ATXMEGA256A3U-AU - 256KB Flash 32MHz 8/16-bit AVR XMEGA MCU | Microchip
N.º da peça: ATXMEGA256A3U-AU ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $14.5 | $14,50 |
| 10 | $12.95 | $129,50 |
| 100 | $11.4 | $1.140,00 |
| 500 | $10.2 | $5.100,00 |
| 1.000 | $9.1 | $9.100,00 |
ATXMEGA256A3U-AU Visão geral
An 8/16-bit microcontroller (MCU) is a programmable system-on-a-chip that combines a CPU, Flash program memory, SRAM, EEPROM, and a rich set of peripherals on a single die. MCUs are the highest-volume category of integrated circuits and serve as the digital core of nearly every embedded product - from battery-powered IoT nodes to industrial motor drives - occupying the middle of the silicon hierarchy between simple discrete logic and full microprocessors.
Key features include 16 KB SRAM, 4 KB EEPROM, a 4-channel DMA controller, an 8-channel event system, and 34 programmable I/O lines. The device operates from a 2.7V to 3.6V supply, supports LVTTL/LVCMOS-compatible I/O, and includes multiple communication interfaces (USART, SPI, TWI) plus a 12-channel 12-bit ADC and analog comparators. The A3U variant adds a USB 2.0 Full-Speed device interface absent from the non-U A3 series.
The ATXMEGA256A3U uses a Harvard-architecture AVR CPU with a 3-stage pipeline and hardware multiplier, achieving 1 MIPS per MHz. The peripheral event system lets peripherals trigger one another without CPU intervention, freeing the core for application code. The 4-channel DMA controller can move data between peripherals and memory autonomously, further reducing CPU load for streaming or signal-processing tasks.
Typical applications include building automation, industrial control, low-power IoT sensor nodes, motor control, metering, USB peripherals, and human-machine interfaces (HMI) with LCD segments. The wide peripheral set and large Flash make it well suited to data logging, LCD-keypad control panels, and protocol bridges that previously required external logic.
When designing with this MCU, allocate adequate decoupling (typically 100 nF plus 10 uF bulk) close to each VCC pin, and follow the XMEGA AU manual guidance for PDI programming interface routing. The 64-pin TQFP footprint is shared with the rest of the ATxmega A3U family, allowing easy migration to the 192A3U, 128A3U, or 64A3U derivatives by code recompilation.
Alternativas drop-in para ATXMEGA256A3U-AU — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Variantes desta série
Modelos da mesma série compatíveis como drop-in com ATXMEGA256A3U-AU (mesmo formato e footprint) — diferindo em Operating Temperature, Program Memory (Flash), RoHS Status, USB Interface.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
ATXMEGA256A3U-AUR
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
ATXMEGA192A3U-AU
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
ATXMEGA128A3U-AU
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
ATXMEGA64A3U-AU
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
ATXMEGA256A3U-ANR
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
ATXMEGA256A3U-AU Classificações máximas e características elétricas
| Core Architecture | AVR enhanced RISC (8/16-bit) |
| Family | AVR XMEGA A3U |
| Program Memory (Flash) | 256 KB (128K x 16) |
| Boot Code Section | 8 KB |
| SRAM | 16 KB |
| EEPROM | 4 KB |
| Maximum CPU Speed | 32 MHz (32 MIPS) |
| Supply Voltage (VCC) | 2.7 V to 3.6 V |
| I/O Pins | 34 programmable I/O lines |
| DMA Channels | 4 |
| Event System Channels | 8 |
| USB Interface | USB 2.0 Full-Speed Device (A3U variant) |
| Encapsulamento | 64-pin TQFP (14x14 mm) |
| Temperatura de operação | -40C to +85C (industrial) |
| Programming Interface | PDI (Program and Debug Interface) |
| Status RoHS | Compliant |
| Tipo de montagem | Surface Mount |
Configuração de pinos do ATXMEGA256A3U-AU
| Pino 1 | VCC — Digital supply voltage (2.7-3.6 V) |
| Pino 2 | PA0 — PORTA bit 0, analog input, peripheral function |
| Pino 3 | PA1 — PORTA bit 1, analog input, peripheral function |
| Pino 4 | PA2 — PORTA bit 2, analog input, peripheral function |
| Pino 5 | PA3 — PORTA bit 3, analog input, peripheral function |
| Pino 6 | PA4 — PORTA bit 4, analog input, peripheral function |
| Pino 7 | PA5 — PORTA bit 5, analog input, peripheral function |
| Pino 8 | PA6 — PORTA bit 6, analog input, peripheral function |
| Pino 9 | PA7 — PORTA bit 7, analog input, peripheral function |
| Pino 10 | GND — Ground |
| Pino 11 | PB0 — PORTB bit 0, peripheral function |
| Pino 12 | PB1 — PORTB bit 1, peripheral function |
| Pino 13 | PB2 — PORTB bit 2, peripheral function |
| Pino 14 | PB3 — PORTB bit 3, peripheral function |
| Pino 15 | PB4 — PORTB bit 4, peripheral function |
| Pino 16 | PB5 — PORTB bit 5, peripheral function |
| Pino 17 | PB6 — PORTB bit 6, peripheral function |
| Pino 18 | PB7 — PORTB bit 7, peripheral function |
| Pino 19 | GND — Ground |
| Pino 20 | VCC — Digital supply voltage |
| Pino 21 | PC0 — PORTC bit 0, peripheral function |
| Pino 22 | PC1 — PORTC bit 1, peripheral function |
| Pino 23 | PC2 — PORTC bit 2, peripheral function |
| Pino 24 | PC3 — PORTC bit 3, peripheral function |
| Pino 25 | PC4 — PORTC bit 4, peripheral function |
| Pino 26 | PC5 — PORTC bit 5, peripheral function |
| Pino 27 | PC6 — PORTC bit 6, peripheral function |
| Pino 28 | PC7 — PORTC bit 7, peripheral function |
| Pino 29 | GND — Ground |
| Pino 30 | VCC — Digital supply voltage |
| Pino 31 | PD0 — PORTD bit 0, peripheral function |
| Pino 32 | PD1 — PORTD bit 1, peripheral function |
| Pino 33 | PD2 — PORTD bit 2, peripheral function |
| Pino 34 | PD3 — PORTD bit 3, peripheral function |
| Pino 35 | PD4 — PORTD bit 4, peripheral function |
| Pino 36 | PD5 — PORTD bit 5, peripheral function |
| Pino 37 | PD6 — PORTD bit 6, peripheral function |
| Pino 38 | PD7 — PORTD bit 7, peripheral function |
| Pino 39 | GND — Ground |
| Pino 40 | VCC — Digital supply voltage |
| Pino 41 | PE0 — PORTE bit 0, peripheral function |
| Pino 42 | PE1 — PORTE bit 1, peripheral function |
| Pino 43 | PE2 — PORTE bit 2, peripheral function |
| Pino 44 | PE3 — PORTE bit 3, peripheral function |
| Pino 45 | PE4 — PORTE bit 4, peripheral function |
| Pino 46 | PE5 — PORTE bit 5, peripheral function |
| Pino 47 | PE6 — PORTE bit 6, TOSC2, peripheral function |
| Pino 48 | PE7 — PORTE bit 7, TOSC1, peripheral function |
| Pino 49 | GND — Ground |
| Pino 50 | VCC — Digital supply voltage |
| Pino 51 | PF0 — PORTF bit 0, analog input, peripheral function |
| Pino 52 | PF1 — PORTF bit 1, analog input, peripheral function |
| Pino 53 | PF2 — PORTF bit 2, analog input, peripheral function (USB D-) |
| Pino 54 | PF3 — PORTF bit 3, analog input, peripheral function (USB D+) |
| Pino 55 | PF4 — PORTF bit 4, analog input, peripheral function |
| Pino 56 | PF5 — PORTF bit 5, analog input, peripheral function |
| Pino 57 | PF6 — PORTF bit 6, analog input, peripheral function |
| Pino 58 | PF7 — PORTF bit 7, analog input, peripheral function |
| Pino 59 | GND — Ground |
| Pino 60 | AVCC — Analog supply voltage |
| Pino 61 | PDI_DATA — Program and Debug Interface data |
| Pino 62 | PDI_CLOCK — Program and Debug Interface clock |
| Pino 63 | RESET — Reset input, active low |
| Pino 64 | VCC — Digital supply voltage |
Aplicações típicas
ATXMEGA256A3U-AU é adequado para 6 aplicaçãos: USB Human Interface Devices (HID), Building Automation Controllers, Industrial Motor Control, Smart Metering and Data Logging, LCD HMI Control Panels, IoT Sensor Hubs and Protocol Bridges.
USB Human Interface Devices (HID)
The ATXMEGA256A3U-AU is purpose-built for USB HID peripherals thanks to its integrated USB 2.0 Full-Speed device controller, which eliminates the need for an external USB PHY or bridge chip. The 32 MHz core and 32 MIPS throughput comfortably drive USB stacks alongside HID report processing at 1 kHz polling rates, while the 256 KB Flash holds USB class drivers, descriptor tables, and application firmware. The 16 KB SRAM buffers HID reports without CPU intervention thanks to the 4-channel DMA controller, and the 8-channel event system lets the USB and timer peripherals trigger one another autonomously. Place a 22-ohm source termination on D+/D- and follow the datasheet's recommended USB section layout (common-mode choke near the connector) for reliable EMI performance.
Recomendado
Building Automation Controllers
Building automation systems need 256 KB of Flash to host BACnet, KNX, or Modbus stacks plus application logic for HVAC, lighting, and access control. The ATXMEGA256A3U-AU's 34 programmable I/O lines drive relays, triacs, and 0-10V analog outputs, while the 12-bit ADC reads temperature, humidity, and occupancy sensors with 12-bit precision. The wide 2.7-3.6V supply tolerates 24V-bus-derived rails after regulation, and the XMEGA event system triggers ADC conversions from timers without CPU load. Compared to a discrete 8051 solution, the A3U delivers 2-3x more code density per MHz and runs at 1/3 the active current.
Recomendado
Industrial Motor Control
Three-phase BLDC and PMSM motor control demands high-resolution PWM, fast ADC sampling synchronized to the PWM timer, and deterministic interrupt response - all native to the ATXMEGA256A3U-AU. The 32 MHz core executes field-oriented control loops at 16 kHz with margin to spare, while the event system routes timer compare outputs directly to ADC triggers for jitter-free current sensing. The 4-channel DMA offloads commutation-table updates from the CPU, and 16 KB SRAM holds two complete control frames. Operating temperature of -40C to +85C suits industrial enclosures, and the 64-pin TQFP footprint provides ample ground and power pins for thermal dissipation at switching frequencies above 20 kHz.
Recomendado
Smart Metering and Data Logging
Electricity, water, and gas meters need low sleep current, robust Flash endurance for frequent parameter writes, and large storage for interval data. The ATXMEGA256A3U-AU provides 4 KB EEPROM with 100k+ write cycles for tariff and calibration data, 256 KB Flash for logging firmware, and the XMEGA sleep modes draw microamp-level current between measurement intervals. The 12-bit ADC with differential inputs directly samples shunt resistors for Class 1 metering accuracy, and the 8-channel event system schedules ADC, RTC, and UART wake-ups with zero CPU overhead. Real-time clock functionality through the 32.768 kHz TOSC oscillator enables accurate interval timing without external RTC chips.
Recomendado
LCD HMI Control Panels
Industrial HMI panels with segmented LCDs, keypads, and buzzer feedback fit naturally on the ATXMEGA256A3U-AU thanks to the integrated LCD controller that supports up to 40 segments without external drivers. The XMEGA core's 32 MHz speed renders menu animations and debounces 4x4 key matrices in real time, while the 4-channel DMA refreshes the LCD display RAM in the background without CPU intervention. The 256 KB Flash holds multilingual UI strings, bitmap fonts, and protocol stacks (Modbus RTU, ASCII), and the 16 KB SRAM buffers display double-buffering. The 64-pin TQFP provides 34 I/O lines for keypad scanning, status LEDs, and RS-485 transceivers.
Recomendado
IoT Sensor Hubs and Protocol Bridges
The ATXMEGA256A3U-AU bridges multiple sensor buses - I2C sensors, SPI peripherals, UART GPS modules, and analog inputs - into a unified USB or UART uplink to a host processor or cloud gateway. The rich peripheral mix (4 USART, 2 SPI, 2 TWI) allows simultaneous sensor aggregation without external muxes, and the 256 KB Flash holds TinyXML/JSON parsers, MQTT-SN, or proprietary sensor fusion code. The 4-channel DMA streams sensor data into SRAM while the CPU runs higher-level processing, and the event system lets sensor-ready interrupts trigger DMA without firmware polling. The wide 2.7-3.6V supply runs directly from a single Li-ion cell after regulation.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para ATXMEGA256A3U-AU — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | ATXMEGA256A3U-AUR | ATXMEGA192A3U-AU | ATXMEGA128A3U-AU | ATXMEGA64A3U-AU | ATXMEGA256A3U-ANR |
|---|---|---|---|---|---|---|
| Package | 64-TQFP (14x14 mm) | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same | 64-TQFP (14x14 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Flash | 256 KB | 256 KB | 192 KB (-25%) | 128 KB (-50%) | 64 KB (-75%) | 256 KB |
| SRAM | 16 KB | 16 KB | 16 KB | 16 KB | 16 KB | 16 KB |
| EEPROM | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB | 4 KB |
| USB 2.0 FS Device | Yes | Yes | Yes | Yes | Yes | Yes |
| Maximum Clock | 32 MHz (32 MIPS) | 32 MHz | 32 MHz | 32 MHz | 32 MHz | 32 MHz |
| Supply Voltage | 2.7-3.6 V | 2.7-3.6 V | 2.7-3.6 V | 2.7-3.6 V | 2.7-3.6 V | 2.7-3.6 V |
Principais diferenciais
- Largest Flash in the XMEGA A3U TQFP-64 family (vs ATXMEGA192A3U-AU)
- Integrated USB 2.0 Full-Speed device controller (vs ATXMEGA256A3-AU)
- 8/16-bit Harvard architecture with 32 MIPS throughput (vs ATMEGA2560-16AU)
- 4-channel DMA + 8-channel event system (vs ATMEGA328P-AUR)
Notas de projeto
Place a 100 nF ceramic decoupling capacitor as close as possible to each VCC/AVCC pin (pins 1, 20, 30, 40, 50, 60, 64), plus a single 10 uF bulk capacitor at the supply entry point. The XMEGA AU manual recommends separate analog and digital ground planes joined at a single point near the AVCC pin to avoid digital switching noise coupling into ADC measurements. For USB applications, route D+/D- (PF2/PF3) as a 90-ohm differential pair with a common-mode choke near the connector and ESD protection diode array (e.g., USBLC6-2SC6). Estimated decoupling budget: 7x 100 nF + 1x 10 uF = roughly 0.5 USD BOM cost.
The 64-pin TQFP package has a typical thermal resistance of approximately 50 C/W (theta_JA) for a standard 4-layer JEDEC test board. At maximum 32 MHz active current of approximately 14 mA from 3.3 V, the MCU dissipates roughly 46 mW of internal power, producing a junction-temperature rise of only 2-3 C above ambient. For closed-enclosure industrial designs, ensure ambient stays below 70 C to keep Tj below the 85 C industrial limit. In USB bus-powered designs where the MCU draws up to 100 mA from VBUS, internal dissipation rises to 330 mW and case temperature may rise 15-20 C above ambient - verify with a thermal probe in the final enclosure.
Route the PDI (PDI_DATA on pin 61, PDI_CLOCK on pin 62) signals to a dedicated 2x5 0.1-inch header or pogo-pin footprint for in-circuit programming and on-chip debug. The PDI clock can tolerate up to 10 MHz but typical AVR Studio programming uses 1-2 MHz; keep traces short (under 50 mm) and avoid running them parallel to switching signals like PWM outputs or the USB D+/D- pair. The RESET pin (pin 63) requires a 10 kohm pull-up to VCC; do not leave it floating during normal operation, or the MCU may intermittently enter programming mode. Place a 100 nF cap on RESET to ground for noise immunity.
Do not exceed VCC of 3.6 V - the ATXMEGA256A3U-AU is NOT 5 V tolerant on any pin, including the ADC inputs. The minimum VIH of 2.0 V at VCC > 2.7 V (per AVR1020 app note doc8416) means you cannot directly interface 5 V logic without a level shifter (e.g., TXS0108E or ADG3308). When migrating from the non-U ATXMEGA256A3 to the A3U variant, verify that PF2/PF3 are configured for USB only and not as GPIO - accidentally driving them as outputs will conflict with the USB peripheral. Estimated: level-shifters add 0.20-0.50 USD BOM cost and 50-150 mm2 PCB area.
When using the 12-bit ADC at the maximum 2 MSPS sample rate, add a small RC filter (typically 100 ohm + 1 nF) on each analog input to limit broadband noise and prevent fold-back from the sampling capacitor. For 50/60 Hz mains-frequency rejection, trigger ADC conversions from the event system synchronized to the 32.768 kHz TOSC, providing oversampling and decimation to achieve 16-bit effective resolution. The ADC reference can be the internal 1.0 V bandgap (drift ~5 mV/C), the internal AVCC scaled reference, or an external VREF pin - choose the external reference for absolute accuracy better than 1% across temperature.
Informações de conformidade
RoHS compliant per Microchip product page. Industrial temperature grade (-40C to +85C). Not AEC-Q100 qualified - this part targets industrial/consumer rather than automotive. Halogen-free status not explicitly documented in verified data.
