AT89LP6440-20AU Atmel, AT89LP6440-20AU Datasheet - Page 58

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

Specifications of AT89LP6440-20AU

• 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-TQFP, 44-VQFP
• Package: 44TQFP
• Device Core: 8051
• Family Name: 89LP
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 2.5|3.3 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 38
• Interface Type: 2-Wire/SPI
• On-chip Dac: 8-chx10-bit
• Number Of Timers: 3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

11.5.4
58
AT89LP6440 - Preliminary
Mode 3 – Split 8-bit PWM
Timer 1 in PWM Mode 3 simply holds its count. The effect is the same as setting TR1 = 0.
Timer 0 in PWM Mode 3 establishes TL0 and TH0 as two separate PWM counters in a manner
similar to normal Mode 3. PWM Mode 3 on Timer 0 is shown in
Prescaler is available to change the output frequency during PWM Mode 3. TL0 can use the
Timer 0 control bits: GATE, TR0, INT0, PWM0EN and TF0. TH0 is locked into a timer function
and uses TR1, PWM1EN and TF1. RL0 provides the duty cycle for TL0 and RH0 provides the
duty cycle for TH0.
PWM Mode 3 is for applications requiring a single PWM channel and two timers, or two PWM
channels and an extra timer or counter. With Timer 0 in PWM Mode 3, the AT89LP6440 can
appear to have four Timer/Counters. When Timer 0 is in PWM Mode 3, Timer 1 can be turned on
and off by switching it out of and into its own Mode 3. In this case, Timer 1 can still be used by
the serial port as a baud rate generator or in any application not requiring an interrupt. The fol-
lowing formulas give the output frequency and duty cycle for Timer 0 in PWM Mode 3.
Figure 11-10. Timer/Counter 0 PWM Mode 3
INT0 Pin
GATE0
Mode 3:
Mode 3, T1:
Mode 3, T0:
TR0
OSC
OSC
TR1
f
out
÷TPS
÷TPS
Duty Cycle %
Duty Cycle %
=
Oscillator Frequency
------------------------------------------------------ -
Control
256
=
=
100
100
(8 Bits)
(8 Bits)
(8 Bits)
(8 Bits)
OCR0
OCR1
RL0
RH0
TL0
TH0
×
×
RH0
----------- -
RL0
---------- -
256
256
×
=
=
-------------------- -
TPS
1
+
Figure
1
11-10. Only the Timer
T0
T1
3706A–MICRO–9/09