MC68HC11F1 Datasheet, PDF (63/68 Pages) Motorola, Inc – Technical Summary 8-Bit Microcontroller

RTIF — Real-Time Interrupt Flag
Set periodically at a rate based on bits RTR[1:0] in the PACTL register.
Bits [5:4] — See 13.2 Pulse Accumulator Registers, page 65.
Bits [3:0] — Not implemented. Reads always return zero and writes have no effect.
PACTL — Pulse Accumulator Control
Bit 7
6
5
4
3
2
1
0
PAEN PAMOD PEDGE
0
I4/O5
RTR1
RESET:
0
0
0
0
0
0
0
Bit 0
RTR0
0
$x026
Bit 7 — Not implemented. Reads always return zero and writes have no effect.
Bits [6:4] — See 13.2 Pulse Accumulator Registers, page 65.
Bit 3 — Not implemented. Reads always return zero and writes have no effect.
I4/O5 — Configure TI4/O5 Register for IC or OC
0 = OC5 function enabled
1 = IC4 function enabled
RTR[1:0] — RTI Interrupt Rate Selects
These two bits select one of four rates for the real-time interrupt circuit, as shown in Table 32.
Table 32 Real-Time Interrupt Periods
E-Clock
Frequency
1 MHz
2 MHz
3 MHz
4 MHz
5 MHz
6 MHz
Any E
RTR [1:0] = %00
8.192 ms
4.906 ms
2.731 ms
2.048 ms
1.638 ms
1.366 ms
2¹³/E
RTR [1:0] = 01
16.384 ms
8.192 ms
5.461 ms
4.096 ms
3.277 ms
2.731 ms
2¹⁴/E
RTR [1:0] = 10
32.768 ms
16.384 ms
10.923 ms
8.192 ms
6.554 ms
5.461 ms
2¹⁵/E
RTR [1:0] = 11
65.536 ms
32.768 ms
21.845 ms
16.384 ms
13.107 ms
10.923 ms
2¹⁶/E
MC68HC11F1/FC0
MC68HC11FTS/D
MOTOROLA
63