
Clock Functions
Clock Function Registers
MC68HC912D60A — Rev 3.0
Technical Data
MOTOROLA
Clock Functions
169
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 XCLK.
RTIF — Real Time Interrupt Flag
This bit is cleared automatically by a write to this register with this bit
set.
0 = Time-out has not yet occurred.
1 = Set when the time-out period is met.
Table 11-4. Real Time Interrupt Rates
RTR2 RTR1 RTR0 Divide X By:
Time-Out Period
X = 125 KHz
Time-Out Period
X = 500 KHz
Time-Out Period
X = 2.0 MHz
Time-Out Period
X = 8.0 MHz
0
OFF
00
1
213
65.536 ms
16.384 ms
4.096 ms
1.024 ms
01
0
214
131.72 ms
32.768 ms
8.196 ms
2.048 ms
01
1
215
263.44 ms
65.536 ms
16.384 ms
4.096 ms
10
0
216
526.88 ms
131.72 ms
32.768 ms
8.196 ms
10
1
217
1.05 s
263.44 ms
65.536 ms
16.384 ms
11
0
218
2.11 s
526.88 ms
131.72 ms
32.768 ms
11
1
219
4.22 s
1.05 s
263.44 ms
65.536 ms
Bit 7
654321
Bit 0
RTIF
0000000
RESET:
00000000
RTIFLG — Real Time Interrupt Flag Register
$0015