68HC705V12 Datasheet, PDF (67/248 Pages) Motorola, Inc – The Motorola microcontroller

Advance Information — MC68HC705V12
Section 5. Resets
5.1 Contents
5.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
5.3 External Reset (RESET). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
5.4 Internal Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
5.4.1 Power-On Reset (POR). . . . . . . . . . . . . . . . . . . . . . . . . . . .69
5.4.2 Computer Operating Properly Reset (COPR) . . . . . . . . . . .71
5.4.2.1 Resetting the COP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
5.4.2.2 COP during Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . .71
5.4.2.3 COP during Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . .71
5.4.2.4 COP Watchdog Timer Considerations . . . . . . . . . . . . . . .72
5.4.2.5 COP Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
5.4.3 Illegal Address Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
5.4.4 Disabled STOP Instruction Reset . . . . . . . . . . . . . . . . . . . .73
5.4.5 Low-Voltage Reset (LVR) . . . . . . . . . . . . . . . . . . . . . . . . . .73
5.4.6 LVR Operation in Stop and Wait Modes . . . . . . . . . . . . . . .74
5.2 Introduction
The MCU can be reset from six sources:
• One external input
• Five internal restart conditions
The RESET pin is an input with a Schmitt trigger as shown in Figure 5-1.
All the internal peripheral modules will be reset by the internal reset
signal (RST). Refer to Figure 5-2 for reset timing details.
MC68HC705V12 — Rev. 3.0
MOTOROLA
Resets
Advance Information
67