z8f0822 ZiLOG Semiconductor, z8f0822 Datasheet - Page 54

• Manufacturer Part Number: z8f0822
• Description: High Performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS022517-0508
Internal RESET
WDT Clock
Not to Scale
V
Oscillator
Primary
CC
signal
Power-On Reset
Voltage Brownout Reset
= 0.0 V
V
V
POR
VBO
Each device in the Z8 Encore! XP
POR circuit monitors the supply voltage and holds the device in the Reset state until the
supply voltage reaches a safe operating level. After the supply voltage exceeds the POR
voltage threshold (V
oscillator. After the POR counter times out, the XTAL Counter is enabled to count a total
of 16 system clock pulses. The device is held in the Reset state until both the POR Counter
and XTAL counter have timed out. After the Z8 Encore! XP F0822 Series device exits the
POR state, the eZ8 CPU fetches the Reset vector. Following POR, the POR status bit in the
Watchdog Timer Control Register (WDTCTL) is set to 1.
Figure 6
(V
The devices in Z8 Encore! XP F0822 Series provide low Voltage Brownout 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
POR
).
displays POR operation. See
Oscillator
Start-up
Figure 6. Power-On Reset Operation
POR
), the POR Counter is enabled and counts 66 cycles of the WDT
Counter Delay
POR
®
F0822 Series contains an internal POR circuit. The
Electrical Characteristics
Counter Delay
XTAL
Z8 Encore! XP
Reset and Stop Mode Recovery
for POR threshold voltage
Product Specification
Execution
Program
®
F0822 Series
V
CC
= 3.3 V
41