ATtiny261 Atmel Corporation, ATtiny261 Datasheet - Page 104

• Manufacturer Part Number: ATtiny261
• Manufacturer: Atmel Corporation

Specifications of ATtiny261

• Flash (kbytes): 2 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 4
• 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: 11
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

12.8.4
104
ATtiny261/461/861
PWM6 Mode
actual value from the port register will be visible on the port pin. The configurations of the Output
Compare Pins are described in
Table 12-4.
The PWM6 Mode (PWM1A = 1, WGM11:10 = 1X) provide PWM waveform generation option
e.g. for controlling Brushless DC (BLDC) motors. In the PWM6 Mode the OCR1A Register con-
trols all six Output Compare waveforms as the same Waveform Output (OCW1A) from the
Waform Generator is used for generating all waveforms. The PWM6 Mode also provides an Out-
put Compare Override Enable Register (OC1OE) that can be used with an instant response for
disabling or enabling the Output Compare pins. If the Output Compare Override Enable bit is
cleared, the actual value from the port register will be visible on the port pin.
The PWM6 Mode provides two counter operation modes, a single-slope operation and a dual-
slope operation. If the single-slope operation is selected (the WGM10 bit is set to 0), the counter
counts from BOTTOM to TOP (defined as OCR1C) then restart from BOTTOM like in Fast PWM
Mode. The PWM waveform is generated by setting (or clearing) the Waveforn Output (OCW1A)
at the Compare Match between OCR1A and TCNT1, and clearing (or setting) the Waveform
Output at the timer clock cycle the counter is cleared (changes from TOP to BOTTOM). The
Timer/Counter Overflow Flag (TOV1) is set each time the counter reaches the TOP and, if the
interrupt is enabled, the interrupt handler routine can be used for updating the compare value.
Whereas, if the dual-slope operation is selected (the WGM10 bit is set to 1), the counter counts
repeatedly from BOTTOM to TOP (defined as OCR1C) and then from TOP to BOTTOM like in
Phase and Frequency Correct PWM Mode. The PWM waveform is generated by setting (or
clearing) the Waveforn Output (OCW1A) at the Compare Match between OCR1A and TCNT1
when the counter increments, and clearing (or setting) the Waveform Output at the he Compare
Match between OCR1A and TCNT1 when the counter decrements. The Timer/Counter Overflow
Flag (TOV1) is set each time the counter reaches the BOTTOM and, if the interrupt is enabled,
the interrupt handler routine can be used for updating the compare value.
The timing diagram for the PWM6 Mode in single-slope operation when the COM1A1:0 bits are
set to “10” is shown in
the TOP value. The counter is then cleared at the following timer clock cycle. The TCNT1 value
is in the timing diagram shown as a histogram for illustrating the single-slope operation. The tim-
ing diagram includes Output Compare pins OC1A and OC1A, and the corresponding Output
Compare Override Enable bits (OC1OE1:OC1OE0).
COM1x1
0
0
1
1
Output Compare pin configurations in Phase and Frequency Correct PWM Mode
COM1x0
0
1
0
1
Figure
12-14. The counter is incremented until the counter value matches
Table
OC1x Pin
Disconnected
OC1x
Disconnected
Disconnected
12-4.
OC1x Pin
Disconnected
OC1x
OC1x
OC1x
2588E–AVR–08/10