ATMEGA64L-8AU - 8-bit AVR MCU, 64KB Flash, 8MHz | Microchip
MPN: ATMEGA64L-8AU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.2 | $7.20 |
| 10 | $6.48 | $64.80 |
| 100 | $5.72 | $572.00 |
| 500 | $5.1 | $2,550.00 |
| 1,000 | $4.55 | $4,550.00 |
ATMEGA64L-8AU Overview
An 8-bit microcontroller (MCU) is a self-contained computing device integrating a processor core, memory, and peripherals such as timers, serial interfaces, and ADCs onto a single chip. MCUs sit at the heart of embedded systems, forming the control layer beneath SoCs and processors in the broader semiconductor hierarchy, and execute real-time control loops in industrial, automotive, and consumer products.
Key features of the ATMEGA64L-8AU include 64KB Flash with Read-While-Write capability, an 8-channel 10-bit ADC, four flexible Timer/Counters with compare modes and PWM, two USARTs, a byte-oriented Two-Wire Interface (TWI/I2C), and a Serial Peripheral Interface (SPI). The AVR core executes 130 powerful instructions, most in a single clock cycle, with 32 x 8-bit general-purpose working registers.
Technically, the fully static CMOS core supports low idle and power-down sleep modes, a Real Time Counter with separate oscillator for RTC operation, and a JTAG (IEEE 1149.1 compliant) boundary-scan and on-chip debugging interface. In-system programmability via SPI allows firmware updates without removing the device from the PCB.
Typical applications include industrial control panels, building automation and HVAC controllers, instrumentation front ends using the 10-bit ADC, and legacy embedded systems originally designed around the pin-compatible ATmega103.
Design consideration: choose the L speed grade (8MHz, 2.7-5.5V) only for designs clocked at or below 8MHz; the ATmega64/ATmega64A standard grade is required for 16MHz operation at 5V.
Note: Microchip lists the ATmega64 as a mature product not recommended for new designs, replaced by the ATmega64A. This page synthesizes distributor availability, pin-compatible alternatives, and design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA64L-8AU — 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 ATMEGA64L-8AU (same form factor and footprint) — differing in Timers/Counters, Package, ADC, EEPROM, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA64L-8AQ
✅ Drop-In✓ In Stock
$7.5 / Unit
View Datasheet →ATMEGA64A-AUR
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →ATMEGA64A-MUR
✅ Drop-In✓ In Stock
$4.42 / Unit
View Datasheet →ATMEGA64-16AU
✅ Drop-In✓ In Stock
$7.23 / Unit
View Datasheet →ATMEGA128L-8AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$23.49 / Unit
View Datasheet →ATMEGA640V-8AU
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →ATMEGA64L-8AU Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Architecture | AVR enhanced RISC, 130 instructions |
| Speed | 8 MHz |
| Flash Memory | 64KB (32K x 16) In-System Programmable |
| EEPROM | 2KB |
| SRAM | 4KB |
| Operating Voltage Range | 2.7 V to 5.5 V |
| General Purpose I/O | 53 lines |
| ADC | 8-channel, 10-bit |
| Timers/Counters | 4 (with compare modes and PWM) |
| USART | 2 |
| Serial Interfaces | TWI (I2C-compatible), SPI, 2x USART |
| JTAG | Yes (boundary scan, on-chip debug) |
| RTC | Real Time Counter with separate oscillator |
| Package | 64-TQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| Lifecycle Note | Mature product, not recommended for new designs; replaced by ATmega64A |
ATMEGA64L-8AU Pin Configuration
| Pin 1 | PE0 — Port E bit 0 / RXD0 (USART0 receive) |
| Pin 2 | PE1 — Port E bit 1 / TXD0 (USART0 transmit) |
| Pin 3 | PE2 — Port E bit 2 / XCK0 / AIN0 |
| Pin 4 | PE3 — Port E bit 3 / OC3A / AIN1 |
| Pin 5 | PE4 — Port E bit 4 / OC3B / INT4 |
| Pin 6 | PE5 — Port E bit 5 / OC3C / INT5 |
| Pin 7 | PE6 — Port E bit 6 / T3 / INT6 |
| Pin 8 | PE7 — Port E bit 7 / ICP3 / INT7 |
| Pin 9 | PB7 — Port B bit 7 / OC2 / OC1C |
| Pin 10 | PB6 — Port B bit 6 / OC1B |
| Pin 11 | PB5 — Port B bit 5 / OC1A |
| Pin 12 | PB4 — Port B bit 4 / OC0 |
| Pin 13 | PB3 — Port B bit 3 / MISO (SPI) |
| Pin 14 | PB2 — Port B bit 2 / MOSI (SPI) |
| Pin 15 | PB1 — Port B bit 1 / SCK (SPI) |
| Pin 16 | PB0 — Port B bit 0 / SS (SPI slave select) |
| Pin 17 | GND — Ground |
| Pin 18 | VCC — Digital supply voltage |
| Pin 19 | PA0 — Port A bit 0 / ADC0 |
| Pin 20 | PA1 — Port A bit 1 / ADC1 |
| Pin 21 | PA2 — Port A bit 2 / ADC2 |
| Pin 22 | PA3 — Port A bit 3 / ADC3 |
| Pin 23 | PA4 — Port A bit 4 / ADC4 |
| Pin 24 | PA5 — Port A bit 5 / ADC5 |
| Pin 25 | PA6 — Port A bit 6 / ADC6 |
| Pin 26 | PA7 — Port A bit 7 / ADC7 |
| Pin 27 | PC7 — Port C bit 7 / TDI (JTAG) |
| Pin 28 | PC6 — Port C bit 6 / TDO (JTAG) |
| Pin 29 | PC5 — Port C bit 5 / TMS (JTAG) |
| Pin 30 | PC4 — Port C bit 4 / TCK (JTAG) |
| Pin 31 | PC3 — Port C bit 3 |
| Pin 32 | PC2 — Port C bit 2 |
| Pin 33 | PC1 — Port C bit 1 |
| Pin 34 | PC0 — Port C bit 0 |
| Pin 35 | PD7 — Port D bit 7 / ICP1 |
| Pin 36 | PD6 — Port D bit 6 / T1 |
| Pin 37 | PD5 — Port D bit 5 / T0 |
| Pin 38 | PD4 — Port D bit 4 / XCK1 |
| Pin 39 | PD3 — Port D bit 3 / INT3 / TXD1 |
| Pin 40 | PD2 — Port D bit 2 / INT2 / RXD1 |
| Pin 41 | PD1 — Port D bit 1 / INT1 / SCL (TWI) |
| Pin 42 | PD0 — Port D bit 0 / INT0 / SDA (TWI) |
| Pin 43 | VCC — Digital supply voltage |
| Pin 44 | GND — Ground |
| Pin 45 | PF0 — Port F bit 0 / ADC0 |
| Pin 46 | PF1 — Port F bit 1 / ADC1 |
| Pin 47 | PF2 — Port F bit 2 / ADC2 |
| Pin 48 | PF3 — Port F bit 3 / ADC3 |
| Pin 49 | PF4 — Port F bit 4 / ADC4 / TCK (JTAG alt) |
| Pin 50 | PF5 — Port F bit 5 / ADC5 / TMS (JTAG alt) |
| Pin 51 | PF6 — Port F bit 6 / ADC6 / TDO (JTAG alt) |
| Pin 52 | PF7 — Port F bit 7 / ADC7 / TDI (JTAG alt) |
| Pin 53 | AGND — Analog ground |
| Pin 54 | AREF — Analog reference voltage for ADC |
| Pin 55 | GND — Ground |
| Pin 56 | AVCC — Analog supply voltage for ADC |
| Pin 57 | PG0 — Port G bit 0 / WR (external memory write) |
| Pin 58 | PG1 — Port G bit 1 / RD (external memory read) |
| Pin 59 | PG2 — Port G bit 2 / TOSC2 (RTC oscillator) |
| Pin 60 | PG3 — Port G bit 3 / TOSC1 (RTC oscillator) |
| Pin 61 | PG4 — Port G bit 4 |
| Pin 62 | XTAL2 — Main oscillator output |
| Pin 63 | XTAL1 — Main oscillator input / external clock |
| Pin 64 | RESET — Active-low reset input |
Typical Applications
ATMEGA64L-8AU is suitable for 6 applications: Industrial Control and Automation, Data Acquisition and Instrumentation, Building Automation and HVAC, Legacy ATmega103 Board Replacement, Embedded Communication Nodes, Consumer and Appliance Control Boards.
Industrial Control and Automation
The ATMEGA64L-8AU fits industrial control panels thanks to its 53 programmable I/O lines, four Timer/Counters with PWM, and wide 2.7V to 5.5V operating range that tolerates noisy 5V industrial supplies. Typical roles include relay sequencing, stepper/servo pulse generation, and HMI button/LED scanning, all executed by the single-cycle AVR core at up to 8 MIPS. The 64KB Flash accommodates protocol stacks and state machines without external memory, while the 2KB EEPROM stores setpoints and counters across power cycles. In-system programming through SPI lets technicians field-update firmware without desoldering, and JTAG supports on-chip debug during commissioning, reducing bring-up time on the production line.
Recommended
Data Acquisition and Instrumentation
With an 8-channel, 10-bit ADC and an internal bandgap reference, the ATMEGA64L-8AU serves multi-channel measurement nodes such as temperature, pressure, and voltage front ends. Free-running or single-conversion ADC modes let firmware balance resolution (10-bit) against sample rate, while the separate Real Time Counter with its own oscillator time-stamps logged events. The 4KB SRAM buffers sample blocks, and the 2KB EEPROM retains calibration constants. The dual USARTs and TWI bus stream results to a host or display over RS-232/RS-485. At 2.7V minimum supply the device also suits battery-powered portable instruments, with power-down sleep modes cutting quiescent drain between measurements.
Recommended
Building Automation and HVAC
HVAC and building-automation controllers benefit from the ATMEGA64L-8AU combination of dual USARTs (for Modbus RTU plus a service port), TWI for connecting RTC and sensor chips, and abundant I/O for damper actuators, valves, and thermostat inputs. The 10-bit ADC reads NTC thermistors across up to eight zones, and four PWM-capable timers modulate fan speeds and proportional valves. Real Time Counter operation with a 32.768 kHz crystal maintains schedules through main-clock sleep states, conserving power in battery-backed zones. The mature, field-proven AVR ecosystem and decades of design collateral make retrofit and service of installed-base controllers straightforward.
Recommended
Legacy ATmega103 Board Replacement
According to the Microchip datasheet, the ATmega64 is 100 percent pin compatible with the ATmega103 and can replace it on current printed circuit boards. EOL ATmega103 sockets can therefore be repopulated with ATMEGA64L-8AU, gaining 64KB Flash, the 10-bit ADC, and JTAG debugging that the ATmega103 lacked. The application note 'Replacing ATmega103 by ATmega64' documents fuse, register, and initialization differences that firmware teams must review before the swap. Because the L speed grade also runs down to 2.7V, boards shipped in both 3.3V and 5V variants can share one BOM line, simplifying procurement of discontinued-memory upgrades.
Recommended
Embedded Communication Nodes
The two independent USARTs of the ATMEGA64L-8AU enable gateway nodes bridging, for example, an RS-485 Modbus field bus and an RS-232 or TTL debug/console link simultaneously. Hardware support for 9-bit multiprocessor framing, the SPI port for RF modules or SD cards, and the TWI bus for configuration EEPROMs let a single TQFP-64 device integrate an entire communication sub-system. The 64KB Flash holds stack, drivers, and web-style configuration logic, while PWM timers generate status beacons or drive carrier LEDs. JTAG boundary scan additionally supports ICT (in-circuit test) coverage of the processor's net connections during board production.
Recommended
Consumer and Appliance Control Boards
Appliance main boards, chargers, and small home devices use the ATMEGA64L-8AU where cost, availability of mature supply, and proven firmware ecosystems matter more than peak performance. The device handles capacitive or mechanical button matrices, buzzer tones, motor PWM, and 10-bit ADC battery monitoring simultaneously with its four timers and eight ADC channels. Operating down to 2.7V supports two-cell battery products, and power-down sleep modes meet low standby-draw targets. The 64-pin TQFP (14x14 mm) is wave-and-reflow friendly and offers enough I/O to eliminate glue logic, cutting BOM count. In-system programming supports final-test firmware flashing on the assembly line.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA64L-8AU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA64L-8AQ | ATMEGA64A-AUR | ATMEGA64-16AU | ATMEGA128L-8AU |
|---|---|---|---|---|---|
| Package | 64-TQFP (14x14 mm) | 64-TQFP (14x14) - same | 64-TQFP (14x14) - same | 64-TQFP (14x14) - same | 64-TQFP (14x14) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Speed | 8 MHz | 8 MHz | 16 MHz | 16 MHz | 8 MHz |
| Operating Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 1.8 V to 5.5 V (ATmega64A) | 4.5 V to 5.5 V | 2.7 V to 5.5 V |
| Flash Memory | 64 KB | 64 KB | 64 KB | 64 KB | 128 KB |
| SRAM | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB |
| EEPROM | 2 KB | 2 KB | 2 KB | 2 KB | 4 KB |
| Lifecycle Status | Mature / NRND (replaced by ATmega64A) | Mature / NRND | Active (recommended) | Mature / NRND | Mature / NRND (replaced by ATmega128A) |
Key Differentiators
- 100% pin compatible with ATmega103 (vs ATMEGA128L-8AU)
- Low-voltage L speed grade (vs ATMEGA64-16AU)
- JTAG on-chip debug and boundary scan (vs ATMEGA64A-AUR)
Design Notes
Decouple both VCC pins (18, 43) and AVCC (56) with 100 nF ceramic capacitors placed within a few millimeters of each pin, plus one bulk 10 uF per supply rail. Tie AVCC to VCC through a low-pass LC filter when ADC accuracy matters, and never leave AVCC floating even if the ADC is unused - the datasheet requires AVCC within 0.3V of VCC. Connect AGND (53) to a quiet analog ground island linked to digital ground at a single point to keep ADC switching noise out of measurements.
Verify fuse settings before first programming: the ATmega64 ships with the internal RC oscillator selected; if your board uses an external crystal, set the CKOPT and CKSEL fuses accordingly, and note that wrong SPIEN/JTAGEN fuse states can lock out ISP access. Also remember the RESET pin has an internal pull-up but boards in noisy environments should add an external 10k pull-up and consider a watchdog-enabled brown-out fuse (BODLEVEL) to prevent corruption during 2.7V brownout events near the L-grade minimum supply.
Keep the XTAL1/XTAL2 crystal traces short (under 15 mm) with guard ground, and place load capacitors close to pins 62/63. If using the TOSC1/TOSC2 32.768 kHz RTC oscillator (PG3/PG2), route it away from USART and SPI switching lines to avoid counting glitches. For the TWI bus on PD0/PD1, use 4.7k pull-ups at 100 kHz; at 400 kHz reduce to 2.2k. Series-terminate 22 ohms on SPI SCK lines longer than 100 mm to control ringing.
Compliance Information
AU suffix denotes RoHS-compliant lead-free TQFP package per Microchip ordering-code convention; REACH and halogen-free status not stated in provided data.
