MC68HCP11 Datasheet, PDF (32/45 Pages) Motorola, Inc – 8-Bit Microcontroller

8 Main Timer
The main timer is based on a free-running 16-bit counter with a four-stage programmable prescaler. A
timer overflow function allows software to extend the system's timing capability beyond the counter's
16-bit range.
The timer has three channels of input capture and five channels of output compare.
Refer to the following table for a summary of crystal-related frequencies and periods.
Control
Bits
PR[1:0]
00
1 count —
overflow —
01
1 count —
overflow —
10
1 count —
overflow —
11
1 count —
overflow —
RTR[1:0]
00
01
10
11
Table 6 Timer Summary
4.0 MHz
1.0 MHz
1000 ns
XTAL Frequencies
8.0 MHz
12.0 MHz
2.0 MHz
3.0 MHz
500 ns
333 ns
Main Timer Count Rates
1.0 µs
65.536 ms
500 ns
32.768 ms
333 ns
21.845 ms
4.0 µs
262.14 ms
2.0 µs
131.07 ms
1.333 µs
87.381 ms
8.0 µs
524.29 ms
4.0 µs
262.14 ms
2.667 µs
174.76 ms
16.0 µs
1.049 s
8.192 ms
16.384 ms
32.768 ms
65.536 ms
8.0 µs
524.29 ms
5.333 µs
349.52 ms
Periodic (RTI) Interrupt Rates
4.096 ms
8.192 ms
16.384 ms
32.768 ms
2.731 ms
5.461 ms
10.923 ms
21.845 ms
Other Rates
(E)
(1/E)
(E/1)
(E/2¹⁶)
(E/4)
(E/2¹⁸)
(E/8)
(E/2¹⁹)
(E/16)
(E/2²⁰)
(E/2¹³)
(E/2¹⁴)
(E/2¹⁵)
(E/2¹⁶)
MOTOROLA
32
MC68HC11A8
MC68HC11A8TS/D