ATTINY26-16SI Atmel, ATTINY26-16SI Datasheet - Page 41

• Manufacturer Part Number: ATTINY26-16SI
• Description: IC AVR MCU 2K 16MHZ IND 20-SOIC
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY26-16SI

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

I/O Ports
Introduction
Ports as General
Digital I/O
1477K–AVR–08/10
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 (if configured as
input). Each output buffer, except reset, 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
Figure 31. 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 “Register Description for I/O Ports” on page 56.
Three I/O memory address locations are allocated for each port, one each for the Data Register
– PORTx, Data Direction Register – DDRx, and the Port Input Pins – PINx. The Port Input Pins
I/O location is read only, while the Data Register and the Data Direction Register are read/write.
In addition, the Pull-up Disable – PUD bit in MCUCR disables the pull-up function for all pins in
all ports when set.
Using the I/O port as General Digital I/O is described in “Ports as General Digital I/O” on page
41. 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 “Alternate Port
Functions” on page 46. Refer to the individual module sections for a full description of the alter-
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.
The ports are bi-directional I/O ports with optional internal pull-ups. Figure 32 shows a functional
description of one I/O-port pin, here generically called Pxn.
Pxn
C
pin
CC
and Ground as indicated in Figure 31.
"General Digital I/O" for
See Figure
R
Details
pu
Logic
41