ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 106

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• 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: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

13.8.3
13.8.4
13.8.5
13.8.6
7766F–AVR–11/10
Timer/Counter Register – TCNT0
Output Compare Register A – OCR0A
Output Compare Register B – OCR0B
Timer/Counter Interrupt Mask Register – TIMSK0
Table 13-9.
If external pin modes are used for the Timer/Counter0, transitions on the T0 pin will clock the
counter even if the pin is configured as an output. This feature allows software control of the
counting.
The Timer/Counter Register gives direct access, both for read and write operations, to the
Timer/Counter unit 8-bit counter. Writing to the TCNT0 Register blocks (removes) the Compare
Match on the following timer clock. Modifying the counter (TCNT0) while the counter is running,
introduces a risk of missing a Compare Match between TCNT0 and the OCR0x Registers.
The Output Compare Register A contains an 8-bit value that is continuously compared with the
counter value (TCNT0). A match can be used to generate an Output Compare interrupt, or to
generate a waveform output on the OC0A pin.
The Output Compare Register B contains an 8-bit value that is continuously compared with the
counter value (TCNT0). A match can be used to generate an Output Compare interrupt, or to
generate a waveform output on the OC0B pin.
• Bits 7..3, 0 – Res: Reserved Bits
These bits are reserved bits and will always read as zero.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
CS02
1
1
1
1
CS01
0
0
1
1
7
TCNT0[7:0]
R/W
0
7
R/W
0
7
R/W
0
7
–
R
0
Clock Select Bit Description (Continued)
CS00
0
1
0
1
6
R/W
0
6
R/W
0
6
R/W
0
6
–
R
0
Description
clk
clk
External clock source on T0 pin. Clock on falling edge.
External clock source on T0 pin. Clock on rising edge.
I/O
I/O
5
R/W
0
5
R/W
0
5
R/W
0
5
–
R
0
/256 (From prescaler)
/1024 (From prescaler)
4
R/W
0
4
R/W
0
4
R/W
0
4
–
R
0
OCR0A[7:0]
OCR0B[7:0]
3
0
3
0
3
0
3
–
R
0
R/W
R/W
R/W
2
R/W
0
2
R/W
0
2
R/W
0
2
OCIE0B
R/W
0
1
R/W
0
1
R/W
0
1
R/W
0
1
OCIE0A
R/W
0
ATmega16/32U4
0
R/W
0
0
R/W
0
0
R/W
0
0
TOIE0
R/W
0
TCNT0
OCR0A
OCR0B
TIMSK0
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