TS80C51RA2-VCB Atmel, TS80C51RA2-VCB Datasheet - Page 18

• Manufacturer Part Number: TS80C51RA2-VCB
• Description: IC MCU 8BIT 256BYTE 40MHZ 44PLCC
• Manufacturer: Atmel
• Series: 80Cr

Specifications of TS80C51RA2-VCB

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40/30MHz
• Connectivity: UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Type: ROMless
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 44-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -

TS80C51RA2/RD2
TS83C51RB2/RC2/RD2
TS87C51RB2/RC2/RD2
6.4. Timer 2
The timer 2 in the
It is a 16-bit timer/counter: the count is maintained by two eight-bit timer registers, TH2 and TL2, connected in
cascade. It is controlled by T2CON register (See Table 6) and T2MOD register (See Table 7). Timer 2 operation
is similar to Timer 0 and Timer 1. C/T2 selects F
as the timer clock input. Setting TR2 allows TL2 to be incremented by the selected input.
Timer 2 has 3 operating modes: capture, autoreload and Baud Rate Generator. These modes are selected by the
combination of RCLK, TCLK and CP/RL2 (T2CON), as described in the Atmel Wireless & Microcontrollers 8-
bit Microcontroller Hardware description.
Refer to the Atmel Wireless & Microcontrollers 8-bit Microcontroller Hardware description for the description of
Capture and Baud Rate Generator Modes.
In
6.4.1. Auto-Reload Mode
The auto-reload mode configures timer 2 as a 16-bit timer or event counter with automatic reload. If DCEN bit
in T2MOD is cleared, timer 2 behaves as in 80C52 (refer to the Atmel Wireless & Microcontrollers 8-bit
Microcontroller Hardware description). If DCEN bit is set, timer 2 acts as an Up/down timer/counter as shown in
Figure 5. 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 the direction of the count. EXF2
does not generate any interrupt. This bit can be used to provide 17-bit resolution.
18
TS80C51RX2
Auto-reload mode with up or down counter
Programmable clock-output
Timer 2 includes the following enhancements:
TS80C51RX2
is compatible with the timer 2 in the 80C52.
OSC
/12 (timer operation) or external pin T2 (counter operation)
Rev. C - 06 March, 2001