MC9S08GB60 Datasheet, PDF (73/290 Pages) Motorola, Inc – Microcontrollers

Reset, Interrupt, and System Control Registers and Control Bits
ID[11:0] — Part Identification Number
Each derivative in the HCS08 Family has a unique identification number. The MC9S08GB/GT is hard
coded to the value $002.
5.8.6 System Real-Time Interrupt Status and Control Register (SRTISC)
This register contains one read-only status flag, one write-only acknowledge bit, three read/write delay
selects, and three unimplemented bits, which always read 0.
Bit 7
6
5
4
3
2
1
Read: RTIF
Write:
0
RTICLKS RTIE
RTIACK
0
RTIS2 RTIS1
Reset: 0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 5-7. System RTI Status and Control Register (SRTISC)
Bit 0
RTIS0
0
RTIF — Real-Time Interrupt Flag
This read-only status bit indicates the periodic wakeup timer has timed out.
1 = Periodic wakeup timer timed out.
0 = Periodic wakeup timer not timed out.
RTIACK — 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.
RTICLKS — Real-Time Interrupt Clock Select
This read/write bit selects the clock source for the real-time interrupt.
1 = Real-time interrupt request clock source is external clock.
0 = Real-time interrupt request clock source is internal oscillator.
RTIE — Real-Time Interrupt Enable
This read-write bit enables real-time interrupts.
1 = Real-time interrupts enabled.
0 = Real-time interrupts disabled.
RTIS2:RTIS1:RTIS0 — Real-Time Interrupt Period Selects
These read/write bits select the wakeup period for the RTI. The clock source for the real-time interrupt
is its own clock source, which oscillates with a period of approximately 1/f_ext, and it is independent of
other MCU clock sources. Using an external clock source, the delays will be crystal frequency divided
by value in RTIS2:RTIS1:RTIS0.
MC9S08GB/GT Data Sheet, Rev. 2.3
Freescale Semiconductor
73