TS80C51RA2-VCA Atmel, TS80C51RA2-VCA Datasheet - Page 20

• Manufacturer Part Number: TS80C51RA2-VCA
• Description: IC MCU 8BIT 256BYTE 40MHZ 40-DIP
• Manufacturer: Atmel
• Series: 80Cr

Specifications of TS80C51RA2-VCA

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40/30MHz
• Connectivity: UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Type: ROMless
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°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 6-2.
6.2.2
20
AT/TS8xC51Rx2
Programmable Clock-Output
Auto-reload Mode Up/Down Counter (DCEN = 1)
XTAL1
In the clock-out mode, timer 2 operates as a 50%-duty-cycle, programmable clock generator
(See Figure 6-3) . The input clock increments TL2 at frequency F
counts to overflow from a loaded value. At overflow, the contents of RCAP2H and RCAP2L reg-
isters are loaded into TH2 and TL2. In this mode, timer 2 overflows do not generate interrupts.
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
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.
OSC
registers.
or a different one depending on the application.
F
XTAL
/2
16)
to 4 MHz (F
Clock OutFrequency
OSC
F
OSC
–
/4). The generated clock signal is brought out to T2 pin (P1.0).
(DOWN COUNTING RELOAD VALUE)
(:6 in X2 mode)
(UP COUNTING RELOAD VALUE)
RCAP2L
T2
:12
(8-bit)
(8-bit)
(8-bit)
TL2
FFh
=
---------------------------------------------------------------------------------------- -
4
T2CONreg
RCAP2H
C/T2
(8-bit)
(8-bit)
×
TH2
(8-bit)
0
FFh
1
(
65536 RCAP2H
T2CONreg
–
TR2
F
osc
T2EX:
if DCEN=1, 1=UP
if DCEN=1, 0=DOWN
if DCEN = 0, up
counting
TOGGLE
T2CONreg
OSC
TF2
⁄
RCAP2L
/2. The timer repeatedly
T2CONreg
EXF2
INTERRUPT
TIMER 2
)
4188F–8051–01/08