ATMEGA8A-PU - 8-bit AVR MCU 16MHz 8KB Flash DIP-28 | Microchip
MPN: ATMEGA8A-PU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.95 | $2.95 |
| 10 | $2.66 | $26.60 |
| 100 | $2.36 | $236.00 |
| 500 | $2.1 | $1,050.00 |
| 1,000 | $1.86 | $1,860.00 |
ATMEGA8A-PU Overview
An 8-bit microcontroller (MCU) is a single-chip processor combining a CPU core, program and data memory, timers, and peripherals such as UART, SPI, and I2C. MCUs sit at the bottom of the embedded hierarchy (MCU -> embedded processor -> SoC) and are the standard choice for cost-sensitive control tasks where a full application processor is unnecessary. The AVR family uses a Harvard architecture with 32 x 8 general-purpose working registers and mostly single-cycle instruction execution.
Key features include up to 16 MIPS throughput at 16 MHz, a 2-cycle on-chip hardware multiplier, 130 powerful instructions, three flexible timer/counters with compare modes, and read-while-write Flash for self-programming. Operating voltage is 4.5V to 5.5V, making the -PU speed grade ideal for robust 5V industrial designs.
Technical depth: the advanced RISC pipeline executes most instructions in one clock cycle, while the hardware multiplier accelerates math-heavy control loops. Nonvolatile memory endurance of typically 10,000 write cycles for Flash supports field firmware updates via ISP (In-System Programming) through the SPI interface, and the 512B EEPROM retains calibration data through power cycles.
Typical applications include 5V industrial control panels, hobby and educational embedded platforms such as Arduino-compatible boards, appliance motor control, and serial-bridge adapters using the built-in USART.
Design consideration: this -PU speed grade is rated for 16 MHz only in the 4.5-5.5V range; below 4.5V use the L (low-voltage) grade parts such as ATMEGA8L-8PU.
This page adds value beyond the datasheet by synthesizing distributor pricing tiers, drop-in alternatives in the same 28-PDIP footprint, practical design notes, and an alternatives comparison table useful for sourcing decisions.
Drop-in alternatives for ATMEGA8A-PU β 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 ATMEGA8A-PU (same form factor and footprint) β differing in Instructions, ADC, Communication Interfaces, Flash Memory, Throughput.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA8-16PI
β Drop-Inβ In Stock
$1.85 / Unit
View Datasheet βATMEGA8L-8PU
β Drop-Inβ In Stock
$3.08 / Unit
View Datasheet βATMEGA88-20PI
β Drop-Inβ In Stock
$1.85 / Unit
View Datasheet βATMEGA88V-10PU
β Drop-Inβ In Stock
$1.3 / Unit
View Datasheet βATMEGA88PA-PN
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$2.02 / Unit
View Datasheet βATMEGA88V-10PJ
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.82 / Unit
View Datasheet βATMEGA8A-PU Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Maximum Clock Frequency | 16 MHz |
| Flash Memory | 8 KB (4K x 16) ISP |
| SRAM | 1 KB |
| EEPROM | 512 B |
| Operating Voltage Range | 4.5 V to 5.5 V |
| General Purpose I/O Lines | 23 |
| Throughput | 16 MIPS at 16 MHz |
| Instructions | 130 instructions, most single-cycle |
| Working Registers | 32 x 8 general purpose |
| Timers/Counters | Three flexible timer/counters with compare |
| Package | 28-PDIP |
| Mounting Type | Through Hole |
| Life Cycle Stage | Active |
| Series | AVR ATmega |
| Hardware Multiplier | On-chip 2-cycle multiplier |
| Programming Interface | In-System Programming (ISP) via SPI |
ATMEGA8A-PU Pin Configuration
| Pin 1 | PC6 / RESET β Reset input or Port C bit 6 (I/O) |
| Pin 2 | PD0 / RXD β Port D bit 0 / UART receive input |
| Pin 3 | PD1 / TXD β Port D bit 1 / UART transmit output |
| Pin 4 | PD2 / INT0 β Port D bit 2 / external interrupt 0 |
| Pin 5 | PD3 / INT1 β Port D bit 3 / external interrupt 1 |
| Pin 6 | PD4 β Port D bit 4 (I/O, Timer0 T0 input) |
| Pin 7 | VCC β Digital supply voltage (4.5 V to 5.5 V) |
| Pin 8 | GND β Ground |
| Pin 9 | PB6 / XTAL1 β Port B bit 6 / crystal oscillator inverting input |
| Pin 10 | PB7 / XTAL2 β Port B bit 7 / crystal oscillator output |
| Pin 11 | PD5 / T1 β Port D bit 5 (I/O, Timer1 external counter input) |
| Pin 12 | PD6 β Port D bit 6 (I/O, analog comparator AIN0) |
| Pin 13 | PD7 β Port D bit 7 (I/O, analog comparator AIN1) |
| Pin 14 | PB0 β Port B bit 0 (I/O) |
| Pin 15 | PB1 β Port B bit 1 (I/O) |
| Pin 16 | PB2 β Port B bit 2 (I/O) |
| Pin 17 | PB3 / MOSI β Port B bit 3 / SPI master data output (ISP) |
| Pin 18 | PB4 / MISO β Port B bit 4 / SPI master data input (ISP) |
| Pin 19 | PB5 / SCK β Port B bit 5 / SPI clock (ISP) |
| Pin 20 | AVCC β ADC supply voltage |
| Pin 21 | AREF β ADC analog reference voltage |
| Pin 22 | GND β Ground (AGND) |
| Pin 23 | PC0 / ADC0 β Port C bit 0 / ADC channel 0 |
| Pin 24 | PC1 / ADC1 β Port C bit 1 / ADC channel 1 |
| Pin 25 | PC2 / ADC2 β Port C bit 2 / ADC channel 2 |
| Pin 26 | PC3 / ADC3 β Port C bit 3 / ADC channel 3 |
| Pin 27 | PC4 / ADC4 / SDA β Port C bit 4 / ADC channel 4 / TWI data |
| Pin 28 | PC5 / ADC5 / SCL β Port C bit 5 / ADC channel 5 / TWI clock |
Typical Applications
ATMEGA8A-PU is suitable for 6 applications: 5V Industrial Control Panels, Hobby and Educational Embedded Platforms, Serial Communication Bridges, Small Motor Control, Sensor Data Acquisition Nodes, Appliance and Consumer Product Control.
5V Industrial Control Panels
The ATMEGA8A-PU's 4.5-5.5V operating range and through-hole 28-PDIP package make it a natural fit for 5V industrial control panels, relay sequencers, and process monitoring boards. Its 23 GPIO lines directly drive optocoupler inputs, relay coils via transistors, and status LEDs, while three flexible timer/counters with compare modes generate PWM for actuators. The through-hole package withstands vibration and simplifies field servicing with a socketed MCU. In-system programmable 8KB Flash allows technicians to update firmware on site through the SPI ISP header, and the 512B EEPROM stores configuration and calibration values that survive power cycles. Its 130-instruction single-cycle RISC core at 16 MHz (16 MIPS) provides ample headroom for state machines and Modus-style UART protocols.
Recommended
Hobby and Educational Embedded Platforms
The ATMEGA8A-PU is a favorite for educational embedded systems and hobby boards because the DIP-28 package is breadboard-friendly and socketable, allowing students to remove and reuse the chip without special tools. The AVR architecture's 32 x 8 working registers and mostly single-cycle instructions make assembly and C programming predictable, while the free GCC-based AVR toolchain and bootloader ecosystems lower the entry cost. The 8KB Flash accommodates small learning projects: LED multiplexing, keypad scanning, LCD drivers, and sensor polling via I2C (TWI on PC4/PC5) or SPI. On-chip 10-bit ADC channels on Port C read analog sensors directly, and the 16 MIPS throughput handles soft-UART and display refresh tasks comfortably in classroom designs.
Recommended
Serial Communication Bridges
With its built-in USART on PD0/RXD and PD1/TXD, the ATMEGA8A-PU serves well as a protocol converter and serial bridge, for example translating between RS-232 equipment and SPI or I2C peripherals. At 16 MHz the UART supports standard baud rates with low error across the range, and the 1KB SRAM buffers packetized transfers. The 2-cycle hardware multiplier accelerates CRC and checksum computation in protocol handling firmware. Because the design is 5V, it directly interfaces legacy TTL/CMOS serial hardware without level shifting in many cases, and the through-hole package eases prototyping on adapter boards. EEPROM storage retains device addresses and configuration between power cycles, which is important for deployed converter modules.
Recommended
Small Motor Control
Microchip explicitly highlights motor control on the ATmega8A product page, and the ATMEGA8A-PU is well matched to small DC and stepper motor drivers. Timer/counters with compare outputs generate PWM at carrier frequencies from a few hundred hertz to tens of kilohertz, controlling H-bridge drivers through the 23 GPIO lines. The 16 MHz clock gives 256-step PWM resolution up to roughly 62.5 kHz in fast-PWM mode, enabling quiet, efficient drive. Dead-time insertion can be handled in firmware or with gate-driver ICs. The 2-cycle hardware multiplier supports speed calculation loops for encoder feedback. In 5V control cards, the DIP package simplifies prototyping, while the Flash self-programming capability supports production-line firmware loading without removing the device.
Recommended
Sensor Data Acquisition Nodes
The ATMEGA8A-PU integrates a multi-channel 10-bit ADC whose inputs are multiplexed onto Port C (PC0-PC3 as ADC pins plus the differential-capable channels referenced to AREF on pin 21 and AVCC on pin 20), letting one chip read several analog sensors without external conversion ICs. For distributed acquisition nodes in 5V industrial environments, the DIP package allows serviceable socketing, and the I2C (TWI) master/slave interface on PC4/PC5 connects external digital sensors or EEPROMs. The 512B on-chip EEPROM logs calibration constants and node addresses. At 16 MHz, sample scheduling and filtering code execute with margin, and the USART uploads readings to a host controller, making the part cost-effective for temperature, pressure, and potentiometer monitoring points.
Recommended
Appliance and Consumer Product Control
Cost-sensitive appliance controllers - coffee machines, rice cookers, fan speed regulators, and simple white-goods timers - benefit from the ATMEGA8A-PU's combination of low unit price, 5V direct operation from a transformer supply, and robust through-hole assembly. The three timer/counters handle keypad scanning, display multiplexing, and heater or fan PWM concurrently, while brown-out detection and watchdog support reliable reset behavior in noisy mains environments. The 8KB Flash is sufficient for UI logic, safety interlocks, and temperature regulation via the on-chip ADC with an NTC sensor. EEPROM retains user settings and cycle counters through power loss. Field firmware updates via ISP reduce warranty service costs for deployed products.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA8A-PU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8-16PI | ATMEGA8L-8PU | ATMEGA88-20PI | ATMEGA88V-10PU | ATMEGA88PA-PN |
|---|---|---|---|---|---|---|
| Package | 28-PDIP | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Frequency | 16 MHz | 16 MHz | 8 MHz | 20 MHz | 10 MHz | 20 MHz |
| Supply Voltage Range | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.7 V to 5.5 V | 4.5 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Flash Memory | 8 KB | 8 KB | 8 KB | 8 KB | 8 KB | 8 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| EEPROM | 512 B | 512 B | 512 B | 512 B | 512 B | 512 B |
| Firmware Compatibility with ATmega8 | Native (this part) | Identical register map | Identical register map | Port required (AVR094) | Port required (AVR094) | Port required (AVR094) |
Key Differentiators
- 16 MHz maximum clock at full 5V supply (vs ATMEGA8L-8PU)
- Native ATmega8 firmware compatibility (vs ATMEGA88-20PI)
- Cost-effective active 5V legacy part (vs ATMEGA88PA-PN)
Design Notes
Decouple VCC (pin 7) and AVCC (pin 20) with 100 nF ceramic capacitors placed within a few millimeters of each pin, plus a bulk 4.7-10 uF capacitor per board. AVCC must be connected to VCC even if the ADC is unused, per Microchip datasheet requirements, and AREF (pin 21) should have a 100 nF capacitor to GND when using the internal reference. Estimated: at 5 V and 16 MHz the ATmega8A draws roughly 3.6 mA active (datasheet typ.) - well within a linear regulator budget for small control cards.
For the through-hole DIP-28, use a socket for field-programmable designs but choose a low-profile dual-wipe socket to minimize contact resistance in vibration environments. Keep the ISP header (MOSI/MISO/SCK/RESET/VCC/GND) short-routed and away from PWM switch nodes. Route the XTAL1/XTAL2 crystal traces as short as possible with ground guard traces; place the 16 MHz crystal and its two 18-22 pF load capacitors within 10 mm of pins 9 and 10.
Do not confuse speed grades: the -PU grade is valid only from 4.5 V to 5.5 V, and clocking it at 16 MHz below that voltage violates Microchip's specified operating range. When swapping to ATmega88-family parts (ATMEGA88-20PI etc.), remember that per app note AVR094 the register maps differ - peripheral initialization code, interrupt vectors, and fuse settings must be ported, and the lock/fuse bit layout of ATmega88 is not identical to ATmega8. Verify fuse bits (CLKDIV8/CKOUT) on first programming of ATmega88 replacements.
When driving relays or motors from GPIO, keep flyback/freewheeling diodes close to the load and route high-di/dt current loops away from the RESET and analog pins. Enable the internal brown-out detector (BOD fuse at 2.7 V/4.0 V threshold options) so that mains droops do not corrupt EEPROM writes; the watchdog timer should be enabled as a second-level recovery mechanism in deployed appliance controllers.
Compliance Information
RoHS compliance and lead-free status per Microchip product information for the ATMEGA8A family. REACH and halogen-free status not stated in the provided data.
