ATtiny167 Atmel Corporation, ATtiny167 Datasheet - Page 126

• Manufacturer Part Number: ATtiny167
• Manufacturer: Atmel Corporation

Specifications of ATtiny167

• Flash (kbytes): 16 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 16 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: 2
• Twi (i2c): 1
• Uart: 1
• Lin: 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): 0.5
• Eeprom (bytes): 512
• 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: 3
• Input Capture Channels: 1
• Pwm Channels: 9
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

12.9.4
126
ATtiny87/ATtiny167
Phase Correct PWM Mode
Using the ICR1 Register for defining TOP works well when using fixed TOP values. By using
ICR1, the OCR1A Register is free to be used for generating a PWM output on OC1A. How-
ever, if the base PWM frequency is actively changed (by changing the TOP value), using the
OCR1A as TOP is clearly a better choice due to its double buffer feature.
In fast PWM mode, the compare units allow generation of PWM waveforms on the OC1A/B
pins. Setting the COM1x1:0 bits to two will produce a non-inverted PWM and an inverted
PWM output can be generated by setting the COM1A/B[1:0] to three (see
133). The actual OC1A/B value will only be visible on the port pin if the data direction for the
port pin is set as output (DDR_OC1A/B) and OC1A/Bi is set. The PWM waveform is generated
by setting (or clearing) the OC1A/B Register at the compare match between OCR1A/B and
TCNT1, and clearing (or setting) the OC1A/B Register at the timer clock cycle the counter is
cleared (changes from TOP to BOTTOM).
The PWM frequency for the output can be calculated by the following equation:
The N variable represents the prescaler divider (1, 8, 64, 256, or 1024).
The extreme values for the OCR1A/B Register represents special cases when generating a
PWM waveform output in the fast PWM mode. If the OCR1A/B is set equal to BOTTOM
(0x0000) the output will be a narrow spike for each TOP+1 timer clock cycle. Setting the
OCR1A/B equal to TOP will result in a constant high or low output (depending on the polarity
of the output set by the COM1A/B[1:0] bits.)
A frequency (with 50% duty cycle) waveform output in fast PWM mode can be achieved by
setting OC1A to toggle its logical level on each compare match (COM1A[1:0] = 1). The wave-
form generated will have a maximum frequency of f
zero (0x0000). This feature is similar to the OC1A toggle in CTC mode, except the double buf-
fer feature of the Output Compare unit is enabled in the fast PWM mode.
The phase correct Pulse Width Modulation or phase correct PWM mode (WGM1[3:0] = 1, 2, 3,
10, or 11) provides a high resolution phase correct PWM waveform generation option. The
phase correct PWM mode is, like the phase and frequency correct PWM mode, based on a
dual-slope operation. The counter counts repeatedly from BOTTOM (0x0000) to TOP and
then from TOP to BOTTOM. In non-inverting Compare Output mode, the Output Compare
(OC1A/B) is cleared on the compare match between TCNT1 and OCR1A/B while upcounting,
and set on the compare match while downcounting. 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 symmetric feature of the dual-slope PWM modes,
these modes are preferred for motor control applications.
The PWM resolution for the phase correct PWM mode can be fixed to 8-, 9-, or 10-bit, or
defined by either ICR1 or OCR1A. The minimum resolution allowed is 2-bit (ICR1 or OCR1A
set to 0x0003), and the maximum resolution is 16-bit (ICR1 or OCR1A set to MAX). The PWM
resolution in bits can be calculated by using the following equation:
R
PCPWM
f
OCnxPWM
=
log
---------------------------------- -
(
log
TOP
=
2 ( )
---------------------------------- -
N
+
⋅
1
(
f
)
1
clk_I/O
+
OC
TOP
1
A
= f
)
clk_I/O
/2 when OCR1A is set to
Table 12-2 on page
8265B–AVR–09/10