AT89C5131-S3SIL Atmel, AT89C5131-S3SIL Datasheet - Page 49

• Manufacturer Part Number: AT89C5131-S3SIL
• Description: IC 8051 MCU FLASH 32K USB 52PLCC
• Manufacturer: Atmel
• Series: AT89C513xr

Specifications of AT89C5131-S3SIL

• Core Processor: C52X2
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: LED, POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 52-PLCC
• For Use With: AT89STK-10 - KIT EVAL APPL MASS STORAGEAT89STK-05 - KIT STARTER FOR AT89C5131
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Data Converters: -

Timer 2
Auto-reload Mode
4136B–USB–09/03
The Timer 2 in the AT89C5131 is the standard C52 Timer 2. It is a 16-bit timer/counter:
the count is maintained by two cascaded eight-bit timer registers, TH2 and TL2. It is
controlled by T2CON (Table 47) and T2MOD (Table 48) registers. Timer 2 operation is
similar to Timer 0 and Timer 1. C/T2 selects F
(counter operation) as the timer clock input. Setting TR2 allows TL2 to be incremented
by the selected input.
Timer 2 has 3 operating modes: capture, auto reload and Baud Rate Generator. These
modes are selected by the combination of RCLK, TCLK and CP/RL2 (T2CON).
Refer to the Atmel 8-bit microcontroller hardware documentation for the description of
Capture and Baud Rate Generator Modes.
Timer 2 includes the following enhancements:
•
•
The Auto-reload mode configures Timer 2 as a 16-bit timer or event counter with auto-
matic reload. If DCEN bit in T2MOD is cleared, Timer 2 behaves as in 80C52 (refer to
the Atmel 8-bit microcontroller hardware description). If DCEN bit is set, Timer 2 acts as
an Up/down timer/counter as shown in Figure 23. In this mode the T2EX pin controls the
direction of count.
When T2EX is high, Timer 2 counts up. Timer overflow occurs at FFFFh which sets the
TF2 flag and generates an interrupt request. The overflow also causes the 16-bit value
in RCAP2H and RCAP2L registers to be loaded into the timer registers TH2 and TL2.
When T2EX is low, Timer 2 counts down. Timer underflow occurs when the count in the
timer registers TH2 and TL2 equals the value stored in RCAP2H and RCAP2L registers.
The underflow sets TF2 flag and reloads FFFFh into the timer registers.
The EXF2 bit toggles when Timer 2 overflows or underflows according to the direction of
the count. EXF2 does not generate any interrupt. This bit can be used to provide 17-bit
resolution.
Auto-reload mode with up or down counter
Programmable Clock-output
OSC
/12 (timer operation) or external pin T2
AT89C5131
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