MC908QY8CDWE Datasheet, PDF (91/232 Pages) Freescale Semiconductor, Inc – Addendum to MC68HC908QB8, rev. 3

Chapter 10
Low-Voltage Inhibit (LVI)
10.1 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 5 Configuration Register (CONFIG)) contain control bits for this
module.
10.2 Features
Features of the LVI module include:
• Programmable LVI reset
• Selectable LVI trip voltage
• Programmable stop mode operation
10.3 Functional Description
Figure 10-1 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
LVIOUT
FROM CONFIGURATION REGISTER
Figure 10-1. LVI Module Block Diagram
LVI RESET
MC68HC908QB8 Data Sheet, Rev. 3
Freescale Semiconductor
89