ATSAM3S8BA-AU - Cortex-M3 64MHz 512KB Flash MCU | Microchip
MPN: ATSAM3S8BA-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.89 | $7.89 |
| 10 | $7.49 | $74.90 |
| 100 | $7.1 | $710.00 |
| 500 | $6.75 | $3,375.00 |
| 1,000 | $6.4 | $6,400.00 |
ATSAM3S8BA-AU Overview
A flash microcontroller of this class integrates a processor core, program memory, SRAM, and a rich peripheral set on a single die, sitting in the hierarchy of 32-bit MCU -> ARM-based microcontroller -> embedded processor. The SAM3S family belongs to the Atmel SMART ARM-based MCU line and executes the Thumb-2 instruction set with an integrated Memory Protection Unit (MPU) for robust embedded software architectures.
Key features include the ARM Cortex-M3 revision 2.0 core at 64 MHz, 512KB (512K x 8) of flash program memory, and an integrated full-speed USB 2.0 device transceiver that enables fast data up/downloading without an external PHY. Peripheral connectivity covers I2C (TWI), SPI, UART/USART, SSC (I2S audio), IrDA, memory card (SD/MMC/SDIO), and USB, with 47 general-purpose I/O lines. Supporting peripherals include DMA, PWM, watchdog timer, brown-out detect/reset, and power-on reset.
From an architecture standpoint, the Cortex-M3 Harvard structure with Thumb-2 delivers high code density and deterministic interrupt handling via the Nested Vectored Interrupt Controller. The device operates from 1.8V, 2.5V, or 3.3V supply rails, and the family is documented as pin-to-pin compatible with the legacy Atmel AT91SAM7S series, simplifying migration for existing designs. Native Atmel QTouch capacitive touch support is available across the family.
Typical applications include USB-connected industrial instruments, human-machine interfaces with capacitive touch, motor control and power-monitoring nodes, and data-logging systems that transfer logged data over USB mass-storage or CDC classes.
A key design consideration is supply-domain planning: the device separates VDDCORE and VDDIO supplies, so designers must provide the recommended decoupling and respect the 1.62V-to-3.6V IO range when interfacing with 5V-tolerant or 1.8V logic.
This page synthesizes distributor pricing, drop-in family alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATSAM3S8BA-AU 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 ATSAM3S8BA-AU (same form factor and footprint) β differing in RoHS Status, Package, Flash Memory, Peripherals, SRAM.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
No drop-in alternatives available for this product.
Request AlternativesATSAM3S8BA-AU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 revision 2.0 |
| Core Size | 32-bit |
| Maximum Clock Speed | 64 MHz |
| Program Memory Size | 512KB (512K x 8) |
| Program Memory Type | FLASH |
| Supply Voltage | 1.8 V / 2.5 V / 3.3 V |
| Number of I/O | 47 |
| Connectivity | I2C, IrDA, Memory Card, SPI, SSC, UART/USART, USB |
| Peripherals | Brown-out Detect/Reset, DMA, I2S, POR, PWM, WDT |
| MPU | Yes (Memory Protection Unit) |
| Instruction Set | Thumb-2 |
| Package | 64-LQFP (10x10 mm) |
| Mounting Style | SMD (Surface Mount) |
| Packaging | Tray |
| Family Compatibility | Pin-to-pin compatible with AT91SAM7S series |
| Touch Support | Native Atmel QTouch capacitive touch |
| RoHS Status | Compliant (LQFP, Grn, MRL per Mouser) |
ATSAM3S8BA-AU 64-lqfp (10x10 mm) Pin Configuration Guide
Pin configuration for ATSAM3S8BA-AU (64-lqfp (10x10 mm) package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for ATSAM3S8BA-AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3S8BA-AU is suitable for 6 applications: USB Industrial Instruments, Capacitive Touch HMI, Data Logging with USB Offload, Motor Control Nodes, IoT Sensor Gateways, Portable and Battery-Powered Devices.
USB Industrial Instruments
The ATSAM3S8BA-AU fits USB-connected test and measurement instruments because its integrated full-speed USB 2.0 device transceiver removes the external PHY, cutting BOM cost and board area while providing robust EMI tolerance for factory-floor environments. Running at 64 MHz with 512KB flash, it comfortably hosts USB CDC or vendor-class firmware stacks plus command parsing and data buffering. Typical usage places the MCU as the instrument's main controller handling front-panel I/O and USB bulk transfers; unlike MCUs requiring external USB PHYs, the SAM3S needs only the D+/D- lines with appropriate series termination, and its 1.8V/2.5V/3.3V supply flexibility eases integration with industrial 3.3V logic.
Recommended
Capacitive Touch HMI
Human-machine interfaces benefit directly from the SAM3S family's native Atmel QTouch capacitive touch support: the ATSAM3S8BA-AU implements touch channels on its 47 GPIO without a dedicated touch controller, saving cost in appliances, control panels, and white-goods interfaces. The 512KB flash accommodates the QTouch library alongside graphics or menu firmware, and the Cortex-M3 at 64 MHz provides the scan-rate and response-time headroom required for multi-key, slider, and wheel widgets. Implementation typically multiplexes touch sense lines with LED drive or segment outputs; the main trade-off is scheduling touch scans around other firmware tasks, managed with the DMA and timer peripherals to keep scan timing deterministic.
Recommended
Data Logging with USB Offload
The ATSAM3S8BA-AU is a strong fit for battery-powered data loggers: its memory-card connectivity (SD/MMC/SDIO interface) writes sampled data to removable media, while the integrated USB device transceiver provides plug-and-play offload to a PC as a mass-storage or CDC device. The 512KB flash stores both application firmware and a bootloader supporting field updates via USB. In a typical design the MCU samples sensors over I2C or SPI, buffers through SRAM and DMA, and burst-writes to the card; a quantified benefit is that USB offload happens without opening the enclosure, reducing ingress-risk and service time in deployed units. Power domains must be sequenced so VBUS detect works across battery and USB sources.
Recommended
Motor Control Nodes
With four PWM-capable timer channels, DMA, and a 64 MHz Cortex-M3 core, the ATSAM3S8BA-AU serves fan, pump, and small-motor control nodes that need speed-command inputs and status reporting over USB or UART. The 47 I/O lines cover gate or driver interfaces, encoder inputs, and fault feedback, while the brown-out detector and watchdog ensure safe PWM shutdown on supply anomalies - important when controlling inductive loads. Typical usage pairs the MCU with an external gate driver or MOSFET stage; the PWM peripheral generates complementary or independent outputs with dead-time control in hardware. The main design consideration is separating the noisy power ground from the MCU analog ground to protect ADC accuracy and touch sensing.
Recommended
IoT Sensor Gateways
As a gateway aggregating I2C and SPI sensors toward a host, the ATSAM3S8BA-AU offers multiple TWI and SPI controllers plus UART/USART channels, allowing simultaneous links to several sensor buses and an upstream modem or host at 3.3V logic. The 512KB flash and SRAM hold protocol stacks (Modbus, custom frames) with margin for firmware evolution, and the SSC peripheral with I2S support handles digital microphones or audio front-ends for acoustic sensing nodes. The device's 1.62V-to-3.6V VDDIO range matches common sensor rails directly, avoiding level shifters. Designers should exploit DMA on all serial links so the 64 MHz core remains free for protocol processing and local filtering rather than byte-level servicing.
Recommended
Portable and Battery-Powered Devices
The SAM3S series is marketed for low-power benefits, and the ATSAM3S8BA-AU suits portable devices needing USB charging or data connectivity: handheld meters, readers, and accessories. The Cortex-M3 achieves high performance per clock, letting firmware finish tasks quickly and return to low-power wait modes, while supply options of 1.8V, 2.5V, and 3.3V allow direct connection to single-cell-regulated rails. In practice the USB transceiver is powered only during connection events, and wake sources (USART, TWI, RTC) keep standby current low between sessions. The key trade-off versus dedicated low-power MCUs is verifying sleep-state currents against the datasheet electrical characteristics for the specific sleep mode selected.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3S8BA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3SD8BA-AU | ATSAM3S4BA-AU | ATSAM3S2BA-AU | AT91SAM7S512D-AU |
|---|---|---|---|---|---|
| Package | 64-LQFP (10x10 mm) | 64-LQFP - same | 64-LQFP - same | 64-LQFP - same | 64-LQFP - same (pin-to-pin compatible) |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology (Atmel) |
| Core / Max Speed | ARM Cortex-M3 @ 64 MHz | ARM Cortex-M3 @ 64 MHz | ARM Cortex-M3 @ 64 MHz | ARM Cortex-M3 @ 64 MHz | ARM7TDMI @ 55 MHz |
| Flash Memory | 512KB | 512KB | 256KB | 128KB | 512KB |
| USB Device Support | Yes (integrated full-speed transceiver) | Yes (integrated transceiver) | Yes (integrated transceiver) | Yes (integrated transceiver) | Yes (USB device) |
Key Differentiators
- 512KB flash is the largest in the 64-pin SAM3S family (vs ATSAM3S4BA-AU)
- Modern Cortex-M3 core vs legacy ARM7TDMI migration path (vs AT91SAM7S512D-AU)
- Integrated USB transceiver saves external PHY (vs ATSAM3S4BA-AU)
- Trade-off: ATSAM3SD8BA-AU adds hardware SD/MMC bridge (vs ATSAM3SD8BA-AU)
Design Notes
The ATSAM3S8BA-AU uses separated supply domains: VDDCORE for the core (regulated from VDDIN via the internal regulator) and VDDIO for I/O banks. Follow the SAM3S datasheet reference schematic exactly - place the recommended output capacitor on VDDOUT and decouple every VDDIO pin with 100 nF ceramics placed within 2-3 mm of the pin. Do not power VDDCORE directly from an external rail unless you intentionally bypass the internal regulator per the datasheet's alternate configuration; incorrect core supply is the most common cause of non-boot SAM3S boards.
For the USB device interface, route D+ and D- as a 90-ohm differential pair with matched lengths, and place the series resistors and ESD protection close to the connector. The integrated transceiver means no external PHY, but the pair still should not cross plane splits. Keep the 480-ohm (as applicable per reference design) or datasheet-specified D+ pull-up handled by the MCU per USB device default. For crystal layout, keep XIN/XOUT traces short, guard with ground, and place load capacitors directly at the pins to ensure the 64 MHz PLL reference is stable from a clean 8-12 MHz crystal startup.
Three recurring SAM3S pitfalls: (1) The ERASE pin asserts full flash erase when pulled high - never leave it on a user-accessible switch without pull-down; (2) program the GPNVM bits carefully when switching boot mode to flash, since a wrong GPNVM state can brick boot until an ERASE cycle recovers it; (3) the 64-LQFP has no 5V-tolerant I/O - applying 5V logic to PA/PB pins stresses the pads, so level-shift 5V signals. Also validate that SD-card VDD is sequenced before or with VDDIO to avoid back-powering the MCU through I/O protection diodes.
If using the QTouch capacitive touch capability, allocate touch pads on a hatched ground plane with clearance per the Atmel QTouch design guide, and route sense lines away from PWM, USB, and crystal signals to prevent coupling that causes ghost key detection. Schedule touch acquisition with a timer interrupt and use the DMA to move samples so scan timing stays constant regardless of main-loop load - variable scan timing is the leading cause of inconsistent touch sensitivity in QTouch designs on Cortex-M3 SAM parts.
Compliance Information
Mouser lists the package as "LQFP, Grn, MRL" indicating green (halogen-free/RoHS) package. REACH and conflict-minerals status should be confirmed on Microchip's official compliance documentation.