AT89LP6440-20MU Atmel, AT89LP6440-20MU Datasheet - Page 64

• Manufacturer Part Number: AT89LP6440-20MU
• Description: MCU 8051 64K FLASH ISP 44VQFN
• Manufacturer: Atmel
• Series: 89LPr

Specifications of AT89LP6440-20MU

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 38
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 8K x 8
• Ram Size: 4.25K x 8
• Voltage - Supply (vcc/vdd): 2.4 V ~ 3.6 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-VQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 12-4. Timer 2 Diagram: Auto-Reload Mode (T2CM
Figure 12-5. Timer 2 Diagram: Auto-Reload Mode (T2CM
64
AT89LP6440 - Preliminary
÷TPS
÷TPS
registers, TH2 and TL2, respectively. A logic 0 at T2EX makes Timer 2 count down. The timer
underflows when TH2 and TL2 equal BOTTOM, the 16-bit value stored in RCAP2H and
RCAP2L. The underflow sets the TF2 bit and causes MAX to be reloaded into the timer regis-
ters. The EXF2 bit toggles whenever Timer 2 overflows or underflows and can be used as a 17th
bit of resolution. In this operating mode, EXF2 does not flag an interrupt.
When T2EX = 1 and T2CM
overflow also causes MIN to be reloaded into the timer registers. A logic 0 at T2EX makes Timer
2 count down. The timer underflows when TH2 and TL2 equal MIN. The underflow sets the TF2
bit and causes TOP to be reloaded into the timer registers. The behavior of Count Mode 0 ver-
sus Count Mode 0 when DCEN is enabled is shown in
The timer overflow/underflow rate for up-down counting mode is the same as for up counting
mode, provided that the count direction does not change. Changes to the count direction may
result in longer or shorter periods between time-outs.
1-0
= 01B, the timer will overflow at TOP and set the TF2 bit. This
1-0
1-0
= 00B, DCEN = 1)
= 01B, DCEN = 1)
Figure
12-6.
3706A–MICRO–9/09