mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 97

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

1
Freescale Semiconductor
RTICLKS
RTIS[2:0]
Normal values shown in this column are based on f
Reset
RTIACK
RTIS2:RTIS1:RTIS0
Field
RTIE
RTIF
2–0
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
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 logic 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 wakeup delay for the RTI. The clock
source for the real-time interrupt is a self-clocked source which oscillates at about 1 kHz, is independent of other
MCU clock sources. Using external clock source the delays will be crystal frequency divided by value in
RTIS2:RTIS1:RTIS0. See
0
7
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Figure 5-7. System RTI Status and Control Register (SRTISC)
RTIACK
0
0
6
Table 5-10. SRTISC Register Field Descriptions
1 kHz LPO Clock Source Delay
Disable periodic wakeup timer
Table 5-11. Real-Time Interrupt Frequency
Table
RTICLKS
0
5
5-11.
128 ms
256 ms
512 ms
1.024 s
32 ms
64 ms
8 ms
RTI
= 1 kHz.
RTIE
0
4
Description
1
3
0
0
Resets, Interrupts, and General System Control
Using External Clock Source Delay
Disable periodic wakeup timer
RTIS2
0
2
(Crystal Frequency)
divide by 16384
divide by 32768
divide by 2048
divide by 4096
divide by 8192
divide by 1024
divide by 256
RTIS1
0
1
RTIS0
0
0
5-15