
Timing System
Real-Time Interrupt (RTI)
MC68HC11E Family
—
Rev. 4
Technical Data
MOTOROLA
Timing System
201
9.6.2 Timer Interrupt Flag Register 2
Bits of this register indicate the occurrence of timer system events.
Coupled with the four high-order bits of TMSK2, the bits of TFLG2 allow
the timer subsystem to operate in either a polled or interrupt driven
system. Each bit of TFLG2 corresponds to a bit in TMSK2 in the same
position.
Clear flags by writing a 1 to the corresponding bit position(s).
TOF
—
Timer Overflow Interrupt Flag
Set when TCNT changes from $FFFF to $0000
RTIF
—
Real-Time Interrupt Flag
The RTIF status bit is automatically set to 1 at the end of every RTI
period. To clear RTIF, write a byte to TFLG2 with bit 6 set.
PAOVF
—
Pulse Accumulator Overflow Interrupt Flag
Refer to
9.8 Pulse Accumulator
.
PAIF
—
Pulse Accumulator Input Edge Interrupt Flag
Refer to
9.8 Pulse Accumulator
.
Bits [3:0]
—
Unimplemented
Always read 0
Address:
$1025
Bit 7
6
5
4
3
2
1
Bit 0
Read:
TOF
RTIF
PAOVF
PAIF
Write:
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 9-22. Timer Interrupt Flag 2 Register (TFLG2)