ATMEGA8535L-8PI - 8-bit AVR MCU 8KB Flash 8MHz | Microchip
MPN: ATMEGA8535L-8PI ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.2 | $6.20 |
| 10 | $5.58 | $55.80 |
| 100 | $4.96 | $496.00 |
| 500 | $4.34 | $2,170.00 |
| 1,000 | $3.72 | $3,720.00 |
ATMEGA8535L-8PI Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor in which program memory and data memory are accessed on separate buses, allowing most of its 130 powerful instructions to execute in a single clock cycle. Within the power-management hierarchy, a microcontroller unit (MCU) integrates CPU, memory, timers, and communication peripherals on one die, making it the central control element of an embedded system.
Key features include the AVR advanced RISC core with 32 general-purpose working registers delivering up to 16 MIPS throughput at 16 MHz (8 MIPS at the 8 MHz speed grade of the L variant), In-System Programmable (ISP) Flash with Read-While-Write capability, and a wide 2.7V to 5.5V operating voltage range unique to the ATmega8535L low-voltage grade. Peripheral integration covers three flexible Timer/Counters with compare modes, a byte-oriented Two-wire Serial Interface (I2C/TWI), a programmable serial USART, and an SPI interface for 544-byte SRAM expansion. Six software-selectable power-saving sleep modes (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, Extended Standby) enable battery-operated designs.
The 8-channel 10-bit successive-approximation ADC supports single-ended and differential conversions, useful for direct analog sensor acquisition. The JTAG-less, low-cost design targets classic through-hole prototyping on 0.600 in DIP sockets.
Typical applications include industrial control and automation, motor and HVAC control boards, sensor data acquisition nodes, and educational/hobby embedded platforms where DIP packages simplify prototyping and in-circuit programming.
Design consideration: the ATmega8535L speed grade limits operation to 0-8 MHz and 2.7-5.5V; for 16 MHz 4.5-5.5V operation choose the ATMEGA8535-16P grade instead, keeping the identical footprint.
This page synthesizes verified distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA8535L-8PI — 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-8PI (same form factor and footprint) — differing in Communication Interfaces, Operating Temperature, Package, EEPROM, SRAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA8535-16PJ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$3.4 / Unit
View Datasheet →ATMEGA8535L-8PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.85 / Unit
View Datasheet →AT90S8535-8PI
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA16-16PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$3.88 / Unit
View Datasheet →ATMEGA8515-16PI
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA32A-PU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$3.85 / Unit
View Datasheet →ATMEGA8535L-8PI Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-bit |
| Speed | 8 MHz |
| Flash Program Memory | 8 KB (4K x 16) |
| EEPROM | 512 bytes |
| RAM | 512 bytes |
| Operating Voltage Range | 2.7 V to 5.5 V |
| Number of I/O | 32 |
| ADC Resolution | 10-bit |
| ADC Channels | 8 |
| Communication Interfaces | I2C, SPI, UART/USART |
| Timers/Counters | 3 |
| Instructions | 130 powerful instructions, most single-cycle |
| Sleep Modes | 6 (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, Extended Standby) |
| Throughput | up to 16 MIPS at 16 MHz (8 MIPS at 8 MHz) |
| Package | 40-PDIP (0.600 in, 15.24 mm) |
| Mounting Type | Through Hole |
| Flash Programming | In-System Programmable with Read-While-Write |
| Extended SRAM Interface | SPI interface to 544-byte SRAM |
| Operating Temperature | -40C to +85C (industrial) |
ATMEGA8535L-8PI Pin Configuration
| Pin 1 | PB0 (XCK/T0) — PORTB bit 0 / USART external clock / Timer0 external clock |
| Pin 2 | PB1 (T1) — PORTB bit 1 / Timer1 external clock |
| Pin 3 | PB2 (AIN0/INT2) — PORTB bit 2 / analog comparator positive input / external interrupt 2 |
| Pin 4 | PB3 (AIN1/OC0) — PORTB bit 3 / analog comparator negative input / Timer0 output compare |
| Pin 5 | PB4 (SS) — PORTB bit 4 / SPI slave select |
| Pin 6 | PB5 (MOSI) — PORTB bit 5 / SPI master output, slave input |
| Pin 7 | PB6 (MISO) — PORTB bit 6 / SPI master input, slave output |
| Pin 8 | PB7 (SCK) — PORTB bit 7 / SPI serial clock |
| Pin 9 | RESET — Reset input, active low |
| Pin 10 | VCC — Digital supply voltage (2.7 V to 5.5 V) |
| Pin 11 | GND — Ground |
| Pin 12 | XTAL2 — Oscillator amplifier output |
| Pin 13 | XTAL1 — Oscillator amplifier input / external clock input |
| Pin 14 | PD0 (RXD) — PORTD bit 0 / USART receive data |
| Pin 15 | PD1 (TXD) — PORTD bit 1 / USART transmit data |
| Pin 16 | PD2 (INT0) — PORTD bit 2 / external interrupt 0 |
| Pin 17 | PD3 (INT1) — PORTD bit 3 / external interrupt 1 |
| Pin 18 | PD4 (OC1B) — PORTD bit 4 / Timer1 output compare B |
| Pin 19 | PD5 (OC1A) — PORTD bit 5 / Timer1 output compare A |
| Pin 20 | PD6 (ICP1) — PORTD bit 6 / Timer1 input capture |
| Pin 21 | PD7 (OC2) — PORTD bit 7 / Timer2 output compare |
| Pin 22 | PC0 (SCL) — PORTC bit 0 / TWI serial clock |
| Pin 23 | PC1 (SDA) — PORTC bit 1 / TWI serial data |
| Pin 24 | PC2 (TCK) — PORTC bit 2 / test clock |
| Pin 25 | PC3 (TMS) — PORTC bit 3 / test mode select |
| Pin 26 | PC4 (TDO) — PORTC bit 4 / test data output |
| Pin 27 | PC5 (TDI) — PORTC bit 5 / test data input |
| Pin 28 | PC6 (TOSC1) — PORTC bit 6 / timer oscillator input |
| Pin 29 | PC7 (TOSC2) — PORTC bit 7 / timer oscillator output |
| Pin 30 | AVCC — Analog supply voltage for ADC and PORTA |
| Pin 31 | GND — Ground |
| Pin 32 | AREF — ADC analog reference voltage |
| Pin 33 | PA7 (ADC7) — PORTA bit 7 / ADC channel 7 |
| Pin 34 | PA6 (ADC6) — PORTA bit 6 / ADC channel 6 |
| Pin 35 | PA5 (ADC5) — PORTA bit 5 / ADC channel 5 |
| Pin 36 | PA4 (ADC4) — PORTA bit 4 / ADC channel 4 |
| Pin 37 | PA3 (ADC3) — PORTA bit 3 / ADC channel 3 |
| Pin 38 | PA2 (ADC2) — PORTA bit 2 / ADC channel 2 |
| Pin 39 | PA1 (ADC1) — PORTA bit 1 / ADC channel 1 |
| Pin 40 | PA0 (ADC0) — PORTA bit 0 / ADC channel 0 |
Typical Applications
ATMEGA8535L-8PI is suitable for 6 applications: Industrial Control and Automation, Sensor Data Acquisition, Embedded Education and Prototyping, Motor and HVAC Control, Serial Communication Gateways, Security and Access Control Panels.
Industrial Control and Automation
The ATMEGA8535L-8PI fits industrial control boards that need deterministic 8-bit control, multiple communication buses, and moderate analog acquisition in one through-hole device. Its three Timer/Counters with compare modes directly generate PWM for actuator and heater control, while the byte-oriented TWI (I2C) and SPI interfaces connect panel displays and EEPROM expansion. The industrial -40C to +85C temperature range suits factory-floor enclosures. Operating from 2.7V to 5.5V, it tolerates relaxed 3.3V or 5V logic rails. Designers typically clock it from an 8 MHz crystal via XTAL1/XTAL2, giving one MIPS per MHz; heavier signal-processing loads should be offloaded to hardware timers rather than software loops to stay within the 8 MHz budget.
Recommended
Sensor Data Acquisition
The integrated 8-channel 10-bit successive-approximation ADC is the core reason the ATMEGA8535L-8PI suits multi-sensor acquisition nodes. Up to eight single-ended inputs on PORTA (PA0-PA7) sample temperature, pressure, and level signals at moderate rates, and differential modes cancel common-mode noise on bridge sensors such as strain gauges. The ADC Noise Reduction sleep mode silences the CPU clock during conversions, improving effective noise-free resolution. AVCC on pin 30 must be tied to a clean analog supply and AREF (pin 32) decoupled for rated accuracy. At 8 MHz the L grade provides ample sampling bandwidth for slow physical-process monitoring while consuming less dynamic power than 16 MHz grades.
Recommended
Embedded Education and Prototyping
The 0.600 in 40-pin PDIP package is the defining advantage for education: the ATMEGA8535L-8PI plugs into standard DIP sockets and breadboard adapters, can be removed for external ISP programming, and tolerates repeated insertion cycles that damage fine-pitch SMD parts. Its 2.7V to 5.5V range lets students experiment with both 3.3V and 5V logic without level shifting, and 32 general-purpose I/O lines support LED matrices, keypads, LCDs, and UART terminal exercises in a single curriculum. The widely documented AVR architecture (130 mostly single-cycle instructions, 32 working registers) remains a staple of embedded-systems teaching, and ISP Flash enables reprogramming without removing the chip from the target board.
Recommended
Motor and HVAC Control
For fan, pump, and HVAC damper control, the ATMEGA8535L-8PI combines PWM generation from its Timer/Counters with ADC feedback from current-sense or NTC inputs, closing the control loop in firmware with proportional-integral routines. The TWI bus reads digital temperature sensors on the same two wires used for configuration EEPROMs, reducing harness complexity in distributed HVAC units. Its wide 2.7V to 5.5V supply tolerates sagging unregulated rails during motor start transients. A practical consideration is PCB-level protection: flyback from inductive loads must be clamped away from the I/O pins, and the ADC sampling instant should be synchronized away from PWM switching edges to avoid rail noise corrupting readings.
Recommended
Serial Communication Gateways
With hardware UART/USART, TWI (I2C), and SPI operating concurrently, the ATMEGA8535L-8PI serves as a protocol bridge in legacy equipment: for example, converting a modbus-style UART link from a host controller into TWI for slave peripherals, or buffering data into SPI serial memories for local logging. The SPI also expands external 544-byte SRAM when 512 bytes of internal RAM proves tight for message buffers. Running at 8 MIPS, it comfortably sustains 38.4 kbaud UART traffic with interrupt-driven ring buffers, though budgets should reserve headroom for CRC computation. Sleep modes allow the gateway to idle at microamp-level current between transactions in battery-backed installations.
Recommended
Security and Access Control Panels
Access-control and small alarm panels benefit from the ATMEGA8535L-8PI balance of I/O count, EEPROM, and sleep modes. The 32 GPIO lines scan keypads, drive relays, and read door sensors; the 512-byte EEPROM stores calibration data, user codes, and tamper counters through power cycles without external NVRAM. Power-down and Standby sleep modes support mains-failure battery operation, waking via external interrupts on PORTD level changes. The 8 MHz clock keeps response latency to keypad presses well below perceptible thresholds. Because these panels often run for a decade, the mature, long-documented ATmega8535 family - with its extensive errata history and stable datasheet (Microchip document 2502) - provides predictable behavior for compliance-critical designs.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA8535L-8PI — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8535-16PJ | ATMEGA8535L-8PU | AT90S8535-8PI | ATMEGA16-16PU | ATMEGA32A-PU |
|---|---|---|---|---|---|---|
| Package | 40-PDIP (0.600 in) | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same | 40-PDIP - same |
| Brand | Microchip Technology (Atmel legacy) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Speed | 8 MHz | 16 MHz | 8 MHz | 8 MHz | 16 MHz | 16 MHz |
| Operating Voltage | 2.7 V to 5.5 V | 4.5 V to 5.5 V | 2.7 V to 5.5 V | 4.0 V to 6.0 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Flash Memory | 8 KB | 8 KB | 8 KB | 8 KB | 16 KB | 32 KB |
| SRAM | 512 bytes | 512 bytes | 512 bytes | 512 bytes | 1 KB | 2 KB |
| ADC | 8-channel 10-bit | 8-channel 10-bit | 8-channel 10-bit | 8-channel 10-bit | 8-channel 10-bit | 8-channel 10-bit |
| Finish / RoHS | Lead-free (PI) | Lead-free | Tin-lead (legacy) | Legacy generation | Tin-lead (legacy) | Lead-free (RoHS) |
Key Differentiators
- Widest supply range in the family (vs ATMEGA8535-16PJ)
- RoHS lead-free finish (vs ATMEGA8535L-8PU)
- Integrated ADC (vs ATMEGA8515-16PI)
- Legacy register-map compatibility (vs ATMEGA32A-PU)
Design Notes
Connect VCC (pin 10) and AVCC (pin 30) to a decoupled 2.7V-5.5V rail. Even when the ADC is unused, Microchip requires AVCC to be tied to VCC through a low-pass filter (e.g., 10 uH inductor or ferrite bead plus 0.1 uF capacitor) to guarantee specified device operation. Decouple each supply pin with 0.1 uF ceramic capacitors placed within a few millimeters of the pins, and add 4.7 uF to 10 uF of bulk capacitance near the socket.
Keep the analog reference (AREF, pin 32) clean: connect a 0.1 uF capacitor from AREF to ground and never drive it with a low-impedance source without a series resistor, or the internal reference can be damaged. Route ADC input traces on PORTA away from XTAL and PWM output traces (PD4/PD5/PD7). Ground pin 31 (GND) carries ADC return current - give it a solid, short connection to the analog ground plane rather than daisy-chaining to the digital ground.
The L speed grade is hard-limited to 0-8 MHz: overclocking the ATMEGA8535L-8PI to 16 MHz violates the datasheet speed/voltage derating and causes unreliable execution. Fuse configuration is also the most common field failure - setting SPIEN off or selecting an external clock source without a clock bricks the device; keep a parallel programmer or high-voltage parallel programmer available for fuse recovery. Finally, RESET (pin 9) needs a 10 kOhm pull-up for noise immunity on breadboarded designs.
Estimated: at 5.5V and 8 MHz with all 32 I/O pins sourcing 20 mA worst case (not a realistic load), dissipation remains under 0.5 W, and the 40-PDIP DIP-40 plastic package dissipates this comfortably in still air without a heatsink. In sleep-dominated designs (Power-down mode) average dissipation is in the milliwatt range. No thermal management is required for typical use; simply avoid continuous short-circuit currents on I/O pins, which are internally limited but thermally destructive if sustained.
Compliance Information
The PI suffix denotes industrial temperature grade with current-production lead-free (RoHS) finish; the PU suffix variant uses legacy tin-lead plating. Verify RoHS/REACH certificates with the supplier at order time.
