ATtiny43U Atmel Corporation, ATtiny43U Datasheet - Page 87

• Manufacturer Part Number: ATtiny43U
• Manufacturer: Atmel Corporation

Specifications of ATtiny43U

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 8 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 4
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.25
• Eeprom (bytes): 64
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 0.7 to 5.5
• Operating Voltage (vcc): 0.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

12.7.4
8048B–AVR–03/09
Phase Correct PWM Mode
in a constantly high or low output (depending on the polarity of the output set by the COMnA1:0
bits.)
A frequency (with 50% duty cycle) waveform output in fast PWM mode can be achieved by set-
ting OCnx to toggle its logical level on each Compare Match (COMnx1:0 = 1). The waveform
generated will have a maximum frequency of f
feature is similar to the OCnA toggle in CTC mode, except the double buffer feature of the Out-
put Compare unit is enabled in the fast PWM mode.
The phase correct PWM mode (WGMn2:0 = 1 or 5) provides a high resolution phase correct
PWM waveform generation option. The phase correct PWM mode is based on a dual-slope
operation. The counter counts repeatedly from BOTTOM to TOP and then from TOP to BOT-
TOM. TOP is defined as 0xFF when WGMn2:0 = 1, and OCRnA when WGMn2:0 = 5. In non-
inverting Compare Output mode, the Output Compare (OCnx) is cleared on the Compare Match
between TCNTn and OCRnx while upcounting, and set on the Compare Match while down-
counting. In inverting Output Compare mode, the operation is inverted. The dual-slope operation
has lower maximum operation frequency than single slope operation. However, due to the sym-
metric feature of the dual-slope PWM modes, these modes are preferred for motor control
applications.
In phase correct PWM mode the counter is incremented until the counter value matches TOP.
When the counter reaches TOP, it changes the count direction. The TCNTn value will be equal
to TOP for one timer clock cycle. The timing diagram for the phase correct PWM mode is shown
on
illustrating the dual-slope operation. The diagram includes non-inverted and inverted PWM out-
puts. The small horizontal line marks on the TCNTn slopes represent Compare Matches
between OCRnx and TCNTn.
Figure 12-7. Phase Correct PWM Mode, Timing Diagram
TCNTn
OCn
OCn
Period
Figure 12-7 on page
87. The TCNTn value is in the timing diagram shown as a histogram for
1
2
OCnx
= f
clk_I/O
/2 when OCRnA is set to zero. This
3
OCnx Interrupt Flag Set
OCRnx Update
TOVn Interrupt Flag Set
(COMnx1:0 = 2)
(COMnx1:0 = 3)
87