Z8F082ASH020SC Datasheet, PDF (40/244 Pages) Zilog, Inc. – Z8 Encore XP-R F08xA Series with eXtended Peripherals

Z8 Encore! XP^® F08xA Series
Product Specification
22
V_POR
V_VBO
VCC = 0.0V
VCC = 3.3V
Program
Execution
Internal Precision
Oscillator
Crystal
Oscillator
Internal RESET
signal
Note: Not to Scale
Oscillator
Start-up
POR
counter delay
optional XTAL
counter delay
Figure 4.Power-On Reset Operation
Voltage Brown-Out Reset
The devices in the Z8 Encore! XP^® F08xA Series provide low Voltage Brown-Out (VBO)
protection. The VBO circuit senses when the supply voltage drops to an unsafe level
(below the VBO threshold voltage) and forces the device into the Reset state. While the
supply voltage remains below the Power-On Reset voltage threshold (V_POR), the VBO
block holds the device in the Reset.
After the supply voltage again exceeds the Power-On Reset voltage threshold, the device
progresses through a full System Reset sequence, as described in the Power-On Reset sec-
tion. Following Power-On Reset, the POR status bit in the Reset Status (RSTSTAT) regis-
ter is set to 1. Figure 5 illustrates Voltage Brown-Out operation. Refer to the chapter
“Electrical Characteristics” on page 191 for the VBO and POR threshold voltages (V_VBO
and V_POR).
The Voltage Brown-Out circuit can be either enabled or disabled during STOP mode.
Operation during STOP mode is set by the VBO_AO Flash Option Bit. Refer to the Flash
Option Bits chapter for information about configuring VBO_AO.
PS024705-0405
PRELIMINARY
Reset and STOP Mode Recovery