AT89C51RB2-3CSIM Atmel, AT89C51RB2-3CSIM Datasheet - Page 17

• Manufacturer Part Number: AT89C51RB2-3CSIM
• Description: IC 8051 MCU FLASH 16K 40DIP
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51RB2-3CSIM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 60MHz
• Connectivity: SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Data Bus Width: 8 bit
• Data Ram Size: 1.25 KB
• Interface Type: SPI, UART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• For Use With: AT89STK-11 - KIT STARTER FOR AT89C51RX2
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: No

Figure 6. Mode Switching Waveforms
4180E–8051–10/06
XTAL1
XTAL1:2
X2 Bit
CPU Clock
x1 Mode
The X2 bit in the CKCON0 register (see Table 15) allows a switch from 12 clock periods
per instruction to 6 clock periods and vice versa. At reset, the speed is set according to
X2 bit of Hardware Security Byte (HSB). By default, Standard mode is active. Setting the
X2 bit activates the X2 feature (X2 mode).
The T0X2, T1X2, T2X2, UARTX2, PCAX2, and WDX2 bits in the CKCON0 register
(Table 15) and SPIX2 bit in the CKCON1 register (see Table 16) allow a switch from
standard peripheral speed (12 clock periods per peripheral clock cycle) to fast periph-
eral speed (6 clock periods per peripheral clock cycle). These bits are active only in X2
mode.
F
OSC
X2 Mode
AT89C51RB2/RC2
X1 Mode
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