ATMEGA88-20PI - 8KB Flash 20MHz AVR MCU 28-DIP | Microchip
MPN: ATMEGA88-20PI ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.65 | $26.50 |
| 100 | $2.28 | $228.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.85 | $1,850.00 |
ATMEGA88-20PI Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor that executes most of its 131 instructions in a single clock cycle, sitting within the power-management-and-embedded-control hierarchy between simple 8051-class MCUs and 32-bit ARM Cortex-M devices. AVR MCUs remain a staple of embedded control, hobby electronics (the Arduino Uno is built on the closely related ATmega328P), and cost-sensitive industrial products.
Key features include 23 general-purpose I/O lines, three flexible timer/counters with compare and PWM modes, an 8-channel 10-bit ADC, byte-oriented Two-Wire (I2C) interface, SPI, and a serial programmable USART. Peripherals include brown-out detection/reset, power-on reset, watchdog timer, and debugWIRE on-chip debugging through the reset pin.
The ATmega88 self-programming Flash supports read-while-write operation for in-system firmware updates, and the picoPower technology family provides multiple sleep modes for low-power designs. Operating voltage spans 1.8V to 5.5V (the 20MHz speed grade requires 4.5V to 5.5V for full-speed operation).
Typical applications include industrial sensor nodes, motor and LED control, HVAC controllers, battery-powered instruments, and education/embedded prototypes where through-hole DIP mounting simplifies assembly and socket-based rework.
Design consideration: when running at 20MHz, keep the supply at 5V within the 4.5V-5.5V band and place 100nF decoupling on VCC/AVCC with AREF decoupled separately.
This page adds distributor-sourced alternatives, pinout, design notes, and pricing context beyond what the manufacturer datasheet provides.
Drop-in alternatives for ATMEGA88-20PI — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ATMEGA88-20PI (same form factor and footprint) — differing in Timers, Package, ADC, EEPROM, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA88-20PU
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →ATMEGA8-16PI
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →ATMEGA48V-10PU
✅ Drop-In✓ In Stock
$0.89 / Unit
View Datasheet →ATMEGA88-20MU
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →ATMEGA328P-PU
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →ATMEGA88-20PI Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-bit |
| Max Clock Speed | 20 MHz |
| Program Memory Size | 8 KB (4K x 16) FLASH |
| Program Memory Type | FLASH (ISP, self-programming, read-while-write) |
| SRAM Size | 1 KB |
| EEPROM Size | 512 B |
| Operating Voltage Range | 1.8 V to 5.5 V |
| Connectivity | I2C, SPI, UART/USART |
| Peripherals | Brown-out Detect/Reset, POR, PWM, WDT |
| Number of I/O | 23 |
| ADC | 8-channel, 10-bit |
| Timers | 3 timer/counters with compare and PWM modes |
| Instructions | 131 instructions, most single-cycle |
| Throughput | Up to 20 MIPS at 20 MHz |
| On-Chip Debug | debugWIRE |
| Operating Temperature | -40C to +85C (industrial) |
| Package | 28-PDIP (0.300 in, 7.62 mm) |
| Mounting Type | Through Hole |
| Part Status | Obsolete |
ATMEGA88-20PI Pin Configuration
| Pin 1 | PC6 (RESET) — Reset input; also debugWIRE interface |
| Pin 2 | PD0 (RXD) — Port D bit 0 / USART receive |
| Pin 3 | PD1 (TXD) — Port D bit 1 / USART transmit |
| Pin 4 | PD2 (INT0) — Port D bit 2 / external interrupt 0 |
| Pin 5 | PD3 (INT1/OC2B) — Port D bit 3 / external interrupt 1 / Timer2 PWM output B |
| Pin 6 | PD4 (T0/XCK) — Port D bit 4 / Timer0 clock input / USART external clock |
| Pin 7 | VCC — Digital supply voltage (1.8V to 5.5V) |
| Pin 8 | GND — Ground |
| Pin 9 | PB6 (XTAL1/TOSC1) — Crystal oscillator input / Timer2 oscillator input |
| Pin 10 | PB7 (XTAL2/TOSC2) — Crystal oscillator output / Timer2 oscillator output |
| Pin 11 | PD5 (T1/OC0B) — Port D bit 5 / Timer1 clock input / Timer0 PWM output B |
| Pin 12 | PD6 (AIN0/OC0A) — Port D bit 6 / analog comparator positive input / Timer0 PWM output A |
| Pin 13 | PD7 (AIN1) — Port D bit 7 / analog comparator negative input |
| Pin 14 | PB0 (ICP1/CLKO) — Port B bit 0 / Timer1 input capture / system clock output |
| Pin 15 | PB1 (OC1A) — Port B bit 1 / Timer1 PWM output A |
| Pin 16 | PB2 (SS/OC1B) — Port B bit 2 / SPI slave select / Timer1 PWM output B |
| Pin 17 | PB3 (MOSI/OC2A) — SPI master output / Timer2 PWM output A |
| Pin 18 | PB4 (MISO) — SPI master input |
| Pin 19 | PB5 (SCK) — SPI serial clock |
| Pin 20 | AVCC — ADC supply voltage (connect to VCC through low-pass filter) |
| Pin 21 | AREF — ADC analog reference; decouple to GND with 100nF |
| Pin 22 | GND — Ground |
| Pin 23 | PC0 (ADC0) — Port C bit 0 / ADC channel 0 |
| Pin 24 | PC1 (ADC1) — Port C bit 1 / ADC channel 1 |
| Pin 25 | PC2 (ADC2) — Port C bit 2 / ADC channel 2 |
| Pin 26 | PC3 (ADC3) — Port C bit 3 / ADC channel 3 |
| Pin 27 | PC4 (ADC4/SDA) — ADC channel 4 / Two-Wire (I2C) data |
| Pin 28 | PC5 (ADC5/SCL) — ADC channel 5 / Two-Wire (I2C) clock |
Typical Applications
ATMEGA88-20PI is suitable for 6 applications: Industrial Sensor Nodes, Education and Embedded Prototyping, Motor and LED Control, HVAC and Appliance Controllers, Battery-Powered Instruments, Serial Communication Bridges.
Industrial Sensor Nodes
The ATMEGA88-20PI fits industrial sensor acquisition nodes where an 8-channel 10-bit ADC sampling thermistors, pressure bridges, or potentiometers at moderate rates is sufficient, and the -40C to +85C industrial temperature range covers unconditioned factory environments. The AVR core at 20MHz executes filtering (moving average, simple IIR) and scaling in C with margin to spare, while 512B EEPROM stores calibration constants that survive power loss. The USART links to RS-485 transceivers or wireless modules, and the brown-out detector plus watchdog timer guarantee watchdog-recoverable firmware behavior in unattended installations. Running from a 5V industrial rail at 20MHz, a typical node draws a few milliamps, and sleep modes between samples extend battery-backed operation. Because the part is in through-hole DIP, prototype revisions and field firmware updates via ISP bootloader are straightforward.
Recommended
Education and Embedded Prototyping
The 28-pin PDIP ATmega88 is a classic teaching and prototyping MCU: the through-hole package plugs into solderless breadboards and ZIF sockets, making wiring errors easy to correct. With 131 mostly single-cycle AVR instructions, students learn real RISC assembly, while AVR-GCC and Microchip Studio provide free C toolchains. debugWIRE allows single-step debugging through the single reset pin with only an ISP mkII-class tool - no JTAG required. The 8KB Flash accommodates full course projects (keypads, LCD drivers, PWM motor demos using the three timers), and the 8-channel 10-bit ADC supports analog lab exercises. Because code written for ATmega88 ports almost unchanged to ATmega328P (the Arduino Uno core), coursework transitions directly to industry-relevant hardware. Universities and maker labs commonly keep DIP-28 AVR stock precisely for this socketability.
Recommended
Motor and LED Control
Three timer/counters with compare and PWM outputs make the ATMEGA88-20PI well suited to DC motor speed control, servo driving, and LED dimming. At 20MHz, 8-bit PWM reaches 78 kHz - above audible noise for fans and pumps - while 16-bit Timer1 handles precise servo pulse timing or encoder counting. The watchdog and brown-out reset ensure the MCU recovers safely from brownouts on inductively noisy motor rails, and the 10-bit ADC reads back current shunts or potentiometer setpoints. 23 GPIO lines drive H-bridge direction logic and status LEDs without glue logic. In a 5V DIP implementation, driving a MOSFET gate directly through a series resistor is acceptable for switching at 20kHz rates; optocoupler isolation is recommended when the power stage sits on a different ground domain.
Recommended
HVAC and Appliance Controllers
White goods and HVAC boards benefit from the ATMEGA88-20PI combination of an industrial temperature rating, 23 GPIO for relays, buttons, and displays, and self-programming Flash enabling field firmware updates over UART. The 10-bit ADC multiplexes NTC thermistor inputs for zone and coil temperature measurement, while EEPROM retains user setpoints and cycle counters across power cycles. The byte-oriented Two-Wire (I2C) interface drives RTC chips and segment LCD controllers, and the USART connects to display modules or building-management buses. Brown-out detection at a configured threshold prevents EEPROM corruption during mains sags, and the watchdog restarts hung control loops - both critical for unattended appliances. DIP packaging supports low-volume contract manufacturing without reflow equipment.
Recommended
Battery-Powered Instruments
With multiple picoPower sleep modes, the ATMEGA88-20PI suits portable measurement instruments such as handheld meters, data loggers, and test probes. Power-down mode reduces consumption to the microamp level between measurements; Timer2 with asynchronous 32.768 kHz crystal keeps a real-time counter running in sleep. A single 4.5V-5.5V rail at reduced clock, or 3V operation at up to ~10MHz via the L-derating curve, allows direct NiMH or lithium cell supply without a regulator in simple designs. The ADC with internal reference digitizes battery voltage for fuel-gauging, and EEPROM logs calibration and event counts. Interrupt-on-pin-change on all ports wakes the device on button press without polling. End-of-life status means new battery-product designs should start on ATmega328P, but existing instrument firmware on ATmega88 continues to be serviceable with channel stock.
Recommended
Serial Communication Bridges
The ATMEGA88-20PI includes USART, SPI, and I2C (Two-Wire) simultaneously, making it an effective protocol translator or bridge in legacy equipment. Typical roles include UART-to-I2C command interpreters, SPI flash or sensor front-ends presenting a simple ASCII UART interface, and RS-232 debugging taps for production-line fixtures. At 20MHz the USART runs comfortably at 115200 baud with interrupt-driven buffering in the 1KB SRAM. The SPI hardware handles clock rates up to fosc/2 (10MHz), sufficient for display controllers and high-speed ADC front-ends. Because it is a DIP part, engineers can drop the MCU into existing test-jig sockets during fixture refurbishment. For new bridges, the pin-compatible ATmega328P with doubled SRAM allows larger buffers and more robust protocol stacks.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA88-20PI — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA88-20PU | ATMEGA8-16PI | ATMEGA48V-10PU | ATMEGA328P-PU |
|---|---|---|---|---|---|
| Package | 28-PDIP (0.300 in, 7.62 mm) | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 8 KB | 8 KB | 8 KB | 4 KB | 32 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 512 B | 2 KB |
| EEPROM | 512 B | 512 B | 512 B | 256 B | 1 KB |
| Max Clock Speed | 20 MHz | 20 MHz | 16 MHz | 10 MHz | 20 MHz |
| Operating Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 4.5 V to 5.5 V (16MHz grade) | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| On-Chip Debug | debugWIRE | debugWIRE | None | debugWIRE | debugWIRE |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Active |
Key Differentiators
- 20MHz performance with debugWIRE (vs ATMEGA8-16PI)
- Full memory capacity in same footprint (vs ATMEGA48V-10PU)
- Lower cost than successor for legacy repairs (vs ATMEGA328P-PU)
Design Notes
Supply the ATMEGA88-20PI at 4.5V-5.5V when using the full 20MHz clock; the datasheet Safe Operating Area derates maximum frequency below 4.5V (roughly 16MHz at 4.5V, 10MHz at 2.7V). Decouple VCC and AVCC each with 100nF ceramic capacitors placed within 5mm of the pins, and connect AVCC to VCC through an LC or RC low-pass filter when the ADC must reject digital noise. Tie AREF to GND via 100nF; do not drive AREF while the internal reference is selected or the ADC may be damaged.
For DIP prototypes on breadboards, keep the crystal within 20mm of XTAL1/XTAL2 (pins 9-10) with load capacitors matched to the crystal spec (typically 22pF for 8-20MHz crystals). Route the RESET line (pin 1) with a 10k pull-up; long uncommitted reset traces pick up noise and cause spurious resets, especially with motor loads on the same board. Star-ground the analog section: bring AGND (pin 22) and DGND (pin 8) together at one point near the supply return.
Fuse misconfiguration is the most common ATmega88 failure mode: selecting external crystal while the chip has none locks out further ISP programming (clock-source lockout); recover with a slow external clock injected on XTAL1. DebugWIRE shares the RESET pin - once DWEN fuse is set, ISP is disabled until debugWIRE is disabled in the debugger. Also, since the part is discontinued, buy only from traceable distributors and qualify ATMEGA328P-PU for new designs to avoid supply cliffs.
Compliance Information
PI suffix denotes lead-free (RoHS) industrial-temperature DIP packaging per Microchip/Atmel part numbering. REACH, halogen-free, and conflict-minerals declarations should be requested via Microchip compliance documentation.
