AT89C51RD2 Atmel Corporation, AT89C51RD2 Datasheet - Page 33

• Manufacturer Part Number: AT89C51RD2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RD2

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 2
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

4235K–8051–05/08
Reset Value = 0000 0000b
Bit addressable
Number
Bit
7
6
5
4
3
2
1
0
Mnemonic
CP/RL2#
EXEN2
C/T2#
RCLK
TCLK
EXF2
TR2
TF2
Bit
Description
Timer 2 overflow Flag
Must be cleared by software.
Set by hardware on Timer 2 overflow, if RCLK = 0 and TCLK = 0.
Timer 2 External Flag
Set when a capture or a reload is caused by a negative transition on T2EX pin if EXEN2
= 1.
When set, causes the CPU to vector to Timer 2 interrupt routine when Timer 2 interrupt
is enabled.
Must be cleared by software. EXF2 doesn’t cause an interrupt in Up/down counter mode
(DCEN = 1).
Receive Clock bit
Cleared to use timer 1 overflow as receive clock for serial port in mode 1 or 3.
Set to use Timer 2 overflow as receive clock for serial port in mode 1 or 3.
Transmit Clock bit
Cleared to use timer 1 overflow as transmit clock for serial port in mode 1 or 3.
Set to use Timer 2 overflow as transmit clock for serial port in mode 1 or 3.
Timer 2 External Enable bit
Cleared to ignore events on T2EX pin for Timer 2 operation.
Set to cause a capture or reload when a negative transition on T2EX pin is detected, if
Timer 2 is not used to clock the serial port.
Timer 2 Run control bit
Cleared to turn off Timer 2.
Set to turn on Timer 2.
Timer/Counter 2 select bit
Cleared for timer operation (input from internal clock system: F
Set for counter operation (input from T2 input pin, falling edge trigger). Must be 0 for
clock out mode.
Timer 2 Capture/Reload bit
If RCLK = 1 or TCLK = 1, CP/RL2# is ignored and timer is forced to auto-reload on Timer
2 overflow.
Cleared to auto-reload on Timer 2 overflows or negative transitions on T2EX pin if
EXEN2=1.
Set to capture on negative transitions on T2EX pin if EXEN2 = 1.
AT89C51RD2/ED2
CLK PERIPH
).
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