ATtiny167 Atmel Corporation, ATtiny167 Datasheet - Page 124

• 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

12.9.3
124
ATtiny87/ATtiny167
Fast PWM Mode
An interrupt can be generated at each time the counter value reaches the TOP value by either
using the OCF1A or ICF1 flag according to the register used to define the TOP value. If the
interrupt is enabled, the interrupt handler routine can be used for updating the TOP value.
However, changing the TOP to a value close to BOTTOM when the counter is running with
none or a low prescaler value must be done with care since the CTC mode does not have the
double buffering feature. If the new value written to OCR1A or ICR1 is lower than the current
value of TCNT1, the counter will miss the compare match. The counter will then have to count
to its maximum value (0xFFFF) and wrap around starting at 0x0000 before the compare match
can occur. In many cases this feature is not desirable. An alternative will then be to use the
fast PWM mode using OCR1A for defining TOP (WGM1[3:0] = 15) since the OCR1A then will
be double buffered.
For generating a waveform output in CTC mode, the OC1A output can be set to toggle its log-
ical level on each compare match by setting the Compare Output mode bits to toggle mode
(COM1A[1:0] = 1). The OC1A value will not be visible on the port pin unless the data direction
for the pin is set to output (DDR_OC1A = 1) and OC1Ai is set. The waveform generated will
have a maximum frequency of f
waveform frequency is defined by the following equation:
The N variable represents the prescaler factor (1, 8, 64, 256, or 1024).
As for the Normal mode of operation, the TOV1 flag is set in the same timer clock cycle that
the counter counts from MAX to 0x0000.
The fast Pulse Width Modulation or fast PWM mode (WGM1[3:0] = 5, 6, 7, 14, or 15) provides
a high frequency PWM waveform generation option. The fast PWM differs from the other
PWM options by its single-slope operation. The counter counts from BOTTOM to TOP then
restarts from BOTTOM. In non-inverting Compare Output mode, the Output Compare
(OC1A/B) is set on the compare match between TCNT1 and OCR1A/B, and cleared at TOP.
In inverting Compare Output mode output is cleared on compare match and set at TOP. Due
to the single-slope operation, the operating frequency of the fast PWM mode can be twice as
high as the phase correct and phase and frequency correct PWM modes that use dual-slope
operation. This high frequency makes the fast PWM mode well suited for power regulation,
rectification, and DAC applications. High frequency allows physically small sized external
components (coils, capacitors), hence reduces total system cost.
The PWM resolution for fast PWM 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:
f
OCnA
R
FPWM
=
OC
-------------------------------------------------- -
2 N
=
1
⋅
A
log
---------------------------------- -
= f
⋅
(
f
1
clk_I/O
(
log
clk_I/O
TOP
+
2 ( )
OCRnA
/2 when OCR1A is set to zero (0x0000). The
+
1
)
)
8265B–AVR–09/10