MC68HC05P18 Datasheet, PDF (49/144 Pages) Freescale Semiconductor, Inc – Advance Information

Freescale Semiconductor, Inc.
Advance Information — MC68HC05P18/MC68HC805P18
Section 5. Resets
5.1 Contents
5.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
5.3 External Reset (RESET). . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
5.4 Internal Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
5.4.1 Power-On Reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
5.4.2 Computer Operating Properly (COP) Reset . . . . . . . . . . . . .51
5.4.3 Low-Voltage Reset (LVR). . . . . . . . . . . . . . . . . . . . . . . . . . .51
5.2 Introduction
The MCU can be reset from four sources: one external input and three
internal reset conditions. The RESET pin is an input with a Schmitt
trigger as shown in Figure 5-1. The CPU and all peripheral modules will
be reset by the RST signal which is the logical OR of internal reset
functions and is clocked by PH2.
5.3 External Reset (RESET)
The RESET input is the only external reset and is connected to an
internal Schmitt trigger. The external reset occurs whenever the RESET
input is driven below the lower threshold and remains in reset until the
RESET pin rises above the upper threshold. The upper and lower
thresholds are given in Section 13. Electrical Specifications.
MC68HC(8)05P18 — Rev. 2.0
MOTOROLA
Resets
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Advance Information
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