Timer/Counter 1
Review each signal assignment and the peripheral enable conditions in the data sheet. T → PD5 · ICP → PB0 · OCA → PB1 · OCB → PB3
ATtiny88 pinout
Package pin assignments for ATtiny88, with peripheral signals, clock grades and a serial programming guide.
QFN-28 29 contacts
PDIP-28 28 contacts
TQFP-32 32 contacts
UFBGA-32 32 contacts
QFN-32
33 contacts Current package8 KiB flash · 512 B SRAM · 64 B EEPROM. Choose the marked order code for voltage, clock, and temperature.
QFN-32 pinout
EP is the exposed center pad on the underside.
27 · PC4
General-purpose digital I/O. Alternate assignments: SDA (TWI), ADC4 (ADC), PCINT12 (EXINT).
After reset · GPIO driver is high impedance during reset. Clock, debug, and alternate-function use depend on fuse and peripheral configuration.
All 33 pins
| Pin | Signal | Direction | Function |
|---|---|---|---|
| 1 | PD3 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT19 (EXINT), INT1 (EXINT). |
| 2 | PD4 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT20 (EXINT), T (TC0). |
| 3 | PA2 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT26 (EXINT). |
| 4 | VCC Supply | Supply | Digital supply. Connect every VCC pin and place a local 100 nF ceramic bypass close to each VCC-to-ground pair. |
| 5 | GND Return | Return | Supply return. Connect every ground pin. |
| 6 | PA3 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT27 (EXINT). |
| 7 | PB6 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT6 (EXINT). |
| 8 | PB7 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT7 (EXINT). |
| 9 | PD5 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: T (TC1), PCINT21 (EXINT). |
| 10 | PD6 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: AIN0 (AC), PCINT22 (EXINT). |
| 11 | PD7 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: AIN1 (AC), PCINT23 (EXINT). |
| 12 | PB0 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: ICP (TC1), PCINT0 (EXINT). |
| 13 | PB1 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: OCA (TC1), PCINT1 (EXINT). |
| 14 | PB2 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: SS (SPI), PCINT2 (EXINT). |
| 15 | PB3 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: OCB (TC1), MOSI (SPI), PCINT3 (EXINT). |
| 16 | PB4 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: MISO (SPI), PCINT4 (EXINT). |
| 17 | PB5 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: SCK (SPI), PCINT5 (EXINT). |
| 18 | AVCC Supply | Supply | Analog supply. Connect it to the supply even if analog conversion is unused. Follow the data sheet’s filtering guidance for precision conversion. |
| 19 | PA0 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: ADC6 (ADC), PCINT24 (EXINT). |
| 20 | PC7 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT15 (EXINT). |
| 21 | GND Return | Return | Supply return. Connect every ground pin. |
| 22 | PA1 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: ADC7 (ADC), PCINT25 (EXINT). |
| 23 | PC0 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: ADC0 (ADC), PCINT8 (EXINT). |
| 24 | PC1 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: ADC1 (ADC), PCINT9 (EXINT). |
| 25 | PC2 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: ADC2 (ADC), PCINT10 (EXINT). |
| 26 | PC3 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: ADC3 (ADC), PCINT11 (EXINT). |
| 27 | PC4 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: SDA (TWI), ADC4 (ADC), PCINT12 (EXINT). |
| 28 | PC5 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: SCL (TWI), ADC5 (ADC), PCINT13 (EXINT). |
| 29 | PC6 Input / I/O | Input / I/O | Active-low reset input by default. Use as GPIO only where the reset-disable fuse is supported and configured. Alternate assignments: PCINT14 (EXINT). |
| 30 | PD0 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT16 (EXINT). |
| 31 | PD1 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT17 (EXINT). |
| 32 | PD2 Bidirectional | Bidirectional | General-purpose digital I/O. Alternate assignments: PCINT18 (EXINT), INT0 (EXINT). |
| EP | EP Ground pad | Ground pad | Solder the exposed center pad to ground as shown in the package pinout notes. Connect the numbered ground contacts too. |
Signal assignments
Analog comparator
Review each signal assignment and the peripheral enable conditions in the data sheet. AIN0 → PD6 · AIN1 → PD7
SPI peripheral
Use SCK, MOSI, MISO and a chip-select line. Firmware selects direction and clock phase. Check the separate ISP mapping when programming. SCK → PB5 · MISO → PB4 · MOSI → PB3 · SS → PB2
TWI / I²C
Connect SDA and SCL to the bus with pull-ups to a voltage supported by all devices. Verify the pull-up value for the bus capacitance and rate. SCL → PC5 · SDA → PC4
Analog-to-digital converter
Select the analog channel and reference in firmware. The reference choice and supply constrain the input range. ADC0 → PC0 · ADC1 → PC1 · ADC2 → PC2 · ADC3 → PC3 · ADC4 → PC4 · ADC5 → PC5 · ADC6 → PA0 · ADC7 → PA1
External interrupts
Review each signal assignment and the peripheral enable conditions in the data sheet. PCINT0 → PB0 · PCINT1 → PB1 · PCINT2 → PB2 · PCINT3 → PB3 · PCINT4 → PB4 · PCINT5 → PB5 · PCINT6 → PB6 · PCINT7 → PB7 · PCINT8 → PC0 · PCINT9 → PC1 · PCINT10 → PC2 · PCINT11 → PC3 · PCINT12 → PC4 · PCINT13 → PC5 · PCINT14 → PC6 · PCINT15 → PC7 · PCINT16 → PD0 · PCINT17 → PD1 · PCINT18 → PD2 · PCINT19 → PD3 · PCINT20 → PD4 · PCINT21 → PD5 · PCINT22 → PD6 · PCINT23 → PD7 · PCINT24 → PA0 · PCINT25 → PA1 · PCINT26 → PA2 · PCINT27 → PA3 · INT0 → PD2 · INT1 → PD3
Timer/Counter 0
Review each signal assignment and the peripheral enable conditions in the data sheet. T → PD4
Electrical limits
| Parameter | Limit | Conditions and source |
|---|---|---|
| Program flash8 KiB | 8 KiB | Nonvolatile program memory. 8008H · Memory |
| SRAM512 B | 512 B | Volatile data and stack storage. 8008H · Memory |
| EEPROM64 B | 64 B | Nonvolatile data storage. 8008H · Memory |
| Clock and supplyOrder-code dependent | Order-code dependent | Use the grade table and the device’s speed-versus-voltage curve. 8008H · Electrical Characteristics |
Models and documents
Each package lists the documented order codes and variants covered by this map. Select the marked model to see its peripheral assignments and memory. Check the exact order code and datasheet revision before laying out a PCB.
- ATtiny88
- 8 KiB flash · 512 B SRAM · 64 B EEPROM. Choose the marked order code for voltage, clock, and temperature.
- ATtiny88-MU
- 8 KiB flash · 512 B SRAM · 64 B EEPROM · 1.8–5.5 V · 12 MHz maximum · -40 to +85 °C
- ATtiny88-MUR
- 8 KiB flash · 512 B SRAM · 64 B EEPROM · 1.8–5.5 V · 12 MHz maximum · -40 to +85 °C
- ATtiny88 data sheet· 8008H · Pin configuration, electrical characteristics, ordering table and serial programming.
- ATtiny_DFP Device Family Pack· Machine-readable device definition: package contacts, peripheral routes, and memory sizes.
- AVR Microcontroller Hardware Design Considerations· Power supply, reset network, and programmer connection guidance.
- ATtiny88 documentation and errata· Check current manufacturer documentation, ordering status and silicon revision applicability.
- AVR source register· Source identifiers, applicability, retrieval dates, and SHA-256 digests.