ATtiny43U Atmel Corporation, ATtiny43U Datasheet - Page 94

• Manufacturer Part Number: ATtiny43U
• Manufacturer: Atmel Corporation

Specifications of ATtiny43U

• Flash (kbytes): 4 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 8 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: 4
• 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): 64
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 0.7 to 5.5
• Operating Voltage (vcc): 0.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 4
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

12.9.5
94
ATtiny43U
TCNT0 – Timer/Counter Register
However, for ensuring compatibility with future devices, this bit must be set to zero when
TCCR0B is written when operating in PWM mode. When writing a logical one to the FOCnB bit,
an immediate Compare Match is forced on the Waveform Generation unit. The OCnB output is
changed according to its COMnB1:0 bits setting. Note that the FOCnB bit is implemented as a
strobe. Therefore it is the value present in the COMnB1:0 bits that determines the effect of the
forced compare.
A FOCnB strobe will not generate any interrupt, nor will it clear the timer in CTC mode using
OCRnB as TOP.
The FOCnB bit is always read as zero.
• Bits 5, 4 – Res: Reserved Bits
These bits are reserved and will always read zero.
• Bit 3 – WGMn2: Waveform Generation Mode
See the description in the
• Bits 2:0 – CSn[2:0]: Clock Select
The three Clock Select bits select the clock source to be used by the Timer/Counter.
Table 12-9.
If external pin modes are used for the Timer/Countern, transitions on the Tn pin will clock the
counter even if the pin is configured as an output. This feature allows software control of the
counting.
Bit
0x32 (0x52)
Read/Write
Initial Value
CSn2
0
0
0
0
1
1
1
1
CSn1
0
0
1
1
0
0
1
1
Clock Select Bit Description
R/W
7
0
CSn0
0
1
0
1
0
1
0
1
R/W
“Register Description” on page
6
0
Description
No clock source (Timer/Counter stopped)
clk
clk
clk
clk
clk
External clock source on Tn pin. Clock on falling edge.
External clock source on Tn pin. Clock on rising edge.
I/O
I/O
I/O
I/O
I/O
/(No prescaling)
/8 (From prescaler)
/64 (From prescaler)
/256 (From prescaler)
/1024 (From prescaler)
R/W
5
0
R/W
4
0
TCNT0[7:0]
R/W
3
0
90.
R/W
2
0
R/W
1
0
R/W
0
0
8048B–AVR–03/09
TCNT0