ATMEGA8535L-8PU - 8KB Flash AVR MCU, 8MHz, DIP-40 | Microchip
MPN: ATMEGA8535L-8PU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.35 | $4.35 |
| 10 | $3.98 | $39.80 |
| 100 | $3.61 | $361.00 |
| 500 | $3.24 | $1,620.00 |
| 1,000 | $2.92 | $2,920.00 |
ATMEGA8535L-8PU Overview
An AVR microcontroller is a single-chip computer built around the AVR enhanced RISC architecture, in which most of the 130 powerful instructions execute in a single clock cycle. Within the power-management hierarchy, an MCU such as the ATmega8535 combines a CPU core, program memory, data memory, peripherals, and I/O into one package, replacing multi-chip processor-plus-logic solutions in embedded systems.
Key features include 32 programmable I/O lines, an 8-channel 10-bit A/D converter for direct analog sensor connection, and 3 timers/counters (two 8-bit and one 16-bit) for waveform generation and event counting. The L suffix denotes the low-voltage grade, operating from 2.7V to 5.5V at speeds of 0-8 MHz, which suits battery-powered designs.
The AVR core achieves roughly 1 MIPS per MHz of throughput thanks to its Harvard architecture with separate program and data buses, plus a 2-cycle hardware multiplier. Six software-selectable power-saving modes (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, and Extended Standby) let firmware trade wake-up latency for microamp-level sleep current. In-System Programmable Flash with 1,000 write/erase cycles enables field firmware updates via SPI without removing the device from the board.
Typical applications include industrial control panels, sensor data loggers using the on-chip 10-bit ADC, motor control and PWM-based actuators via the timer output-compare channels, hobbyist and educational embedded systems (the through-hole PDIP package is breadboard-friendly), and low-power battery instruments.
A key design consideration: at 2.7V operation the maximum clock is limited by the L-grade speed curve, so verify the VCC-versus-frequency relationship in the manufacturer datasheet before overclocking; also budget a 0.1uF decoupling capacitor directly across VCC/GND and keep the analog reference (AREF) path clean for ADC accuracy.
This page synthesizes distributor pricing from multiple sources, drop-in alternatives within the same DIP-40 footprint, pinout data, and practical design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATMEGA8535L-8PU 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 ATMEGA8535L-8PU (same form factor and footprint).
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA8535L-8PI
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA8535-16PU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA16A-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA16-16PU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$3.88 / Unit
View Datasheet βATMEGA32A-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA8535L-8PU Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR enhanced RISC, 8-bit |
| Program Memory (Flash) | 8 KB (4K x 16), In-System Programmable |
| SRAM | 512 B |
| EEPROM | 512 B |
| Maximum Clock Frequency | 8 MHz |
| Supply Voltage Range | 2.7 V to 5.5 V (ATmega8535L grade) |
| I/O Lines | 32 programmable |
| ADC | 8-channel, 10-bit |
| Timers/Counters | Two 8-bit, one 16-bit |
| Packages Available | 40-pin PDIP, 44-lead TQFP, 44-lead PLCC, 44-pad QFN/MLF |
| This Device Package | 40-PDIP (0.600 in, 15.24 mm) |
| Sleep Modes | 6 (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, Extended Standby) |
| Instructions | 130 powerful instructions, mostly single-cycle |
| Throughput | Up to 8 MIPS at 8 MHz (L grade) |
| Interfaces | SPI, UART, TWI (I2C-compatible) |
| Operating Temperature (PU suffix) | 0C to +70C |
| Mounting Type | Through Hole |
ATMEGA8535L-8PU Pin Configuration
| Pin 1 | PB0 (T0/XCK) β Port B bit 0 / Timer0 counter input / USART external clock |
| Pin 2 | PB1 (T1) β Port B bit 1 / Timer1 counter input |
| Pin 3 | PB2 (AIN0/INT2) β Port B bit 2 / Analog comparator positive input / External interrupt 2 |
| Pin 4 | PB3 (AIN1/OC0) β Port B bit 3 / Analog comparator negative input / Timer0 output compare PWM |
| Pin 5 | PB4 (SS) β Port B bit 4 / SPI slave select |
| Pin 6 | PB5 (MOSI) β Port B bit 5 / SPI master output slave input / ISP programming |
| Pin 7 | PB6 (MISO) β Port B bit 6 / SPI master input slave output / ISP programming |
| Pin 8 | PB7 (SCK) β Port B bit 7 / SPI serial clock / ISP programming |
| Pin 9 | RESET β Active-low reset input / ISP programming pin |
| Pin 10 | VCC β Digital supply voltage (2.7V to 5.5V) |
| Pin 11 | GND β Ground |
| Pin 12 | XTAL2 β Inverting oscillator amplifier output |
| Pin 13 | XTAL1 β Inverting oscillator amplifier input / external clock input |
| Pin 14 | PD0 (RXD) β Port D bit 0 / USART receive input |
| Pin 15 | PD1 (TXD) β Port D bit 1 / USART transmit output |
| Pin 16 | PD2 (INT0) β Port D bit 2 / External interrupt 0 |
| Pin 17 | PD3 (INT1) β Port D bit 3 / External interrupt 1 |
| Pin 18 | PD4 (OC1B) β Port D bit 4 / Timer1 output compare B PWM |
| Pin 19 | PD5 (OC1A) β Port D bit 5 / Timer1 output compare A PWM |
| Pin 20 | PD6 (ICP1) β Port D bit 6 / Timer1 input capture |
| Pin 21 | PD7 β Port D bit 7 / general purpose I/O |
| Pin 22 | PA0 (ADC0) β Port A bit 0 / ADC channel 0 |
| Pin 23 | PA1 (ADC1) β Port A bit 1 / ADC channel 1 |
| Pin 24 | PA2 (ADC2) β Port A bit 2 / ADC channel 2 |
| Pin 25 | PA3 (ADC3) β Port A bit 3 / ADC channel 3 |
| Pin 26 | PA4 (ADC4) β Port A bit 4 / ADC channel 4 |
| Pin 27 | PA5 (ADC5) β Port A bit 5 / ADC channel 5 |
| Pin 28 | PA6 (ADC6) β Port A bit 6 / ADC channel 6 |
| Pin 29 | PA7 (ADC7) β Port A bit 7 / ADC channel 7 |
| Pin 30 | AREF β ADC analog reference voltage |
| Pin 31 | GND β Ground |
| Pin 32 | AVCC β ADC supply voltage (connect to VCC through low-pass filter) |
| Pin 33 | PC7 (TCK) β Port C bit 7 / JTAG test clock |
| Pin 34 | PC6 (TMS) β Port C bit 6 / JTAG test mode select |
| Pin 35 | PC5 (TDI) β Port C bit 5 / JTAG test data input |
| Pin 36 | PC4 (TDO) β Port C bit 4 / JTAG test data output |
| Pin 37 | PC3 (TMS) β Port C bit 3 / general purpose I/O |
| Pin 38 | PC2 (TCK) β Port C bit 2 / general purpose I/O |
| Pin 39 | PC1 (TDO) β Port C bit 1 / general purpose I/O |
| Pin 40 | PC0 (TDI) β Port C bit 0 / general purpose I/O |
Typical Applications
ATMEGA8535L-8PU is suitable for 6 applications: Industrial Control Panels, Sensor Data Loggers, Motor Control and PWM Actuators, Education and Hobby Embedded Systems, Low-Power Battery Instruments, Legacy 5V Embedded Upgrades and Repairs.
Industrial Control Panels
The ATMEGA8535L-8PU fits industrial control and monitoring panels where 32 I/O lines drive relays, indicators, and buttons while the 8-channel 10-bit ADC reads potentiometers, thermistors, and 4-20mA sensor front-ends. Its 130 single-cycle AVR instructions deliver deterministic 8 MIPS-class timing for polling loops and interrupt-driven control, and the 16-bit timer generates precise PWM for actuator control. In 5V industrial environments the wide 2.7V-5.5V L-grade supply range tolerates noisy rails, and the through-hole PDIP-40 package simplifies servicing and field replacement on legacy panel PCBs. Six sleep modes including Power-down allow the controller to idle at microamp-level current between events in battery-backed installations.
Recommended
Sensor Data Loggers
For battery-powered data loggers, the ATMEGA8535L-8PU offers the 8-channel, 10-bit successive-approximation ADC to digitize up to eight analog sensors without external conversion ICs, cutting BOM cost and board area. The 512B EEPROM stores calibration constants and configuration that survive power loss, while the 512B SRAM buffers sample records between UART or SPI writes to external storage. In ADC Noise Reduction sleep mode the core halts during conversions to minimize digital noise, improving effective resolution. At 2.7V operation the MCU still supports meaningful clock speeds for burst-then-sleep acquisition cycles, and Power-save mode with a 32.768 kHz watch crystal enables long-duration interval logging at minimal average current.
Recommended
Motor Control and PWM Actuators
The ATMEGA8535L-8PU generates PWM for DC motor and actuator control using its two 8-bit and one 16-bit timers with output-compare channels (OC0, OC1A, OC1B), achieving hardware-timed waveforms independent of software jitter. The 16-bit Timer/Counter1 supports input capture for tachometer feedback and frequency measurement, enabling closed-loop speed regulation. Driving gate drivers or logic-level MOSFETs directly from the 5V I/O pins keeps the design simple; combine the MCU with a MOSFET driver stage for higher-current loads. The ADC reads current-sense and position-feedback signals for PI control loops executed in firmware at 8 MHz, adequate for servo update rates in the hundreds of hertz to low kilohertz range.
Recommended
Education and Hobby Embedded Systems
The through-hole 40-pin PDIP package makes the ATMEGA8535L-8PU ideal for breadboard prototyping and university embedded-systems coursework, where students wire crystals, reset circuits, and ISP headers by hand. SPI In-System Programming means firmware can be flashed repeatedly without pulling the chip, and the AVR instruction set is widely taught with free toolchains (AVR-GCC, Microchip Studio). The mix of UART, SPI, TWI, 8-bit/16-bit timers, and a genuine 10-bit ADC covers an entire embedded curriculum in one 8KB device: serial communication, interrupts, analog sampling, and real-time control. The L-grade 2.7V-5.5V supply range also allows safe experiments from both USB 5V and 3.3V logic levels.
Recommended
Low-Power Battery Instruments
In portable instrumentation, the ATMEGA8535L-8PU exploits its six sleep modes to minimize average current: Power-down mode stops the CPU and most clocks while retaining register contents, waking on external interrupts for button presses or threshold events. The 10-bit ADC with its dedicated ADC Noise Reduction mode samples sensors cleanly before the system returns to sleep, and the 512B EEPROM preserves calibration between battery changes. Operating down to 2.7V lets the design drain battery cells further than a fixed 4.5V device would allow, extending usable life per charge cycle. Typical products include handheld meters, environmental monitors, and event counters where sub-100 uA standby current and instant wake-up are both required.
Recommended
Legacy 5V Embedded Upgrades and Repairs
For maintaining legacy 5V equipment, the ATMEGA8535L-8PU is a practical replacement controller because it runs the full industrial 5V rail, is still an active Microchip part with distributor stock (13,704 pieces at Heisener as of 2026-09-14), and offers the pin-compatible 40-pin DIP-40 footprint that older AVR boards already use. Firmware compatibility within the ATmega8535 family (8PU, 8PI, 16PU variants) allows direct board swaps without PCB changes. The 8KB Flash and 512B SRAM match the memory envelope of countless 1990s-2000s controller designs, and SPI ISP support lets technicians re-flash updated firmware in the field with a simple programmer, keeping discontinued-era machinery in service.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA8535L-8PU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8535L-8PI | ATMEGA8535-16PU | ATMEGA16A-PU | ATMEGA32A-PU |
|---|---|---|---|---|---|
| Package | 40-PDIP | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 8 KB | 8 KB | 8 KB | 16 KB | 32 KB |
| SRAM | 512 B | 512 B | 512 B | 1 KB | 2 KB |
| Max Clock Frequency | 8 MHz | 8 MHz | 16 MHz | 16 MHz | 16 MHz |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 4.5 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| ADC | 8-ch, 10-bit | 8-ch, 10-bit | 8-ch, 10-bit | 8-ch, 10-bit | 8-ch, 10-bit |
| Operating Temperature | 0C to +70C | -40C to +85C | 0C to +70C | -40C to +85C | -40C to +85C |
Key Differentiators
- Wide low-voltage operating range (vs ATMEGA8535-16PU)
- Breadboard-friendly through-hole package retained in active production (vs ATMEGA32A-PU)
- Trade-off: lower maximum throughput (vs ATMEGA16A-PU)
Design Notes
Decouple VCC (pin 10) with a 100 nF ceramic capacitor placed within a few millimeters of the pin, and decouple AVCC (pin 32) separately through a 10 uH inductor or low-pass RC from VCC with its own 100 nF capacitor to the analog ground, as recommended in the Microchip ATmega8535 datasheet. For through-hole DIP-40 prototyping, use a socket and keep crystal traces (XTAL1/XTAL2, pins 13/12) short with 22 pF load capacitors. Tie RESET (pin 9) to VCC via a 10 k pull-up if not using external programming.
Verify the clock-versus-voltage relationship before finalizing the design: the L grade (2.7V-5.5V) supports 0-8 MHz, but at 2.7V the safe maximum frequency is significantly lower than at 5V. Estimated: a design running at 5V/8 MHz dissipates on the order of tens of milliwatts (active current is in the mA range per datasheet), so no heatsink considerations apply. Avoid switching from the ATMEGA8535L-8PU to the ATMEGA8535-16PU in 3.3V systems, since the non-L grade requires at least 4.5V.
Port A (pins 22-29) is dual-function ADC input and general I/O; do not use ADC channels as digital outputs while conversions are in progress. AREF (pin 30) must not be driven by an external voltage while the internal reference is selected, and should be decoupled to GND with 100 nF when an external reference is used. Also note that ISP programming shares PB5/PB6/PB7 (pins 6/7/8) and RESET (pin 9), so series resistors should isolate SPI peripherals during programming to avoid bus contention.
Compliance Information
Compliance status not stated in the provided verified data; the PU package on modern Microchip AVR production is typically RoHS-compliant, but confirm on the official Microchip product page before design-in.
