Technical data

MOTOROLA MC68HC912B32
58 MC68HC912B32TS/D
10.5 Clock Function Registers
All register addresses shown reflect the reset state. Registers may be mapped to any 2-Kbyte space.
RTIE — Real-Time Interrupt Enable
Read and write anytime.
0 = Interrupt requests from RTI are disabled.
1 = Interrupt will be requested whenever RTIF is set.
RSWAI — RTI and COP Stop While in Wait
Write once in normal modes, anytime in special modes. Read anytime.
0 = Allows the RTI and COP to continue running in wait.
1 = Disables both the RTI and COP whenever the part goes into wait.
RSBCK — RTI and COP Stop While in Background Debug Mode
Write once in normal modes, anytime in special modes. Read anytime.
0 = Allows the RTI and COP to continue running while in background mode.
1 = Disables both the RTI and COP whenever the part is in background mode. This is useful for
emulation.
RTBYP — Real-Time Interrupt Divider Chain Bypass
Write not allowed in normal modes, anytime in special modes. Read anytime.
0 = Divider chain functions normally.
1 = Divider chain is bypassed, allows faster testing (the divider chain is normally P divided by 2
13
,
when bypassed becomes P divided by 4).
RTR2, RTR1, RTR0 — Real-Time Interrupt Rate Select
Read and write anytime.
Rate select for real-time interrupt. The clock used for this module is the E clock.
Table 19 Clock Monitor Time-Outs
Supply Range
5V +/− 10% 2-20 µS
3V +/− 10% 5-100 µS
RTICTL — Real-Time Interrupt Control Register $0014
Bit 7 6 5 4 3 2 1 Bit 0
RTIE RSWAI RSBCK 0 RTBYP RTR2 RTR1 RTR0
RESET: 0 0 0 0 0 0 0 0
Table 20 Real-Time Interrupt Rates
RTR2 RTR1 RTR0 Divide E By:
Time-Out Period
E = 4.0 MHz
Time-Out Period
E = 8.0 MHz
0 0 0 OFF OFF OFF
001
2
13
2.048 ms 1.024 ms
010
2
14
4.096 ms 2.048 ms
011
2
15
8.196 ms 4.096 ms
100
2
16
16.384 ms 8.196 ms
101
2
17
32.768 ms 16.384 ms
110
2
18
65.536 ms 32.768 ms
111
2
19
131.72 ms 65.536 ms