AT89C5131A-M Atmel Corporation, AT89C5131A-M Datasheet - Page 58

• Manufacturer Part Number: AT89C5131A-M
• Manufacturer: Atmel Corporation

Specifications of AT89C5131A-M

• Flash (kbytes): 32 Kbytes
• Max. Operating Frequency: 48 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Eeprom (bytes): 1024
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART/USB
• Watchdog: Yes

14. Programmable Counter Array (PCA)
58
AT89C5130A/31A-M
The PCA provides more timing capabilities with less CPU intervention than the standard
timer/counters. Its advantages include reduced software overhead and improved accuracy. 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 one of the following
signals:
Each compare/capture modules can be programmed in any one of the following modes:
Module 4 can also be programmed as a watchdog timer (see Section "PCA Watchdog Timer",
page 68).
When the compare/capture modules are programmed in the 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/O. These pins
are listed below. If the port pin 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 14-1). The timer count
source is determined from the CPS1 and CPS0 bits in the CMOD register (Table 14-1) and can
be programmed to run at:
PCA Component
16-bit Counter
16-bit Module 0
16-bit Module 1
16-bit Module 2
16-bit Module 3
16-bit Module 4
• Peripheral clock frequency (F
• Peripheral clock frequency (F
• Timer 0 overflow
• External input on ECI (P1.2)
• rising and/or falling edge capture,
• software timer
• high-speed output, or
• pulse width modulator
• 1/6 the
• 1/2 the
• The Timer 0 overflow
• The input on the ECI pin (P1.2)
peripheral clock frequency (F
peripheral clock frequency (F
CLK PERIPH
CLK PERIPH
)
)
External I/O Pin
P1.2/ECI
P1.3/CEX0
P1.4/CEX1
P1.5/CEX2
P1.6/CEX3
P1.7/CEX4
CLK PERIPH
CLK PERIPH
÷
÷
2
6
)
)
.
.
4337K–USB–04/08