AT89C51AC2-RLTUM Atmel, AT89C51AC2-RLTUM Datasheet - Page 75

• Manufacturer Part Number: AT89C51AC2-RLTUM
• Description: IC 8051 MCU FLASH 32K 44VQFP
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C51AC2-RLTUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 1280 B
• Interface Type: UART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 34
• Number Of Timers: 3
• Operating Supply Voltage: 3 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• For Use With: AT89OCD-01 - USB EMULATOR FOR AT8XC51 MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Programmable
Counter Array (PCA)
PCA Timer
4127H–8051–02/08
The PCA provides more timing capabilities with less CPU intervention than the standard
timer/counters. Its advantages include reduced software overhead and improved accu-
racy. The PCA consists of a dedicated timer/counter which serves as the time base for
an array of five compare/capture modules. Its clock input can be programmed to count
any of the following signals:
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•
•
•
Each compare/capture modules can be programmed in any one of the following modes:
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•
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Module 4 can also be programmed as a Watchdog timer. see the "PCA Watchdog
Timer" section.
When the compare/capture modules are programmed in capture mode, software timer,
or high speed output mode, an interrupt can be generated when the module executes its
function. All five modules plus the PCA timer overflow share one interrupt vector.
The PCA timer/counter and compare/capture modules share Port 1 for external I/Os.
These pins are listed below. If the port is not used for the PCA, it can still be used for
standard I/O.
The PCA timer is a common time base for all five modules (see Figure 39). The timer
count source is determined from the CPS1 and CPS0 bits in the CMOD SFR (see Table
8) and can be programmed to run at:
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•
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PCA clock frequency/6 (see “clock” section)
PCA clock frequency/2
Timer 0 overflow
External input on ECI (P1.2)
rising and/or falling edge capture,
software timer,
high-speed output,
pulse width modulator.
1/6 the PCA clock frequency.
1/2 the PCA clock frequency.
the Timer 0 overflow.
the input on the ECI pin (P1.2).
PCA Component
16-bit Module 0
16-bit Module 1
16-bit Module 2
16-bit Module 3
16-bit Module 4
16-bit Counter
External I/O Pin
P1.3/CEX0
P1.4/CEX1
P1.5/CEX2
P1.6/CEX3
P1.7/CEX4
P1.2/ECI
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