Using Arduino with PIC32 and ATtiny Atmel Chips - Arduino - page 178

While the Atmel family of chips is compatible with Arduino, its pin-numbering scheme is different. Let's look at
the features and specifications of the ATtiny chips in Tables 9-2 , 9-3 , and 9-4 , paying particular attention to the pin
numbering, as diagrammed in Figures 9-5 , 9-6 , and 9-7 .
The Atmel family consists of the following chips:

• ATtiny 85, 45, and 25

• ATtiny 84, 44, and 24

• ATtiny 4313 and 2313

ATtiny 85/45/25
Table 9-2 shows the chip specifications for the ATtiny 85, 45, and 25.

Table 9-2. Chip Specifications for the Arduino ATtiny 85/45/25

Chip Flash EEPROM SRAM PWM ADC Digital I/O

ATtiny85 8KB 128 bytes 128 bytes 2 3 6

ATtiny45 4KB 256 bytes 256 bytes 2 3 6

ATtiny25 2KB 512 bytes 512 bytes 2 3 6

Figure 9-5. Pin layout of the ATtiny 85/45/25

Pin 7 supports I2C, and pin 5 supports SCL and SDA, as shown in Figure 9-3 . This support is maintained through
the TinyWire library. The code can be found at http://arduino.cc/playground/Code/USIi2c .

ATtiny 84/44/24
Table 9-3 shows the chip specifications for the ATtiny 84, 44, and 24.

Table 9-3. Chip Specifications for the Arduino ATtiny 84/44/24

Chip Flash EEPROM SRAM PWM ADC Digital I/O

ATtiny84 8KB 128 bytes 128 bytes 4 8 11

ATtiny44 4KB 256 bytes 256 bytes 4 8 11

ATtiny24 2KB 512 bytes 512 bytes 4 8 11