mc9s08qg8 Freescale Semiconductor, Inc, mc9s08qg8 Datasheet - Page 71

• Manufacturer Part Number: mc9s08qg8
• Description: Hcs08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

5.8.7
This high page register contains status and control bits for the RTI.
1
2
3
Freescale Semiconductor
RTICLKS
Reset:
Values are shown in this column based on t
tolerance of this value.
The initial RTI timeout period will be up to one 1-kHz clock period less than the time specified.
t
RTIACK
ext
RTIS2:RTIS1:RTIS0
Field
RTIE
RTIS
RTIF
2:0
is the period of the external crystal frequency.
7
6
5
4
W
R
0:0:0
0:0:1
0:1:0
0:1:1
1:0:0
1:0:1
1:1:0
1:1:1
System Real-Time Interrupt Status and Control Register (SRTISC)
RTIF
Real-Time Interrupt Flag — This read-only status bit indicates the periodic wakeup timer has timed out.
0 Periodic wakeup timer not timed out.
1 Periodic wakeup timer timed out.
Real-Time Interrupt Acknowledge — This write-only bit is used to acknowledge real-time interrupt request
(write 1 to clear RTIF). Writing 0 has no meaning or effect. Reads always return 0.
Real-Time Interrupt Clock Select — This read/write bit selects the clock source for the real-time interrupt.
0 Real-time interrupt request clock source is internal 1-kHz oscillator.
1 Real-time interrupt request clock source is external clock.
Real-Time Interrupt Enable — This read-write bit enables real-time interrupts.
0 Real-time interrupts disabled.
1 Real-time interrupts enabled.
Real-Time Interrupt Delay Selects — These read/write bits select the period for the RTI. See
0
7
= Unimplemented or Reserved
Figure 5-9. System RTI Status and Control Register (SRTISC)
RTIACK
0
0
6
Using Internal 1-kHz Clock Source
Table 5-10. SRTISC Register Field Descriptions
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
Table 5-11. Real-Time Interrupt Period
RTICLKS
0
5
RTI
Disable RTI
128 ms
256 ms
512 ms
1.024 s
32 ms
64 ms
= 1 ms. See t
8 ms
RTIE
0
4
RTI
Description
in the appendix
1 2
Chapter 5 Resets, Interrupts, and General System Control
3
0
0
Section A.8.1, “Control
Using External Clock Source
0
2
Period = t
Disable RTI
t
t
t
t
t
t
ext
ext
t
ext
ext
ext
ext
ext
x 16384
x 32768
x 1024
x 2048
x 4096
x 8192
x 256
RTIS
0
1
ext
Timing,” for the
3
Table
5-11.
0
0
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