ATtiny20 Atmel Corporation, ATtiny20 Datasheet - Page 44

• Manufacturer Part Number: ATtiny20
• Manufacturer: Atmel Corporation

Specifications of ATtiny20

• Flash (kbytes): 2 Kbytes
• Pin Count: 14
• Max. Operating Frequency: 12 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 5
• Hardware Qtouch Acquisition: Yes
• Max I/o Pins: 12
• Ext Interrupts: 12
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Twi (i2c): 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: Yes
• Crypto Engine: No
• Sram (kbytes): 0.12
• Self Program Memory: NO
• 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: 2
• Output Compare Channels: 4
• Input Capture Channels: 1
• Pwm Channels: 3
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

10. I/O Ports
10.1
44
Overview
ATtiny20
All AVR ports have true Read-Modify-Write functionality when used as general digital I/O ports.
This means that the direction of one port pin can be changed without unintentionally changing
the direction of any other pin with the SBI and CBI instructions. The same applies when chang-
ing drive value (if configured as output) or enabling/disabling of pull-up resistors. Each output
buffer has symmetrical drive characteristics with both high sink and source capability. The pin
driver is strong enough to drive LED displays directly. All port pins have individually selectable
pull-up resistors with a supply-voltage invariant resistance. All I/O pins have protection diodes to
both V
page 172
Figure 10-1. I/O Pin Equivalent Schematic
All registers and bit references in this section are written in general form. A lower case “x” repre-
sents the numbering letter for the port, and a lower case “n” represents the bit number. However,
when using the register or bit defines in a program, the precise form must be used. For example,
PORTB3 for bit no. 3 in Port B, here documented generally as PORTxn. The physical I/O Regis-
ters and bit locations are listed in
Four I/O memory address locations are allocated for each port, one each for the Data Register –
PORTx, Data Direction Register – DDRx, Pull-up Enable Register – PUEx, and the Port Input
Pins – PINx. The Port Input Pins I/O location is read only, while the Data Register, the Data
Direction Register, and the Pull-up Enable Register are read/write. However, writing a logic one
to a bit in the PINx Register, will result in a toggle in the corresponding bit in the Data Register.
Using the I/O port as General Digital I/O is described in
45. Most port pins are multiplexed with alternate functions for the peripheral features on the
device. How each alternate function interferes with the port pin is described in
Functions” on page
nate functions.
Note that enabling the alternate function of some of the port pins does not affect the use of the
other pins in the port as general digital I/O.
CC
and Ground as indicated in
for a complete list of parameters.
Pxn
49. Refer to the individual module sections for a full description of the alter-
“Register Description” on page
C
pin
Figure 10-1 on page
“Ports as General Digital I/O” on page
44. See
"General Digital I/O" for
58.
See Figure
R
“Electrical Characteristics” on
Details
pu
Logic
“Alternate Port
8235B–AVR–04/11