Z8F1680SH020SG Datasheet, PDF (60/412 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F1680 Series
Product Specification
35
V
V_CC(min)
V_POR
V_TH
V_CC
POR
POR
No POR
POR
Reset
t_{(POR_DELAY)}
t_{(POR_DELAY)}
Figure 7. Power-On Reset Timing
5.2.2. Voltage Brown-Out Reset
The F1680 Series MCU provides a VBO Reset feature for low-voltage protection. The
VBO circuit has a preset threshold voltage (V_VBO) with a hysteresis of V_HYS. The VBO
circuit will monitor the power supply voltage if the VBO is enabled. When VBO Reset
circuit detects the power supply voltage falls below the threshold voltage V_VBO, the VBO
resets the device by pulling the POR Reset from 1 to 0. The VBO will hold the POR Reset
until the power supply voltage goes above the V_VBO+(V_VBO+V_HYS) and then the VBO
Reset is released. The device progresses through a full System Reset sequence, just like
power-on case. Following this System Reset sequence, the POR/VBO status bit in the
Reset Status (RSTSTAT) register is set to 1. Figure 8 on page 36 displays VBO Reset
operation.
For VBO threshold voltages (V_VBO) and VBO hysteresis (V_HYS), see the Electrical Char-
acteristics chapter on page 349.
The VBO circuit is either enabled or disabled during STOP Mode. VBO circuit operation
is controlled by both the VBO_AO Flash option bit and the Power Control Register bit4.
For more details, see the Flash Option Bits chapter on page 276 and the Power Control
Register Definitions section on page 44.
PS025015-1212
P R E L I M I N A R Y Reset, Stop Mode Recovery and Low-Voltage