AT80C51RD2-SLSUM Atmel, AT80C51RD2-SLSUM Datasheet - Page 20

• Manufacturer Part Number: AT80C51RD2-SLSUM
• Description: MCU, 8BIT, 8051, 5V, SPI, 20MHZ, 44PLCC
• Manufacturer: Atmel

Specifications of AT80C51RD2-SLSUM

• Controller Family/series: (8051) 8052
• No. Of I/o's: 32
• Ram Memory Size: 1280Byte
• Cpu Speed: 40MHz
• No. Of Timers: 3
• No. Of Pwm Channels: 5
• Core Size: 8bit
• Oscillator Type: External Only
• Processor Series: AT80x
• Core: 8051
• Data Bus Width: 8 bit
• Program Memory Type: ROMLess
• Data Ram Size: 1280 B
• Interface Type: UART, SPI
• Maximum Clock Frequency: 60 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: PLCC
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Minimum Operating Temperature: - 40 C
• Cpu Family: AT80
• Device Core: 8051
• Device Core Size: 8b
• Frequency (max): 40MHz
• Program Memory Size: Not Required
• Total Internal Ram Size: 1.25KB
• # I/os (max): 32
• 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
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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