ATtiny26 Atmel Corporation, ATtiny26 Datasheet - Page 48

• Manufacturer Part Number: ATtiny26
• Manufacturer: Atmel Corporation

Specifications of ATtiny26

• Flash (kbytes): 2 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 11
• 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: No
• Crypto Engine: No
• Sram (kbytes): 0.12
• Eeprom (bytes): 128
• Self Program Memory: NO
• 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: 2
• Output Compare Channels: 3
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

MCU Control Register
– MCUCR
Alternate Functions of
Port A
48
ATtiny26(L)
The MCU Control Register contains control bits for general MCU functions.
• Bit 6 – PUD: Pull-up Disable
When this bit is set (one), the pull-ups in the I/O ports are disabled even if the DDxn and
PORTxn Registers are configured to enable the pull-ups ({DDxn, PORTxn} = 0b01). See “Con-
figuring the Pin” on page 42 for more details about this feature.
Port A has an alternate functions as analog inputs for the ADC and Analog Comparator and pin
change interrupt as shown in Table 23. If some Port A pins are configured as outputs, it is
essential that these do not switch when a conversion is in progress. This might corrupt the result
of the conversion. The ADC is described in “Analog to Digital Converter” on page 94. Analog
Comparator is described in “Analog Comparator” on page 91. Pin change interrupt triggers on
pins PA7, PA6 and PA3 if interrupt is enabled and it is not masked by the alternate functions
even if the pin is configured as an output. See details from “Pin Change Interrupt” on page 62.
Table 23. Port A Pins Alternate Functions
Table 24 and Table 25 relates the alternate functions of Port A to the overriding signals shown in
Figure 35 on page 46. Thera are changes on PA7, PA6, and PA3 digital inputs. PA3 output and
pullup driver are also overridden.
• ADC6/AIN1 Port – A, Bit 7
AIN1: Analog Comparator Negative input and ADC6: ADC input channel 6
pin as input with the internal pull-up switched off to avoid the digital port function from interfering
with the function of the analog comparator or analog to digital converter.
PCINT1: Pin Change Interrupt 1 pin. Pin change interrupt is enabled on pin when global interrupt
is enabled, pin change interrupt is enabled and the alternate function do not mask the interrupt.
The masking alternate function is the Analog Comparator. Digital input is enabled on pin PA7
also in SLEEP modes, if the pin change interrupt is enabled and not masked by the alternate
function.
• ADC5/AIN0 Port – A, Bit 6
Bit
$35 ($55)
Read/Write
Initial Value
Port Pin
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
R
7
–
0
Alternate Function
ADC6 (ADC input channel 6)
AIN1 (Analog Comparator negative input)
PCINT1 (Pin Change Interrupt 1)
ADC5 (ADC input channel 5)
AIN0 (Analog Comparator positive input)
PCINT1 (Pin Change Interrupt 1)
ADC4 (ADC input channel 4)
ADC3 (ADC input channel 3)
AREF (ADC external reference)
PCINT1 (Pin Change Interrupt 1)
ADC2 (ADC input channel 2)
ADC1 (ADC input channel 1)
ADC0 (ADC input channel 0)
PUD
R/W
6
0
R/W
SE
5
0
SM1
R/W
0
4
SM0
R/W
3
0
R
2
–
0
ISC01
R/W
1
0
ISC00
R/W
0
0
.
Configure the port
MCUCR
1477K–AVR–08/10