ATXMEGA256A3U-AU - 256KB Flash 32MHz 8/16-bit AVR XMEGA MCU | Microchip
Référence : ATXMEGA256A3U-AU ✓ Actif| Qté | Prix unitaire | 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 Présentation
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.
Alternatives de remplacement direct pour ATXMEGA256A3U-AU — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec ATXMEGA256A3U-AU (même facteur de forme et même empreinte) — différant par Operating Temperature, Program Memory (Flash), RoHS Status, USB Interface.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
ATXMEGA256A3U-AUR
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ATXMEGA192A3U-AU
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ATXMEGA128A3U-AU
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ATXMEGA64A3U-AU
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ATXMEGA256A3U-ANR
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
ATXMEGA256A3U-AU Valeurs maximales et caractéristiques électriques
| 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) |
| Boîtier | 64-pin TQFP (14x14 mm) |
| Température de fonctionnement | -40C to +85C (industrial) |
| Programming Interface | PDI (Program and Debug Interface) |
| Statut RoHS | Compliant |
| Type de montage | Surface Mount |
Configuration des broches de ATXMEGA256A3U-AU
| Broche 1 | VCC — Digital supply voltage (2.7-3.6 V) |
| Broche 2 | PA0 — PORTA bit 0, analog input, peripheral function |
| Broche 3 | PA1 — PORTA bit 1, analog input, peripheral function |
| Broche 4 | PA2 — PORTA bit 2, analog input, peripheral function |
| Broche 5 | PA3 — PORTA bit 3, analog input, peripheral function |
| Broche 6 | PA4 — PORTA bit 4, analog input, peripheral function |
| Broche 7 | PA5 — PORTA bit 5, analog input, peripheral function |
| Broche 8 | PA6 — PORTA bit 6, analog input, peripheral function |
| Broche 9 | PA7 — PORTA bit 7, analog input, peripheral function |
| Broche 10 | GND — Ground |
| Broche 11 | PB0 — PORTB bit 0, peripheral function |
| Broche 12 | PB1 — PORTB bit 1, peripheral function |
| Broche 13 | PB2 — PORTB bit 2, peripheral function |
| Broche 14 | PB3 — PORTB bit 3, peripheral function |
| Broche 15 | PB4 — PORTB bit 4, peripheral function |
| Broche 16 | PB5 — PORTB bit 5, peripheral function |
| Broche 17 | PB6 — PORTB bit 6, peripheral function |
| Broche 18 | PB7 — PORTB bit 7, peripheral function |
| Broche 19 | GND — Ground |
| Broche 20 | VCC — Digital supply voltage |
| Broche 21 | PC0 — PORTC bit 0, peripheral function |
| Broche 22 | PC1 — PORTC bit 1, peripheral function |
| Broche 23 | PC2 — PORTC bit 2, peripheral function |
| Broche 24 | PC3 — PORTC bit 3, peripheral function |
| Broche 25 | PC4 — PORTC bit 4, peripheral function |
| Broche 26 | PC5 — PORTC bit 5, peripheral function |
| Broche 27 | PC6 — PORTC bit 6, peripheral function |
| Broche 28 | PC7 — PORTC bit 7, peripheral function |
| Broche 29 | GND — Ground |
| Broche 30 | VCC — Digital supply voltage |
| Broche 31 | PD0 — PORTD bit 0, peripheral function |
| Broche 32 | PD1 — PORTD bit 1, peripheral function |
| Broche 33 | PD2 — PORTD bit 2, peripheral function |
| Broche 34 | PD3 — PORTD bit 3, peripheral function |
| Broche 35 | PD4 — PORTD bit 4, peripheral function |
| Broche 36 | PD5 — PORTD bit 5, peripheral function |
| Broche 37 | PD6 — PORTD bit 6, peripheral function |
| Broche 38 | PD7 — PORTD bit 7, peripheral function |
| Broche 39 | GND — Ground |
| Broche 40 | VCC — Digital supply voltage |
| Broche 41 | PE0 — PORTE bit 0, peripheral function |
| Broche 42 | PE1 — PORTE bit 1, peripheral function |
| Broche 43 | PE2 — PORTE bit 2, peripheral function |
| Broche 44 | PE3 — PORTE bit 3, peripheral function |
| Broche 45 | PE4 — PORTE bit 4, peripheral function |
| Broche 46 | PE5 — PORTE bit 5, peripheral function |
| Broche 47 | PE6 — PORTE bit 6, TOSC2, peripheral function |
| Broche 48 | PE7 — PORTE bit 7, TOSC1, peripheral function |
| Broche 49 | GND — Ground |
| Broche 50 | VCC — Digital supply voltage |
| Broche 51 | PF0 — PORTF bit 0, analog input, peripheral function |
| Broche 52 | PF1 — PORTF bit 1, analog input, peripheral function |
| Broche 53 | PF2 — PORTF bit 2, analog input, peripheral function (USB D-) |
| Broche 54 | PF3 — PORTF bit 3, analog input, peripheral function (USB D+) |
| Broche 55 | PF4 — PORTF bit 4, analog input, peripheral function |
| Broche 56 | PF5 — PORTF bit 5, analog input, peripheral function |
| Broche 57 | PF6 — PORTF bit 6, analog input, peripheral function |
| Broche 58 | PF7 — PORTF bit 7, analog input, peripheral function |
| Broche 59 | GND — Ground |
| Broche 60 | AVCC — Analog supply voltage |
| Broche 61 | PDI_DATA — Program and Debug Interface data |
| Broche 62 | PDI_CLOCK — Program and Debug Interface clock |
| Broche 63 | RESET — Reset input, active low |
| Broche 64 | VCC — Digital supply voltage |
Applications typiques
ATXMEGA256A3U-AU convient pour 6 applications: 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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
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.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour ATXMEGA256A3U-AU — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | 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 |
Principaux différenciateurs
- 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)
Notes de conception
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.
Informations de conformité
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.
