AT89S8253-24PU Atmel, AT89S8253-24PU Datasheet - Page 16

• Manufacturer Part Number: AT89S8253-24PU
• Description: IC 8051 MCU FLASH 12K 40DIP
• Manufacturer: Atmel
• Series: 89Sr

Specifications of AT89S8253-24PU

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 24MHz
• Connectivity: SPI, UART/USART
• Peripherals: POR, WDT
• Number Of I /o: 32
• Program Memory Size: 12KB (12K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Cpu Family: 89S
• Device Core: 8051
• Device Core Size: 8b
• Frequency (max): 24MHz
• Interface Type: SPI/UART
• Total Internal Ram Size: 256Byte
• # 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: Through Hole
• Pin Count: 40
• Package Type: PDIP
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Maximum Clock Frequency: 24 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: Through Hole
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: AT89ISP
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -
• Lead Free Status / Rohs Status: Compliant

Figure 10-1. Timer 2 in Capture Mode
10.3
Table 10-3.
16
T2MOD Address = 0C9H
Not Bit Addressable
Symbol
–
T2OE
DCEN
Bit
T2EX PIN
Auto-reload (Up or Down Counter)
AT89S8253
OSC
Function
Not implemented, reserved for future use.
Timer 2 Output Enable bit.
When set, this bit allows Timer 2 to be configured as an up/down counter.
–
7
T2MOD – Timer 2 Mode Control Register
T2 PIN
÷12
Timer 2 can be programmed to count up or down when configured in its 16-bit auto-reload
mode. This feature is invoked by the DCEN (Down Counter Enable) bit located in the SFR
T2MOD (see
count up. When DCEN is set, Timer 2 can count up or down, depending on the value of the
T2EX pin.
Figure 10-2
are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to 0FFFFH and then sets
the TF2 bit upon overflow. The overflow also causes the timer registers to be reloaded with the
16-bit value in RCAP2H and RCAP2L. The values in RCAP2H and RCAP2L are preset by soft-
ware. If EXEN2 = 1, a 16-bit reload can be triggered either by an overflow or by a 1-to-0
transition at external input T2EX. This transition also sets the EXF2 bit. Both the TF2 and EXF2
bits can generate an interrupt if enabled.
Setting the DCEN bit enables Timer 2 to count up or down, as shown in
mode, the T2EX pin controls the direction of the count. A logic 1 at T2EX makes Timer 2 count
up. The timer will overflow at 0FFFFH and set the TF2 bit. This overflow also causes the 16-bit
–
6
TRANSITION
DETECTOR
shows Timer 2 automatically counting up when DCEN = 0. In this mode, two options
C/T2 = 0
C/T2 = 1
Table
–
5
10-3). Upon reset, the DCEN bit is set to 0 so that timer 2 will default to
EXEN2
–
4
TR2
CAPTURE
CONTROL
CONTROL
–
3
RCAP2H
TH2
EXF2
RCAP2L
–
2
TL2
Reset Value = XXXX XX00B
OVERFLOW
T2OE
1
TF2
Figure
INTERRUPT
DCEN
TIMER 2
0
3286P–MICRO–3/10
10-3. In this