PR[1:0]
0 0
Prescaler
1
4
0 1
1 0
8
1 1
16
TFLG2 — Timer Interrupt Flag 2
$1025
Bit 7
TOF
0
6
RTIF
0
5
PAOVF
0
4
3
0
0
2
0
0
1
0
0
Bit 0
PAIF
0
0
RESET:
0
Clear flags by writing a one to the corresponding bit position(s).
TOF — Timer Overflow Flag
Set when TCNT changes from $FFFF to $0000.
RTIF — Real-Time (Periodic) Interrupt Flag
Set periodically. Refer to RTR[1:0] bits in PACTL register.
PAOVF — Pulse Accumulator Overflow Interrupt Flag
Refer to 9 Pulse Accumulator.
PAIF — Pulse Accumulator Input Edge Interrupt Flag
Refer to 9 Pulse Accumulator.
PACTL — Pulse Accumulator Control
$1026
Bit 7
DDRA7
0
6
PAEN
0
5
4
3
0
0
2
0
0
1
RTR1
0
Bit 0
RTR0
0
PAMOD PEDGE
RESET:
0
0
DDRA7 — Data Direction for Port A Bit 7
Refer to 5 Parallel Input/Output.
PAEN — Pulse Accumulator Enable
Refer to 9 Pulse Accumulator.
PAMOD — Pulse Accumulator Mode Select
Refer to 9 Pulse Accumulator.
PEDGE — Pulse Accumulator Edge Select
Refer to 9 Pulse Accumulator.
RTR [1:0] — Real-Time Interrupt (RTI) Rate
Table 8 Real-Time Interrupt Rates
RTR[1:0]
Divide E By
XTAL = 4.0 MHz
XTAL = 8.0 MHz
XTAL = 12.0 MHz
13
14
15
16
0 0
8.19 ms
4.096 ms
8.192 ms
16.384 ms
32.768 ms
2.0 MHz
2.731 ms
2
2
2
2
0 1
1 0
1 1
16.38 ms
32.77 ms
65.54 ms
1.0 MHz
5.461 ms
10.923 ms
21.845 ms
3.0 MHz
E =
MC68HC11A8
MC68HC11A8TS/D
MOTOROLA
37
MOTOROLA [ MOTOROLA ]
