receiver warning status.

TWRNIF — Transmitter Warning Interrupt Flag

This bit will be set when the msCAN12 goes into warning status due to the transmit error counter (TEC)

exceeding 96 and neither one of the error interrupt flags nor the bus-off interrupt flag is set

(2)

. If not

masked, an error interrupt is pending while this flag is set.

0 = No transmitter warning status has been reached.

1 = msCAN12 went into transmitter warning status.

Address: $0104

Bit 7654321Bit 0

Read:

WUPIF RWRNIF TWRNIF RERRIF TERRIF BOFFIF OVRIF RXF

Write:

Reset:00000000

Figure 16-20. msCAN12 Receiver Flag Register (CRFLG)

1. Condition to set the flag: RWRNIF = (96 ≤ REC ≤ 127) & RERRIF & TERRIF & BOFFIF

2. Condition to set the flag: TWRNIF = (96 ≤ TEC ≤ 127) & RERRIF & TERRIF & BOFFIF

BitTime

Presc valueÞ

CGMCANCLK

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number• of TimeQuantaÞÞ=