Z8F042ASJ020EG2156 Datasheet, PDF (42/280 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
26
V_CC = 3.3 V
V_POR
V_VBO
Program
Execution
Voltage
Brown-Out
V_CC = 3.3V
Program
Execution
System Clock
Internal RESET
signal
Note: Not to Scale
POR
counter delay
Figure 6. Voltage Brown-Out Reset Operation
The POR level is greater than the VBO level by the specified hysteresis value. This
ensures that the device undergoes a Power-On Reset after recovering from a VBO condi-
tion.
Watchdog Timer Reset
If the device is operating in Normal or Halt Mode, the Watchdog Timer can initiate a Sys-
tem Reset at time-out if the WDT_RES Flash option bit is programmed to 1, i.e., the
unprogrammed state of the WDT_RES Flash option bit. If the bit is programmed to 0, it
configures the Watchdog Timer to cause an interrupt, not a System Reset, at time-out.
The WDT bit in the Reset Status (RSTSTAT) Register is set to signify that the reset was
initiated by the Watchdog Timer.
External Reset Input
The RESET pin has a Schmitt-Triggered input and an internal pull-up resistor. Once the
RESET pin is asserted for a minimum of four system clock cycles, the device progresses
through the System Reset sequence. Because of the possible asynchronicity of the system
clock and reset signals, the required reset duration may be as short as three clock periods
PS022828-0413
PRELIMINARY
Reset Sources