AT89C51RD2-SLSUM Atmel, AT89C51RD2-SLSUM Datasheet - Page 26

• Manufacturer Part Number: AT89C51RD2-SLSUM
• Description: IC 8051 MCU FLASH 64K 44PLCC
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51RD2-SLSUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 60MHz
• Connectivity: SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-PLCC
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: UART, SPI
• Maximum Clock Frequency: 60 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Minimum Operating Temperature: - 40 C
• Package: 44PLCC
• Device Core: 80C51
• Family Name: 89C
• Maximum Speed: 40 MHz
• For Use With: AT89OCD-01 - USB EMULATOR FOR AT8XC51 MCUAT89STK-11 - KIT STARTER FOR AT89C51RX2
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details

10. Reset
10.1
10.2
10.3
26
Introduction
Reset Input
Reset Output
AT89C51RD2/ED2
The reset sources are: Power Management, Hardware Watchdog, PCA Watchdog and Reset
input.
Figure 10-1. 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 AT89C51RD2/ED2
datasheet.
Figure 10-2. Reset Circuitry and Power-On Reset
Reset output can be generated by two sources:
As detailed in Section “Hardware Watchdog Timer”, page 84, the WDT generates a 96-clock
period pulse on the RST pin.
In order to properly propagate this pulse to the rest of the application in case of external capaci-
tor or power-supply supervisor circuit, a 1 kΩ resistor must be added as shown Figure 10-3.
• Internal POR/PFD
• Hardware watchdog timer
RST
RST
Watchdog
Watchdog
Hardware
a. RST input circuitry
Monitor
VSS
Power
PCA
CC
as shown in Figure 10-2. Resistor value and input
To internal reset
b. Power-on Reset
Internal Reset
VDD
+
RST
4235K–8051–05/08