mc68hc11f1cpu3 Freescale Semiconductor, Inc, mc68hc11f1cpu3 Datasheet - Page 119

• Manufacturer Part Number: mc68hc11f1cpu3
• Description: Mc68hc11f1 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

9.4.1 Timer Interrupt Mask Register 2
TMSK2 — Timer Interrupt Mask Register 2
TOI — Timer Overflow Interrupt Enable
RTII — Real-Time Interrupt Enable
PAOVI — Pulse Accumulator Overflow Interrupt Enable
PAII — Pulse Accumulator Input Edge
PR[1:0] — Timer Prescaler Select
TECHNICAL DATA
RESET:
The clock source for the RTI function is a free-running clock that cannot be stopped or
interrupted except by reset. This clock causes the time between successive RTI time-
outs to be a constant that is independent of the software latencies associated with flag
clearing and service. For this reason, an RTI period starts from the previous time-out,
not from when RTIF is cleared.
Every time-out causes the RTIF bit in TFLG2 to be set, and if RTII is set, an interrupt
request is generated. After reset, one entire RTI period elapses before the RTIF flag
is set for the first time. Refer to the TMSK2, TFLG2, and PACTL registers.
This register contains the real-time interrupt enable bits.
Refer to 9.6 Pulse Accumulator.
Refer to 9.6 Pulse Accumulator.
Refer to Table 9-4.
RTR[1:0]
0 = TOF interrupts disabled
1 = Interrupt requested when TOF is set to one
0 = RTIF interrupts disabled
1 = Interrupt requested when RTIF set to one
0 0
0 1
1 0
1 1
Bit 7
TOI
0
Bits in TMSK2 correspond bit for bit with flag bits in TFLG2. Ones in
TMSK2 enable the corresponding interrupt sources.
E = 1 MHz
16.384 ms
32.768 ms
65.536 ms
8.192 ms
RTII
6
0
Freescale Semiconductor, Inc.
For More Information On This Product,
PAOVI
Table 9-4 RTI Rate Selection
5
0
Go to: www.freescale.com
E = 2 MHz
16.384 ms
32.768 ms
4.096 ms
8.192 ms
TIMING SYSTEM
PAII
4
0
NOTE
E = 3 MHz
10.923 ms
21.845 ms
2.731 ms
5.461 ms
—
0
3
—
2
0
E = 4 MHz
16.384 ms
2.048 ms
4.096 ms
8.192 ms
PR1
1
0
Bit 0
PR0
E = X MHz
0
(2
(2
(2
(2
13
14
15
16
/E)
/E)
/E)
/E)
$1024
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