Z8F6421PM020SC Datasheet, PDF (69/299 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers Z8 Encore-R 64K Series

Z8 Encore!^® 64K Series
Product Specification
49
Low-Power Modes
Overview
The 64K Series products contain power-saving features. The highest level of power reduc-
tion is provided by STOP mode. The next level of power reduction is provided by the
HALT mode.
STOP Mode
Execution of the eZ8 CPU’s STOP instruction places the device into STOP mode. In
STOP mode, the operating characteristics are:
• Primary crystal oscillator is stopped; the XIN pin is driven High and the XOUT pin is
driven Low.
• System clock is stopped
• eZ8 CPU is stopped
• Program counter (PC) stops incrementing
• The Watch-Dog Timer and its internal RC oscillator continue to operate, if enabled for
operation during STOP mode.
• The Voltage Brown-Out protection circuit continues to operate, if enabled for
operation in STOP mode using the associated Option Bit.
• All other on-chip peripherals are idle.
To minimize current in STOP mode, all GPIO pins that are configured as digital inputs
must be driven to one of the supply rails (V_CC or GND), the Voltage Brown-Out protection
must be disabled, and the Watch-Dog Timer must be disabled. The devices can be brought
out of STOP mode using STOP Mode Recovery. For more information on STOP Mode
Recovery refer to the Reset and STOP Mode Recovery chapter beginning on page 43.
Caution:
STOP Mode must not be used when driving the 64K Series devices with
an external clock driver source.
PS019915-1005
Low-Power Modes