2 introduction, Introduction – Freescale Semiconductor MC68HC08KH12 User Manual

Page 62

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Advance Information

MC68HC(7)08KH12

Rev. 1.1

62

Freescale Semiconductor

7.7

Low-Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

7.7.1

Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

7.7.2

Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

7.8

SIM Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

7.8.1

Break Status Register (BSR). . . . . . . . . . . . . . . . . . . . . . . . 83

7.8.2

Reset Status Register (RSR) . . . . . . . . . . . . . . . . . . . . . . . 84

7.8.3

Break Flag Control Register (BFCR). . . . . . . . . . . . . . . . . . 85

7.2 Introduction

This section describes the system integration module (SIM), which
supports up to 24 external and/or internal interrupts. Together with the
CPU, the SIM controls all MCU activities. A block diagram of the SIM is
shown in

Figure 7-1

.

Figure 7-2

is a summary of the SIM I/O registers.

The SIM is a system state controller that coordinates CPU and exception
timing. The SIM is responsible for:

Bus clock generation and control for CPU and peripherals

top/wait/reset/break entry and recovery

Internal clock control

Master reset control, including power-on reset (POR) and COP
timeout

Interrupt control:

Acknowledge timing

Arbitration control timing

Vector address generation

CPU enable/disable timing

Modular architecture expandable to 128 interrupt sources

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