AT89LP52-20PU Atmel, AT89LP52-20PU Datasheet - Page 55

• Manufacturer Part Number: AT89LP52-20PU
• Description: IC MCU 8051 8K FLASH SPI 40PDIP
• Manufacturer: Atmel
• Series: 89LPr

Specifications of AT89LP52-20PU

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.4 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: Serial
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 36
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details

Figure 12-6. Timer 2 in Baud Rate Generator Mode
12.5
Figure 12-7. Timer 2 in Clock-out Mode
3709B–MICRO–12/10
Frequency Generator (Programmable Clock Out)
T2EX PI N
OSC
T2 PI N
T2EX PIN
T2 PIN
÷CDV
Timer 2 can generate a 50% duty cycle clock on T2 (P1.0), as shown in
besides being a regular I/O pin, has two alternate functions. It can be programmed to input the
external clock for Timer/Counter 2 or to toggle its output at every timer overflow. To configure
the Timer/Counter 2 as a clock generator, bit C/T2 (T2CON.1) must be cleared and bit T2OE
(T2MOD.1) must be set. Bit TR2 (T2CON.2) starts and stops the timer. The clock-out frequency
depends on the system frequency and the reload value of Timer 2 capture registers (RCAP2H,
RCAP2L), as shown in the following equation.
In the frequency generator mode, Timer 2 roll-overs will not generate an interrupt. This behavior
is similar to when Timer 2 is used as a baud-rate generator. It is possible to use Timer 2 as a
baud-rate generator and a clock generator simultaneously. Note, however, that the baud-rate
and clock-out frequencies cannot be determined independently from one another since they
both use RCAP2H and RCAP2L.
OSC
TRANSITION
DETECT OR
C/T2 = 0
C/T2 = 1
÷CDV
TRANSITION
DETECTOR
Clock Out Frequency
EXEN2
TR2
C/T2
EXEN2
TR2
RCAP2L
TL2
EXF2
=
RCAP2H
------------------------------------------------------------------------------------------- -
2
TH2
AT89LP51/52 - Preliminary
×
RCAP2L
TL2
[
÷2
65536
EXF2
System Frequency
INTERR UPT
TIMER 2
RCAP2H
–
÷
TH2
(
2
RCAP2H,RCAP2L
"1"
"1"
TIMER 1 OVERFLOW
"0"
"0"
"0"
T2OE
INTERRUPT
TIMER 2
"1"
÷
SMOD1
RCLK
TCLK
÷
16
16
)
]
Figure
CLOCK
CLOCK
Rx
Tx
13.. This pin,
55