mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 187

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

4.4.6
The RTI can be used to generate a hardware interrupt at a fixed periodic rate. If enabled (by setting
RTIE=1), this interrupt will occur at the rate selected by the RTICTL register. The RTI runs with a gated
OSCCLK (see
time-out period starts immediately.
A write to the RTICTL register restarts the RTI time-out period.
If the PRE bit is set, the RTI will continue to run in pseudo-stop mode.
4.4.7
4.4.7.1
The CRGV4 block behaves as described within this specification in all normal modes.
4.4.7.2
The VCO has a minimum operating frequency, f
to a failure or due to long crystal start-up time, the bus clock and the core clock are derived from the VCO
Freescale Semiconductor
Real-Time Interrupt (RTI)
Modes of Operation
Normal Mode
Self-Clock Mode
Figure
gating condition
OSCCLK
4-22). At the end of the RTI time-out period the RTIF flag is set to 1 and a new RTI
= Clock Gate
STOP(PSTP,PRE),
WAIT(RTIWAI),
RTI enable
Figure 4-22. Clock Chain for RTI
MC9S12E256 Data Sheet, Rev. 1.08
2
2
2
2
2
2
SCM
1024
.
. If the external clock frequency is not available due
RTR[6:4]
0:1:0
0:0:1
0:1:1
1:0:0
1:0:1
1:1:0
1:1:1
0:0:0
COUNTER (RTR[3:0])
4-BIT MODULUS
Chapter 4 Clocks and Reset Generator (CRGV4)
RTI TIMEOUT
187