MC908QL4 FREESCALE [Freescale Semiconductor, Inc], MC908QL4 Datasheet - Page 117

• Manufacturer Part Number: MC908QL4
• Description: M68HC08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Chapter 13
System Integration Module (SIM)
13.1 Introduction
This section describes the system integration module (SIM), which supports up to 24 external and/or
internal interrupts. Together with the central processor unit (CPU), the SIM controls all microcontroller unit
(MCU) activities. A block diagram of the SIM is shown in
that coordinates CPU and exception timing.
The SIM is responsible for:
Freescale Semiconductor
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Bus clock generation and control for CPU and peripherals
–
–
Master reset control, including power-on reset (POR) and computer operating properly (COP)
timeout
Interrupt control:
–
–
–
CPU enable/disable timing
Stop/wait/reset/break entry and recovery
Internal clock control
Acknowledge timing
Arbitration control timing
Vector address generation
Signal Name
Address bus
BUSCLKX4
BUSCLKX2
PORRST
Data bus
IRST
R/W
Table 13-1. Signal Name Conventions
Buffered clock from the internal, RC or XTAL oscillator circuit.
The BUSCLKX4 frequency divided by two. This signal is again
divided by two in the SIM to generate the internal bus clocks
(bus clock = BUSCLKX4 ÷ 4).
Internal address bus
Internal data bus
Signal from the power-on reset module to the SIM
Internal reset signal
Read/write signal
MC68HC908QL4 Data Sheet, Rev. 7
Figure
Description
13-1. The SIM is a system state controller
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