ATSAM3S1CA-AU - 64MHz ARM Cortex-M3 MCU, 64KB Flash | Microchip
MPN: ATSAM3S1CA-AU β Active| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
ATSAM3S1CA-AU Overview
A microcontroller (MCU) is a single integrated circuit that combines a processor core, memory, and peripherals into one chip, forming the lowest tier of the embedded computing hierarchy (MCU -> embedded processor -> SoC -> application processor). The SAM3S family is based on the ARM Cortex-M3 RISC processor architecture, a widely adopted 32-bit core optimized for deterministic, low-power embedded control. Originally introduced by Atmel Corporation and now manufactured by Microchip Technology after its 2017 acquisition of Atmel, the SAM3S line targets cost-sensitive industrial and consumer designs.
Key features include the 64 MHz Cortex-M3 core with nested vectored interrupt controller, 64 KB flash memory with in-system programming capability, and a rich peripheral set spanning EBI/EMI external bus interfaces, I2C (TWI), SPI, SSC (synchronous serial controller), UART/USART, USB 2.0 full-speed device, and memory card interfaces. The device provides 47 general-purpose I/O lines and operates from a 1.8V/3.3V supply domain, with the core supply specified at 1.08V to 1.32V according to distributor datasheet summaries. Industrial temperature grade options support demanding environments.
Architecturally, the Cortex-M3 core uses a Harvard bus structure with a three-stage pipeline and Thumb-2 instruction set, delivering efficient code density and interrupt latency. The flash accelerator prefetches instructions to keep the 64 MHz core fed from single-cycle-access flash, while the multi-layer bus matrix allows peripheral DMA transfers without CPU intervention.
Typical applications include industrial automation and control panels, USB-connected embedded devices and data loggers, and consumer appliance interfaces, where a balanced mix of serial connectivity, moderate compute performance, and flash expandability across the SAM3S family is required.
A key design consideration is supply-domain management: the core runs from an on-chip regulator fed by the 3.3V I/O supply, so decoupling and sequencing must follow the manufacturer datasheet recommendations, and pin compatibility across SAM3S flash-size variants should be verified against the pin configuration section before PCB reuse.
This page synthesizes distributor inventory data, datasheet summaries, and family drop-in alternatives not consolidated in any single manufacturer document.
Drop-in alternatives for ATSAM3S1CA-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 ATSAM3S1CA-AU (same form factor and footprint) β differing in SRAM, Core Processor, Package, Flash Memory, I/O Supply Voltage.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATSAM3S2CA-AU
β Drop-Inβ In Stock
$4.25 / Unit
View Datasheet βATSAM3S4CA-AU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3S8CA-AU
β Drop-Inπ Reference alternative (not in catalog)
ATSAM3S1CA-CU
β Drop-Inβ In Stock
$3.05 / Unit
View Datasheet βATSAM3S1CA-AU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 |
| Core Size | 32-Bit |
| Maximum Clock Speed | 64 MHz |
| Flash Program Memory | 64 KB (64K x 8) |
| SRAM | 16 KB |
| Core Supply Voltage | 1.08 V to 1.32 V |
| I/O Supply Voltage | 1.8 V / 3.3 V |
| Number of I/O | 47 |
| Connectivity | EBI/EMI, I2C, Memory Card, SPI, SSC, UART/USART, USB |
| Package | 100-LQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| Terminal Form | Gull Wing |
| Package Shape | Square (LFQFP) |
| Temperature Grade | Industrial |
| Lifecycle Status | Active |
ATSAM3S1CA-AU square (lfqfp) Pin Configuration Guide
Pin configuration for ATSAM3S1CA-AU (square (lfqfp) 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 ATSAM3S1CA-AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3S1CA-AU is suitable for 6 applications: Industrial Automation and Control, USB Embedded Devices, Data Loggers and Memory Card Interfaces, Consumer Appliance Interfaces, Sensor Hubs and IoT Edge Nodes, Motor Control and Power Supervision Panels.
Industrial Automation and Control
The ATSAM3S1CA-AU fits factory automation nodes such as sensor hubs, relay controllers, and HMI front ends because its 64 MHz Cortex-M3 core provides deterministic interrupt latency via the nested vectored interrupt controller, while the SSC and multiple UART/USART ports handle industrial serial links. The 47 general-purpose I/O lines in the 100-pin LQFP allow direct driving of status LEDs, keypads, and optocoupled inputs without glue logic. The EBI/EMI external bus interface extends memory or parallel-attached peripherals when 16 KB of on-chip SRAM is insufficient. Operation from a 3.3 V I/O domain simplifies integration with standard industrial logic levels, and the industrial temperature grade suits panel-mounted electronics.
Recommended
USB Embedded Devices
With its integrated USB 2.0 full-speed device controller, the ATSAM3S1CA-AU is well suited to USB-connected instruments, custom HID devices, and USB virtual-COM-port data loggers. The 12 Mbps full-speed link is handled by dedicated hardware, offloading the 64 MHz Cortex-M3 core for protocol processing and application tasks. The 64 KB flash accommodates a USB CDC stack plus a compact application, and the flash accelerator sustains execution throughput during interrupt-heavy transfers. The 100-pin LQFP exposes the USB D+/D- pins alongside 47 GPIOs for periphery such as status indicators and configuration DIP switches. Atmel/Microchip USB application notes provide reference stacks for HID, CDC, and mass-storage classes on the SAM3S family.
Recommended
Data Loggers and Memory Card Interfaces
The ATSAM3S1CA-AU includes a dedicated memory card interface (MMC/SD controller) alongside SPI and SSC peripherals, making it a strong fit for portable and standalone data loggers that write sensor records to SD media. The 64 MHz core with Thumb-2 code density executes FAT filesystem layers comfortably within the 64 KB flash for basic logging schemes, while the 16 KB SRAM buffers sector writes to reduce card write fragmentation. The EBI/EMI interface allows external SRAM expansion when buffering larger bursts. Industrial temperature grade supports loggers deployed in uncontrolled environments such as utility cabinets, and the 100-LQFP gull-wing terminals support reliable reflow assembly on 2-4 layer PCBs.
Recommended
Consumer Appliance Interfaces
Appliance control panels, small displays, and user-interface boards benefit from the ATSAM3S1CA-AU's balance of compute, I/O count, and cost. The 47 GPIO lines can drive segment LCD backends via external drivers or support matrix keypads and rotary encoders with timer capture. UART/USART and TWI (I2C) ports communicate with display drivers, EEPROM configuration stores, and main appliance controllers. Running from a single 3.3 V rail with a low core voltage of 1.08 V to 1.32 V regulated on-chip, the device keeps external power-tree design simple in cost-driven consumer boards. The 14x14 mm 100-LQFP package fits standard reflow assembly lines and offers hand-solderable 0.5 mm pitch gull-wing leads for rework.
Recommended
Sensor Hubs and IoT Edge Nodes
The ATSAM3S1CA-AU serves as a sensor hub in IoT edge nodes, aggregating data from SPI and I2C sensors before forwarding over UART, USB, or an external radio module connected via USART. The multi-layer bus matrix allows DMA-driven sensor reads that keep the 64 MHz Cortex-M3 core free for filtering and protocol formatting. The EBI/EMI interface can attach external parallel sensors or memory-mapped radios where needed. With a core supply of 1.08 V to 1.32 V and configurable clock gating across the SAM3S peripheral set, sleep currents support battery-backed nodes. The industrial temperature grade and 100-pin LQFP with 47 GPIOs provide connectivity margin for mixed sensor topologies on one controller.
Recommended
Motor Control and Power Supervision Panels
In motor-driven systems, the ATSAM3S1CA-AU acts as the supervisory controller issuing setpoints over SPI or UART to dedicated motor driver chips while reading encoders and protection feedback. The SSC provides synchronous serial links to audio-class or precision peripherals, and timer peripherals (per the SAM3S family peripheral set) support PWM generation for basic drive scenarios. The 64 MHz core executes protection algorithms such as overcurrent detection loops with predictable latency. Its EBI/EMI interface allows expansion memory for parameter tables in multi-axis setups. The 100-LQFP industrial-grade package withstands control-cabinet ambient conditions, and 47 I/O lines accommodate contactor interlocks, limit switches, and status signaling without additional logic devices.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3S1CA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3S2CA-AU | ATSAM3S4CA-AU | ATSAM3S8CA-AU | ATSAM3S1CA-CU |
|---|---|---|---|---|---|
| Package | 100-LQFP (14x14 mm) | 100-LQFP (14x14 mm) - same | 100-LQFP (14x14 mm) - same | 100-LQFP (14x14 mm) - same | 100-LQFP (14x14 mm) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) |
| Core / Clock | ARM Cortex-M3, 64 MHz | ARM Cortex-M3, 64 MHz | ARM Cortex-M3, 64 MHz | ARM Cortex-M3, 64 MHz | ARM Cortex-M3, 64 MHz |
| Flash Memory | 64 KB | 128 KB | 256 KB | 512 KB | 64 KB |
| Connectivity | EBI/EMI, I2C, Memory Card, SPI, SSC, UART/USART, USB | Identical peripheral set | Identical peripheral set | Identical peripheral set | Identical peripheral set |
| Core Supply Voltage | 1.08 V to 1.32 V | 1.08 V to 1.32 V | 1.08 V to 1.32 V | 1.08 V to 1.32 V | 1.08 V to 1.32 V |
| I/O Count | 47 | 47 | 47 | 47 | 47 |
| Temperature Grade / Suffix | Industrial (-AU) | Industrial (-AU) | Industrial (-AU) | Industrial (-AU) | Commercial (-CU) |
Key Differentiators
- Lowest-flash entry point of the 100-pin SAM3S line (vs ATSAM3S2CA-AU)
- Identical footprint across the entire SAM3S CA family (vs ATSAM3S8CA-AU)
- Industrial temperature grade in base suffix (vs ATSAM3S1CA-CU)
Design Notes
The ATSAM3S1CA-AU uses a dual-domain power architecture: VDDIO supports 1.8 V or 3.3 V operation, while the internal core is regulated to 1.08 V to 1.32 V by an on-chip regulator fed from VDDCORE/VDDIN. Place 100 nF ceramic decoupling capacitors at each supply pin pair plus one bulk 4.7 uF to 10 uF capacitor per domain, as close to the pins as possible. Never drive VDDCORE externally unless the datasheet variant explicitly permits it; on the standard part the core regulator output requires only its decoupling capacitor.
The 100-LQFP (14x14 mm) has a 0.5 mm lead pitch requiring fine-pitch soldering: specify a 0.15 mm to 0.18 mm stencil aperture reduction and reflow profile per the solder paste datasheet. Route the USB D+/D- pair as a 90-ohm differential pair with length matching under 1 mm and keep the pair away from the 18.432 MHz or other crystal lines. Provide a solid, unbroken ground plane under the MCU region; do not split planes beneath the EBI/EMI bus, which can switch all 16+ data/address lines simultaneously.
Three frequent mistakes with SAM3S designs: (1) flash-size overflow - the 64 KB flash fills quickly once a USB stack and bootloader are added; check the .map file and consider ordering ATSAM3S2CA-AU/ATSAM3S4CA-AU on the same footprint as insurance. (2) Crystal startup - the slow-clock 32.768 kHz oscillator needs correct load capacitors; wrong values cause RTC drift. (3) Pin-multiplexing conflicts - most of the 47 I/O pins are multiplexed; verify the PIO controller's peripheral-select assignment against the datasheet multiplexing table before finalizing routing, since conflicts often surface only at layout review.
Compliance Information
Compliance data was not present in the verified web data for ATSAM3S1CA-AU. The -AU suffix conventionally denotes lead-free/industrial grading for this family, but RoHS/REACH status must be confirmed on the official Microchip product page.