MC68HC908MR8 Datasheet, PDF (99/372 Pages) Motorola, Inc – Microcontrollers

System Integration Module (SIM)
SIM Counter
7.5 SIM Counter
The SIM counter is used by the POR module to allow the oscillator time
to stabilize before enabling the internal bus (IBUS) clocks. The SIM
counter also serves as a prescaler for the COP module. The SIM counter
overflow supplies the clock for the COP module. The SIM counter is 13
bits long and is clocked by the falling edge of CGMXCLK.
7.5.1 SIM Counter During Power-On Reset
The POR detects power applied to the MCU. At power-on, the POR
circuit asserts the signal PORRST. Once the SIM is initialized, it enables
the clock generation module (CGM) to drive the bus clock state machine.
7.5.2 SIM Counter and Reset States
External reset has no effect on the SIM counter. The SIM counter is
free-running after all reset states. See 7.4.2 Active Resets from
Internal Sources for counter control and internal reset recovery
sequences.
7.6 Exception Control
Normal, sequential program execution can be changed in three different
ways:
1. Interrupts:
a. Maskable hardware CPU interrupts
b. Non-maskable software interrupt instruction (SWI)
2. Reset
3. Break interrupts
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor
System Integration Module (SIM)
Technical Data
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