AT89C51ID2-SMSIM ATMEL [ATMEL Corporation], AT89C51ID2-SMSIM Datasheet - Page 32

• Manufacturer Part Number: AT89C51ID2-SMSIM
• Description: 8-bit Flash Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

Reset
Introduction
Reset Input
32
AT89C51ID2
The reset sources are : Power Management, Hardware Watchdog, PCA Watchdog and
Reset input.
Figure 8. Reset schematic
The Reset input can be used to force a reset pulse longer than the internal reset con-
trolled by the Power Monitor. RST input has a pull-down resistor allowing power-on
reset by simply connecting an external capacitor to V
value and input characteristics are discussed in the Section “DC Characteristics” of the
AT89C51ID2 datasheet.
Figure 9. Reset Circuitry and Power-On Reset
RST
RST
Watchdog
Watchdog
Hardware
a. RST input circuitry
Monitor
VSS
Power
PCA
To internal reset
CC
as shown in Figure 9. Resistor
b. Power-on Reset
Internal Reset
VDD
+
4289A–8051–09/03
RST