ATmega325A Atmel Corporation, ATmega325A Datasheet - Page 130

• Manufacturer Part Number: ATmega325A
• Manufacturer: Atmel Corporation

Specifications of ATmega325A

• Flash (kbytes): 32 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 17
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• 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: 3
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

16.11 Register Description
16.11.1
8285D–AVR–06/11
TCCR1A – Timer/Counter1 Control Register A
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P
• Bit 7:6 – COM1A[1:0]: Compare Output Mode for Unit A
• Bit 5:4 – COM1B[1:0]: Compare Output Mode for Unit B
The COM1A[1:0] and COM1B[1:0] control the Output Compare pins (OC1A and OC1B respec-
tively) behavior. If one or both of the COM1A[1:0] bits are written to one, the OC1A output
overrides the normal port functionality of the I/O pin it is connected to. If one or both of the
COM1B[1:0] bit are written to one, the OC1B output overrides the normal port functionality of the
I/O pin it is connected to. However, note that the Data Direction Register (DDR) bit correspond-
ing to the OC1A or OC1B pin must be set in order to enable the output driver.
When the OC1A or OC1B is connected to the pin, the function of the COM1x[1:0] bits is depen-
dent of the WGM1[3:0] bits setting...
WGM1[3:0] bits are set to a Normal or a CTC mode (non-PWM).
Table 16-2.
Table 16-3
PWM mode.
Table 16-3.
Note:
Bit
(0x80)
Read/Write
Initial Value
COM1A1/COM1B1
COM1A1/COM1B1
1. A special case occurs when OCR1A/OCR1B equals TOP and COM1A1/COM1B1 is set. In
0
0
1
1
0
0
1
1
this case the compare match is ignored, but the set or clear is done at TOP.
Mode” on page 122.
shows the COM1x[1:0] bit functionality when the WGM1[3:0] bits are set to the fast
COM1A1
Compare Output Mode, non-PWM
Compare Output Mode, Fast PWM
R/W
7
0
COM1A0
COM1A0/COM1B0
COM1A0/COM1B0
R/W
6
0
for more details.
0
1
0
1
0
1
0
1
COM1B1
R/W
5
0
Table 16-2
COM1B0
R/W
4
0
Normal port operation, OC1A/OC1B disconnected.
Toggle OC1A/OC1B on Compare Match.
Clear OC1A/OC1B on Compare Match (Set output to
low level).
Set OC1A/OC1B on Compare Match (Set output to
high level).
Normal port operation, OC1A/OC1B disconnected.
WGM1[3:0] = 14 or 15: Toggle OC1A on Compare
Match, OC1B disconnected (normal port operation).
For all other WGM1 settings, normal port operation,
OC1A/OC1B disconnected.
Clear OC1A/OC1B on Compare Match, set
OC1A/OC1B at BOTTOM (non-inverting mode)
Set OC1A/OC1B on Compare Match, clear
OC1A/OC1B at BOTTOM (inverting mode)
Description
Description
shows the COM1x[1:0] bit functionality when the
(1)
R
3
–
0
R
2
–
0
WGM11
R/W
1
0
WGM10
See ”Fast PWM
R/W
0
0
TCCR1A
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