AT89C51RE2 Atmel Corporation, AT89C51RE2 Datasheet - Page 164

• Manufacturer Part Number: AT89C51RE2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RE2

• Flash (kbytes): 128 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Spi: 1
• Uart: 2
• Sram (kbytes): 8.25
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART/OCD
• Watchdog: Yes

Reset
Introduction
Reset Input
164
AT89C51RE2
The reset sources are: Power Management, Hardware Watchdog, PCA Watchdog and Reset
input.
Figure 68. Reset schematic
The Reset input can be used to force a reset pulse longer than the internal reset controlled by
the Power Monitor. RST input has a pull-down resistor allowing power-on reset by simply con-
necting an external capacitor to V
characteristics are discussed in the Section “DC Characteristics” of the AT89C51RE2 datasheet.
Figure 69. Reset Circuitry and Power-On Reset
RST
RST
Watchdog
Watchdog
Hardware
a. RST input circuitry
Monitor
VSS
Power
PCA
CC
as shown in Figure 69. Resistor value and input
To internal reset
b. Power-on Reset
Internal Reset
VDD
+
RST
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