ATSAM3S2CA-AU - 64MHz Cortex-M3 MCU 128KB Flash | Microchip
MPN: ATSAM3S2CA-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.76 | $5.76 |
| 10 | $5.42 | $54.20 |
| 100 | $4.98 | $498.00 |
| 500 | $4.61 | $2,305.00 |
| 1,000 | $4.25 | $4,250.00 |
ATSAM3S2CA-AU Overview
A 32-bit microcontroller (MCU) is an integrated circuit that executes application code and controls peripherals on a single chip; the Cortex-M3 core sits within the ARM MCU hierarchy beneath higher-performance Cortex-M4/M7 parts and above 8-bit architectures. The SAM3S family targets cost-sensitive, low-power embedded systems that still need 32-bit processing headroom.
Key features include the ARM Cortex-M3 revision 2.0 core at 64 MHz with Memory Protection Unit (MPU), 128 KB single-cycle Flash and 32 KB SRAM, 47 general-purpose I/O lines on this 100-pin variant, and Flash-based program storage with in-system programming. The MRL/industrial temperature grade supports -40C to +85C operation per distributor data.
The architecture combines the three-stage Harvard Cortex-M3 pipeline with an on-chip bus matrix, allowing Flash execution while peripherals such as UARTs, timers, and USB operate concurrently. Nested Vectored Interrupt Controller (NVIC) latency is deterministic, which suits real-time embedded automation and metering firmware. Core supply operates in the 1.08 V to 1.32 V domain with an integrated regulator from a 1.8 V/3.3 V IO supply.
Typical applications include industrial control, IoT sensor nodes, motor control, metering, and low-power board designs, where the SAM3S balances cost, power, and processing throughput. Pin-to-pin compatibility with AT91SAM7S legacy parts (48- and 64-pin versions per datasheet notes) eases migration.
When designing with this device, budget Flash carefully: 128 KB is adequate for most control firmware but tight for stacks with USB host plus file systems; consider ATSAM3S4CA (256 KB) if code size may grow.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATSAM3S2CA-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 ATSAM3S2CA-AU (same form factor and footprint) β differing in Core Processor, Package, Maximum Clock Frequency, RoHS Status, SRAM.
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ATSAM3S4CA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3S8CA-AU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATSAM3S1CA-AU
β Drop-Inβ In Stock
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View Datasheet βATSAM4S2CB-ANR
β Drop-Inβ In Stock
$3.2 / Unit
View Datasheet βATSAM3S2CA-AU Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M3 revision 2.0 |
| Core Size | 32-Bit |
| Max Clock Frequency | 64 MHz |
| Flash Memory | 128 KB (128K x 8) |
| SRAM | 32 KB |
| Series | SAM3S |
| Instruction Set | Thumb-2 |
| Memory Protection Unit | Yes (MPU) |
| I/O Ports | 47 |
| Supply Voltage (VDDCORE domain) | 1.08 V to 1.32 V |
| I/O Supply | 1.8 V / 3.3 V |
| Temperature Grade | Industrial (-40C to +85C) |
| Package | 100-LQFP (14x14 mm) |
| Mounting Type | Surface Mount |
| Life Cycle Stage | ACTIVE |
| Program Memory Type | Flash |
| RoHS Status | RoHS Compliant (lead-free, 'AU' suffix) |
ATSAM3S2CA-AU 100-lqfp (14x14 mm) Pin Configuration Guide
Pin configuration for ATSAM3S2CA-AU (100-lqfp (14x14 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 ATSAM3S2CA-AU.
Refer to the datasheet for full pin configuration.
Typical Applications
ATSAM3S2CA-AU is suitable for 6 applications: Industrial Control, IoT Sensor Nodes, Metering, Motor Control, Embedded Automation & HMI Boards, Portable / Battery-Powered Devices.
Industrial Control
The ATSAM3S2CA-AU fits industrial control nodes because its 64 MHz Cortex-M3 core delivers deterministic interrupt response via the NVIC while 128 KB Flash holds protocol and control firmware. Its 47 GPIO lines and SAM3S timers interface sensors, actuators, and industrial communications directly. In a typical PLC I/O module, the MCU polls inputs, executes control loops, and drives outputs; the 32 KB SRAM supports modest buffering. Unlike 8-bit MCUs, the 32-bit core with Thumb-2 and MPU handles complex state machines at industrial -40C to +85C temperatures with single-supply 3.3 V operation.
Recommended
IoT Sensor Nodes
For IoT sensor nodes, the ATSAM3S2CA-AU balances processing headroom and power: the 64 MHz Cortex-M3 executes sampling and filtering fast, then peripherals and low-power modes let the node sleep between events. The 128 KB Flash stores sensor calibration tables, network stacks, and OTA payload slots, while 32 KB SRAM handles packet buffers. The core 1.08-1.32 V domain with on-chip regulator enables single 3.3 V battery-fed designs. A typical node reads an I2C or SPI sensor, computes statistics, and transmits via a UART/SPI radio module, with the MCU sleeping in wait mode between samples to extend battery life.
Recommended
Metering
Metering (energy, water, gas) is an explicit target application for the SAM3S family. The ATSAM3S2CA-AU samples metrology front-ends over SPI/I2C, computes consumption with its 64 MHz 32-bit core, and stores usage records in 128 KB Flash; 32 KB SRAM supports tariff tables and communication buffers. The 100-pin LQFP provides 47 I/O lines for LCD driving segments, tamper switches, and pulse outputs, while the industrial temperature grade suits outdoor meter enclosures. Because the family is pin-to-pin compatible across 64/256/512 KB Flash variants, one meter PCB can span basic and advanced firmware tiers by swapping the MCU only.
Recommended
Motor Control
The ATSAM3S2CA-AU supports basic motor control (BLDC trapezoidal, stepper, DC with Hall feedback) using SAM3S timers and PWM peripherals under its 64 MHz Cortex-M3 core. Deterministic NVIC latency ensures commutation interrupts fire on time at all loads, and 47 GPIO lines interface gate drivers, Hall sensors, and current-shunt amplifiers. Firmware for commutation, speed loops, and fault protection fits easily in 128 KB Flash. For sensorless field-oriented control with heavy trigonometric math, evaluate the Cortex-M4-based SAM4S family which adds DSP instructions; otherwise the SAM3S handles conventional motor control economically in the same footprint family.
Recommended
Embedded Automation & HMI Boards
In embedded automation panels and low-power board designs, the ATSAM3S2CA-AU acts as the main controller managing keypads, displays, relays, and serial links. Its 64 MHz core and 32 KB SRAM run an RTOS or state-machine firmware with headroom, while 128 KB Flash stores configuration and logging. The 100-pin LQFP (14x14 mm) supplies enough I/O for segment LCDs, RS-485/UART channels, and discrete I/O expansion, and the on-chip regulator allows single 3.3 V rails. Distributor listings explicitly name embedded automation as a target market; pin-compatibility with AT91SAM7S legacy parts also simplifies redesigns of existing Atmel-based panels.
Recommended
Portable / Battery-Powered Devices
The SAM3S family targets low-power board designs, making the ATSAM3S2CA-AU a fit for portable instruments, handheld meters, and data loggers. Its core operating domain of 1.08-1.32 V (from the integrated regulator off a 1.8 V/3.3 V supply) and the family's low-power wait/sleep modes let designers duty-cycle the 64 MHz core: wake on interrupt, sample, process, transmit, then sleep. 128 KB Flash retains firmware plus data tables without external memory, and 47 GPIO lines drive displays and buttons. Industrial temperature range adds robustness for field devices; the single-chip BOM (MCU plus one LDO-friendly supply) minimizes quiescent battery drain.
Recommended
Recommended Products Summary
Engineering reference data for ATSAM3S2CA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATSAM3S4CA-AU | ATSAM3S8CA-AU | ATSAM3S1CA-AU | ATSAM3S2AA-AU | ATSAM4S2CB-ANR |
|---|---|---|---|---|---|---|
| Package | 100-LQFP (14x14 mm) | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 100-LQFP (14x14) - same | 48-LQFP - different footprint | 100-pin class - verify land pattern |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 128 KB | 256 KB | 512 KB | 64 KB | 128 KB | 128 KB |
| SRAM | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB | 128 KB |
| Core | ARM Cortex-M3 @ 64 MHz | Cortex-M3 @ 64 MHz | Cortex-M3 @ 64 MHz | Cortex-M3 @ 64 MHz | Cortex-M3 @ 64 MHz | Cortex-M4 with DSP, higher clock |
| MPU (Memory Protection Unit) | Yes | Yes | Yes | Yes | Yes | Yes |
| Drop-in on ATSAM3S2CA-AU PCB | - | Yes - pin-to-pin | Yes - pin-to-pin | Yes - pin-to-pin | No - 48-pin | Verify pinout first |
Key Differentiators
- Best cost/memory balance in 100-pin SAM3S line (vs ATSAM3S4CA-AU)
- More Flash than the entry CA variant at same footprint (vs ATSAM3S1CA-AU)
- Lower cost than the Cortex-M4 SAM4S path (vs ATSAM4S2CB-ANR)
Design Notes
The SAM3S core (VDDCORE) operates in the 1.08 V to 1.32 V domain derived from VDDIN via the on-chip regulator, with VDDIO at 1.8 V or 3.3 V. Place the datasheet-specified decoupling capacitors on VDDCORE, VDDIO, and VDDIN within 2-3 mm of the pins, using short low-inductance returns to the LQFP ground pads. Do not connect an external source to VDDCORE; the internal regulator expects only its capacitor. Follow the SAM3S datasheet power sequencing requirements when VDDIO and VDDIN are supplied from separate rails.
Configure Flash wait states to match the actual system clock before raising the PLL to 64 MHz; running the core at full speed with insufficient Flash wait-state settings causes hard faults. The peripheral clock prescalers on the PMC (Power Management Controller) must be enabled explicitly for each peripheral - SAM3S peripherals are clock-gated by default after reset, a frequent cause of 'peripheral not responding' issues. Debug misbehavior with a J-Link or Atmel-ICE on the ETM/JTAG port before finalizing board bring-up.
For the 100-LQFP (14x14 mm) footprint, fan out power and ground with a dedicated ground plane and stitch the thermal pad/ground fingers with multiple vias. Route crystal traces (slow clock 32.768 kHz and main oscillator) short and shielded with local ground guard. Reserve test points on JTAG/SWD, NRSTB, and TEST pins. Because the CA package offers 79 I/O on memory-upgrade variants (ATSAM3S4CA/ATSAM3S8CA), consider connecting I/O you may use later - the footprint is shared across the family, enabling future Flash upgrades without PCB respin.
Compliance Information
The 'AU' suffix denotes lead-free, matte-tin-plated RoHS-compliant packaging per Atmel/Microchip ordering-code convention. REACH and halogen-free status not stated in provided data.