MC68HC908QC16_07 Datasheet, PDF (93/274 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 9
Low-Voltage Inhibit (LVI)
9.1 Introduction
The low-voltage inhibit (LVI) module is provided as a system protection mechanism to prevent the MCU
from operating below a certain operating supply voltage level. The module has several configuration
options to allow functionality to be tailored to different system level demands.
The configuration registers (see Chapter 4 Configuration Registers (CONFIG1 and CONFIG2)) contain
control bits for this module.
9.2 Features
Features of the LVI module include:
• Programmable LVI reset
• Selectable LVI trip voltage
• Programmable stop mode operation
9.3 Functional Description
Figure 9-1 shows the structure of the LVI module. LVISTOP, LVIPWRD, LVITRIP, and LVIRSTD are user
selectable options found in the configuration register.
V_DD
STOP INSTRUCTION
LVISTOP
FROM CONFIGURATION REGISTER
FROM CONFIGURATION REGISTER
LVIPWRD
LVIRSTD
FROM CONFIGURATION REGISTER
LOW V_DD
DETECTOR
0 IF V_DD > V_TRIPR
1 IF V_DD ≤ V_TRIPF
LVITRIP
FROM CONFIGURATION REGISTER
LVIOUT
Figure 9-1. LVI Module Block Diagram
LVI RESET
MC68HC908QC16 • MC68HC908QC8 • MC68HC908QC4 Data Sheet, Rev. 3
Freescale Semiconductor
93