ATtiny461 Automotive Atmel Corporation, ATtiny461 Automotive Datasheet - Page 103

• Manufacturer Part Number: ATtiny461 Automotive
• Manufacturer: Atmel Corporation

Specifications of ATtiny461 Automotive

• Flash (kbytes): 4 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: 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): 0.25
• Eeprom (bytes): 256
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 150
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 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

16.7.2
7753F–AVR–01/11
Fast
PWM Mode
The Timer/Counter Overflow Flag (TOV1) is set in the same clock cycle as the TCNT1 becomes
zero. The TOV1 Flag in this case behaves like a 11th bit, except that it is only set, not cleared.
However, combined with the timer overflow interrupt, that automatically clears the TOV1 Flag,
the timer resolution can be increased by software. There are no special cases to consider in the
Normal mode, a new counter value can be written anytime.
The Output Compare Unit can be used to generate interrupts at some given time. Using the Out-
put Compare to generate waveforms in Normal mode is not recommended, since this will
occupy too much of the CPU time. For generating a waveform, the OCW1x output can be set to
toggle its logical level on each Compare Match by setting the Compare Output mode bits to tog-
gle mode (COM1x1:0 = 1). The OC1x value will not be visible on the port pin unless the data
direction for the pin is set to output. The waveform generated will have a maximum frequency of
f
equation:
Resolution shows how many bit is required to express the value in the OCR1C register. It is cal-
culated by following equation:
The Output Compare Pin configurations in Normal Mode are described in
Table 16-2.
The fast Pulse Width Modulation or fast PWM mode (PWM1x = 1 and WGM10 = 0) provides a
high frequency PWM waveform generation option. The fast PWM differs from the other PWM
option by its single-slope operation. The counter counts from BOTTOM to TOP (defined as
OCR1C) then restarts from BOTTOM. In non-inverting Compare Output mode the Waveform
Output (OCW1x) is cleared on the Compare Match between TCNT1 and OCR1x and set at
BOTTOM. In inverting Compare Output mode, the Waveform Output is set on Compare Match
and cleared at BOTTOM. In complementary Compare Output mode the Waveform Output is
cleared on the Compare Match and set at BOTTOM.
Due to the single-slope operation, the operating frequency of the fast PWM mode can be twice
as high as the Phase and Frequency Correct PWM mode 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), and therefore reduces total system cost.
The timing diagram for the fast PWM mode is shown in
mented until the counter value matches 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.
OC1x
COM1x1
0
0
1
1
= f
clkT1
/4 when OCR1C is set to zero. The waveform frequency is defined by the following
Output Compare Pin Configurations in Normal Mode
COM1x0
0
1
0
1
Resolution
f
ATtiny261/ATtiny461/ATtiny861
OC1x
OC1x Pin
Disconnected
Disconnected
Disconnected
Disconnected
PWM
=
---------------------------------------------
2
= log
1
f
clkT1
+
2
(OCR1C + 1).
OCR1C
Figure
16-11. The counter is incre-
Disconnected
OC1x
OC1x
OC1x
OC1x Pin
Table
16-2.
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