AT80C51RD2-3CSIM Atmel, AT80C51RD2-3CSIM Datasheet - Page 18

• Manufacturer Part Number: AT80C51RD2-3CSIM
• Description: IC MCU 8051 5V SPI 20MHZ 40-DIP
• Manufacturer: Atmel
• Series: 80Cr

Specifications of AT80C51RD2-3CSIM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Type: ROMless
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -

Figure 9-1.
9.2
18
Programmable Clock-Output
AT80C51RD2
F
Auto-Reload Mode Up/Down Counter (DCEN = 1)
CLK PERIPH
In the clock-out mode, Timer 2 operates as a 50% duty-cycle, programmable clock generator
(see Figure 9-2). The input clock increments TL2 at frequency F
edly counts to overflow from a loaded value. At overflow, the contents of RCAP2H and RCAP2L
registers are loaded into TH2 and TL2. In this mode, Timer 2 overflows do not generate inter-
rupts. The formula gives the clock-out frequency as a function of the system oscillator frequency
and the value in the RCAP2H and RCAP2L registers:
For a 16 MHz system clock, Timer 2 has a programmable frequency range of 61 Hz
(F
(P1.0).
Timer 2 is programmed for the clock-out mode as follows:
• Set T2OE bit in T2MOD register.
• Clear C/T2 bit in T2CON register.
• Determine the 16-bit reload value from the formula and enter it in RCAP2H/RCAP2L
• Enter a 16-bit initial value in timer registers TH2/TL2. It can be the same as the reload value
• To start the timer, set TR2 run control bit in T2CON register.
CLK PERIPH
registers.
or a different one depending on the application.
/2
16)
to 4 MHz (F
Clock OutFrequency
:6
–
(UP COUNTING RELOAD VALUE)
CLK PERIPH
(DOWN COUNTING RELOAD VALUE)
RCAP2L
T2
(8-bit)
(8-bit)
(8-bit)
TL2
FFh
/4). The generated clock signal is brought out to T2 pin
T2CON
=
RCAP2H
C/T2
(8-bit)
(8-bit)
TH2
(8-bit)
0
FFh
1
---------------------------------------------------------------------------------------- -
4
×
(
65536 RCAP2H
T2CON
TR2
F
–
CLKPERIPH
T2EX:
if DCEN = 1, 1 = UP
if DCEN = 1, 0 = DOWN
if DCEN = 0, up counting
T2CON
TOGGLE
TF2
CLK PERIPH
⁄
RCAP2L
T2CON
EXF2
INTERRUPT
TIMER 2
/2. The timer repeat-
)
4113D–8051–01/09