SN8P2604A
8-Bit Micro-Controller
3.4.2 THE SYSTEM OPERATING VOLTAGE DECSRIPTION
To improve the brown out reset needs to know the system minimum operating voltage which is depend on the system
executing rate and power level. Different system executing rates have different system minimum operating voltage.
The electrical characteristic section shows the system voltage to executing rate relationship.
System Mini.
Operating Voltage.
Vdd (V)
Normal Operating
Area
Dead-Band Area
System Reset
Voltage.
Reset Area
System Rate (Fcpu)
Normally the system operation voltage area is higher than the system reset voltage to VDD, and the reset voltage is
decided by LVD detect level. The system minimum operating voltage rises when the system executing rate upper even
higher than system reset voltage. The dead-band definition is the system minimum operating voltage above the system
reset voltage.
3.4.3 BROWN OUT RESET IMPROVEMENT
How to improve the brown reset condition? There are some methods to improve brown out reset as following.
z
z
z
z
LVD reset
Watchdog reset
Reduce the system executing rate
External reset circuit. (Zener diode reset circuit, Voltage bias reset circuit, External reset IC)
Note:
1. The “ Zener diode reset circuit”, “Voltage bias reset circuit” and “External reset IC” can
completely improve the brown out reset, DC low battery and AC slow power down conditions.
2. For AC power application and enhance EFT performance, the system clock is 4MHz/4 (1 mips)
and use external reset (“ Zener diode reset circuit”, “Voltage bias reset circuit”, “External reset
IC”). The structure can improve noise effective and get good EFT characteristic.
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