AT89C51RE2-SLSUM Atmel, AT89C51RE2-SLSUM Datasheet - Page 70

• Manufacturer Part Number: AT89C51RE2-SLSUM
• Description: MCU 8BIT FLASH 2.7-5.5V 44-PLCC
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51RE2-SLSUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 60MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Ram Size: 8K 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
• Package: 44PLCC
• Device Core: 8051
• Family Name: 89C
• Maximum Speed: 40 MHz
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 34
• Interface Type: SPI/TWI/UART
• Number Of Timers: 3
• Processor Series: AT89x
• Core: 8051
• Data Ram Size: 8 KB
• Maximum Clock Frequency: 40 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: AT89OCD-01
• Minimum Operating Temperature: - 40 C
• Cpu Family: 89C
• Device Core Size: 8b
• Frequency (max): 40MHz
• Total Internal Ram Size: 8KB
• # I/os (max): 34
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: PLCC
• 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: Lead free / RoHS Compliant

Mode 2 (8-bit Timer
with Auto-Reload)
Figure 25. Timer/Counter x (x = 0 or 1) in Mode 2
Mode 3 (Two 8-bit
Timers)
Figure 26. Timer/Counter 0 in Mode 3: Two 8-bit Counters
70
INT0#
See the “Clock” section
See the “Clock” section
INTx#
AT89C51RE2
CLOCK
CLOCK
CLOCK
T0
FTx
Tx
FTx
FTx
TMOD reg
GATEx
GATE0
TMOD.3
÷ 6
÷ 6
÷ 6
Mode 2 configures Timer 0 as an 8-bit Timer (TL0 register) that automatically reloads from TH0
register (see Figure 25). TL0 overflow sets TF0 flag in TCON register and reloads TL0 with the
contents of TH0, which is preset by software. When the interrupt request is serviced, hardware
clears TF0. The reload leaves TH0 unchanged. The next reload value may be changed at any
time by writing it to TH0 register.
Mode 3 configures Timer 0 such that registers TL0 and TH0 operate as separate 8-bit Timers
(see Figure 26). This mode is provided for applications requiring an additional 8-bit Timer or
Counter. TL0 uses the Timer 0 control bits C/T0# and GATE0 in TMOD register, and TR0 and
TF0 in TCON register in the normal manner. TH0 is locked into a Timer function (counting F
/6) and takes over use of the Timer 1 interrupt (TF1) and run control (TR1) bits. Thus, operation
of Timer 1 is restricted when Timer 0 is in mode 3.
TMOD reg
TMOD.2
C/T0#
C/Tx#
0
1
0
1
TCON reg
TCON.4
TR0
TRx
TCON.6
TR1
(8 bits)
(8 bits)
(8 bits)
(8 bits)
TH0
THx
TLx
TL0
Overflow
Overflow
Overflow
TCON reg
TCON.5
TCON.7
TFx
TF0
TF1
Timer x
Interrupt
Request
Timer 0
Interrupt
Request
Timer 1
Interrupt
Request
7663E–8051–10/08
PER