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Microchip Technology ATSAMR21E16A-MU
- Part No.:
- ATSAMR21E16A-MU
- Manufacturer:
- Microchip Technology
- Category:
- RF Transceiver ICs
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
ATSAMR21E16A-MU.pdf
- Description:
- IC RF TXRX+MCU ISM>1GHZ 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,912
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Product details
Overview
ATSAMR21E16A-MU from Microchip Technology (formerly Atmel) is a 32-bit ARM Cortex-M0+ wireless microcontroller integrating an ultra-low-power 2.4GHz ISM band transceiver, 64KB Flash, 8KB SRAM, and operating at up to 48MHz. It features a 12-bit 350ksps ADC with 4 external channels, two analog comparators, 16 programmable I/O pins, and supports SleepWalking peripherals for autonomous low-power operation in battery-powered IoT sensor nodes.
For engineers reviewing the ATSAMR21E16A-MU datasheet, ATSAMR21E16A-MU pinout, ATSAMR21E16A-MU application, or ATSAMR21E16A-MU equivalent, key selection criteria include its QFN32 package, -40°C to +85°C industrial temperature grade, integrated AT86RF233 transceiver with -99dBm RX sensitivity and +4dBm TX output, hardware AES encryption, and SERCOM-configurable USART/I²C/SPI interfaces.
Technical Context
The ATSAMR21E16A-MU implements a dual-domain clock system with DFLL48M and FDPLL96M for independent peripheral clock scaling, enabling simultaneous high-CPU-frequency operation and per-peripheral power optimization. Its Event System provides 12 asynchronous/synchronous channels for inter-peripheral signaling without CPU intervention-even in standby mode.
SleepWalking allows peripherals like the RTC, ADC, or TC to autonomously wake themselves and their clocks to perform predefined tasks (e.g., periodic sampling or threshold-triggered capture), minimizing CPU wake-ups. The integrated AT86RF233 transceiver uses O-QPSK modulation with 32-length spreading, hardware MAC acceleration (auto-ack, auto-retry), and 128-byte TX/RX frame buffering via dedicated SPI interface (SERCOM4).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| CPU Core | ARM Cortex-M0+ running at up to 48MHz; delivers 2.46 CoreMark/MHz for deterministic real-time control. |
| Memory | 64KB Flash (in-system programmable via SWD); 8KB SRAM; no serial Flash included in this variant. |
| Wireless Transceiver | Integrated AT86RF233 2.4GHz ISM transceiver: -99dBm RX sensitivity, +4dBm TX output, 250kb/s data rate, hardware AES-128. |
| Analog Peripherals | 4-channel 12-bit 350ksps ADC with programmable gain (1/2x–16x), oversampling support up to 16-bit resolution; two analog comparators with window mode. |
| Digital Interfaces | Four SERCOM modules (configurable as USART/I²C/SPI/LIN); one full-speed USB 2.0 device/host interface; 16 GPIOs with configurable pull-up/down. |
| Power & Clock | 1.8V–3.6V supply; idle/standby sleep modes; SleepWalking capability; internal 8MHz OSC8M, 48MHz DFLL48M, and 96MHz FDPLL96M. |
| Package & Temp | QFN32 (5×5 mm, 0.5 mm pitch); exposed thermal pad connected to GND; industrial grade (-40°C to +85°C). |
Pinout & Package
ATSAMR21E16A-MU is housed in a 32-pin QFN package (5×5 mm, 0.5 mm pitch) with an exposed center thermal pad internally connected to GND. The pad must be soldered to PCB ground for mechanical stability and thermal performance. Pin functions are multiplexed across PORT A only (PA00–PA31), with dedicated RF (RFP/RFN), crystal (XTAL1/XTAL2), debug (SWCLK/SWDIO), and power pins.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PA14 / PA15 | RF Differential Port (RFP / RFN) | Direct connection to integrated AT86RF233 transceiver; requires 100Ω differential impedance layout and AC coupling; DC common-mode voltage varies by state (0.9V TX, 20mV RX). |
| PA00 / PA01 | 32.768kHz Crystal Oscillator (XIN32 / XOUT32) | Supports RTC clock/calendar; not present on SAM R21E variants per datasheet Table 4-2 - these pins are reserved for future use or alternate functions. |
| PA30 / PA31 | Serial Wire Debug (SWCLK / SWDIO) | Two-pin SWD interface for non-intrusive programming and debugging; SWDIO auto-switches on debugger detection. |
| PA06 / PA07 | ADC Input Channels (AIN[6] / AIN[7]) | Single-ended or differential analog inputs supporting programmable gain and oversampling; share same VDDANA supply domain. |
| XTAL1 / XTAL2 | 16MHz RF Crystal Interface (XOSCRF) | Direct connection to AT86RF233's internal oscillator amplifier; required for transceiver timing; DC level fixed at 0.9V. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-Low-Power Wireless SoC | Combines ARM Cortex-M0+ MCU and AT86RF233 transceiver in single QFN32 package-reduces BOM count and PCB area vs discrete MCU + RF IC solutions. |
| SleepWalking Peripherals | RTC, ADC, or Timer/Counter can autonomously wake, configure clocks, execute tasks (e.g., sample sensor, compare value), and signal CPU only when result or threshold event occurs. |
| Hardware Security Engine | Dedicated AES-128 accelerator and true random number generator enable secure over-the-air firmware updates and encrypted sensor data transmission without CPU overhead. |
| Flexible Serial Connectivity | Four SERCOM modules support runtime reconfiguration as USART (full/half-duplex), I²C (up to 3.4MHz), SPI, or LIN slave-enabling interoperability with diverse sensors and host systems. |
| Event-Driven Architecture | 12-channel Event System enables zero-latency, CPU-free peripheral-to-peripheral communication (e.g., ADC trigger → TC capture → DMA transfer), reducing interrupt load and power consumption. |
Applications
| Smart Home Sensor Node | Industrial Wireless Monitor |
|---|---|
Use Scenario: Battery-powered temperature/humidity/motion sensor reporting to gateway every 5 minutes. IC Role / Device Role / Timing Role: ATSAMR21E16A-MU acts as system controller and 2.4GHz transceiver; RTC triggers periodic wake-up; SleepWalking ADC samples sensor; AT86RF233 handles MAC-layer packetization and ACK. Use Value: Achieves >5-year battery life using standby mode (200nA typical) and autonomous wakeup-no CPU involvement during sensing/transmit cycles. | Use Scenario: DIN-rail mounted vibration/temperature monitor in factory environment with RS-485 backhaul and local 2.4GHz mesh relay. IC Role / Device Role / Timing Role: ATSAMR21E16A-MU serves as edge node controller; SERCOM configured as RS-485 UART for PLC interface; TCC generates precise PWM for status LED; TC3 captures timestamped vibration pulses. Use Value: Hardware CRC-32 and AES ensure data integrity and confidentiality across untrusted wireless links; industrial temp grade (-40°C to +85°C) guarantees reliability in harsh environments. |
| Medical Wearable Tracker | Asset Tracking Tag |
Use Scenario: Disposable skin patch monitoring heart rate and motion, transmitting encrypted biometric data to smartphone. IC Role / Device Role / Timing Role: ATSAMR21E16A-MU integrates PTC for capacitive touch UI, ADC for analog front-end, and AT86RF233 for BLE-compatible 2.4GHz transmission; WDT ensures fail-safe reset on firmware hang. Use Value: On-chip AES-128 encrypts sensitive health data before transmission; low-voltage operation (1.8V min) extends coin-cell battery life while maintaining medical-grade accuracy. | Use Scenario: GPS-denied indoor logistics tag tracking pallet location via RSSI-based triangulation using multiple gateways. IC Role / Device Role / Timing Role: ATSAMR21E16A-MU executes lightweight mesh routing logic; AT86RF233 measures RSSI of neighbor beacons; RTC maintains synchronized timebase for TDMA slotting. Use Value: Hardware-assisted MAC (auto-ack/retry) and -99dBm sensitivity enable robust multi-hop communication in noisy warehouse RF environments with minimal firmware complexity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar wireless microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ATSAMR21G16A-MU | 48-pin QFN; 28 GPIOs; 8 ADC channels; SERCOM5; no XOSC32K; identical core/peripherals/transceiver. | Requires larger PCB footprint; supports more sensors and complex I/O routing; lacks RTC crystal oscillator input. | Select when additional I/O, ADC channels, or SERCOM instances are needed-pinout and firmware are not compatible with ATSAMR21E16A-MU. |
| STM32WLE5JC | ARM Cortex-M4; LoRa/Sub-GHz + 2.4GHz dual-band; 256KB Flash; 64KB RAM; different RF architecture (SX1262 + custom PHY). | Targets long-range LPWAN (LoRaWAN) instead of short-range 2.4GHz mesh; higher power consumption in active mode; no SleepWalking peripheral autonomy. | Choose for sub-GHz coverage requirements or regulatory compliance in regions where 2.4GHz is restricted; not a drop-in replacement due to RF stack, memory, and peripheral differences. |
Compared with ATSAMR21G16A-MU, ATSAMR21E16A-MU offers smaller form factor and lower pin count at the cost of reduced I/O and ADC channel count; versus STM32WLE5JC, it delivers superior low-power autonomy via SleepWalking and tighter integration of AT86RF233 but lacks LoRa support and uses a less powerful CPU core.
Availability
ATSAMR21E16A-MU is available at Aetrix Electronics and suitable for smart home sensor nodes, industrial wireless monitors, medical wearables, asset tracking tags, and battery-powered IoT edge devices requiring stable component supply, long-term lifecycle support, and qualified industrial-grade operation.
Supply support for ATSAMR21E16A-MU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology acquired Atmel in 2016 and maintains full support for the SMART ARM-based microcontroller portfolio, including design resources, toolchains, and long-term product availability.
The SAM R21 product line was designed specifically for ultra-low-power, integrated wireless applications in constrained IoT endpoints-emphasizing SleepWalking autonomy, hardware security, and seamless migration across pin-compatible variants.
FAQ
What is the maximum operating frequency and core type of the ATSAMR21E16A-MU?
The ATSAMR21E16A-MU features an ARM Cortex-M0+ processor core rated for operation up to 48MHz. It achieves 2.46 CoreMark/MHz performance and includes a single-cycle hardware multiplier and Micro Trace Buffer (MTB) for efficient real-time debugging. This frequency is sustained across the full industrial temperature range (-40°C to +85°C) under 1.8V–3.6V supply conditions.
Does the ATSAMR21E16A-MU include an integrated radio transceiver, and what are its key RF specifications?
Yes, the ATSAMR21E16A-MU integrates the AT86RF233 2.4GHz ISM band transceiver. Key RF specs include -99dBm receiver sensitivity at 250kb/s, +4dBm maximum transmit output power, O-QPSK modulation with 32-length spreading, hardware-accelerated MAC (auto-acknowledge, auto-retry), and 128-byte TX/RX frame buffer. The transceiver connects directly to RFP/RFN pins and uses a dedicated 16MHz crystal (XTAL1/XTAL2).
What are the memory resources available on the ATSAMR21E16A-MU?
The ATSAMR21E16A-MU contains 64KB of in-system programmable Flash memory and 8KB of SRAM. Unlike the E19 variant, it does not include integrated serial Flash. The Flash supports read-while-write operation and is programmed/debugged via the two-pin Serial Wire Debug (SWD) interface. Memory mapping follows a linear address space compatible across the SAM R21 family.
How many analog-to-digital converter (ADC) channels does the ATSAMR21E16A-MU support, and what resolution options are available?
The ATSAMR21E16A-MU includes a 12-bit ADC with four external input channels (AIN[0]–AIN[3] on PA04–PA07). It supports programmable gain (1/2x to 16x), automatic offset/gain error compensation, and hardware oversampling with decimation to achieve effective resolutions of 13-, 14-, 15-, or 16-bit. Sampling rate is up to 350ksps in single-ended mode.
What debug interface does the ATSAMR21E16A-MU provide, and how is it implemented physically?
The ATSAMR21E16A-MU provides a two-pin Serial Wire Debug (SWD) interface using PA30 (SWCLK) and PA31 (SWDIO). SWDIO automatically switches from GPIO to debug function upon debugger detection (cold/hot plug). This interface supports non-intrusive on-chip debugging, flash programming, and real-time trace via the Micro Trace Buffer-enabling development without dedicated JTAG header space.
ATSAMR21E16A-MU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- SMART™ SAM R21
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- TxRx + MCU
- RF Family/Standard:
- General ISM > 1GHz
- Protocol:
- -
- Modulation:
- O-QPSK
- Frequency:
- 2.4GHz
- Data Rate (Max):
- 250kbps
- Power - Output:
- 4dBm
- Sensitivity:
- -99dBm
- Memory Size:
- 64kB Flash, 8kB SRAM
- Serial Interfaces:
- I2C, SPI, UART, USART, USB
- GPIO:
- 16
- Voltage - Supply:
- 1.8V ~ 3.6V
- Current - Receiving:
- 11.3mA ~ 11.8mA
- Current - Transmitting:
- 7.2mA ~ 13.8mA
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 32-QFN (5x5)
ATSAMR21E16A-MU FAQ
1.How can I place an order for ATSAMR21E16A-MU through Aetrix?
Please submit a Request for Quotation (RFQ) for ATSAMR21E16A-MU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ATSAMR21E16A-MU reliable?
The price and inventory of ATSAMR21E16A-MU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ATSAMR21E16A-MU is usually 5 days.
3.What payment methods are accepted for ATSAMR21E16A-MU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ATSAMR21E16A-MU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ATSAMR21E16A-MU?
ATSAMR21E16A-MU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ATSAMR21E16A-MU order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ATSAMR21E16A-MU?
For technical support, including ATSAMR21E16A-MU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ATSAMR21E16A-MU requirements.
6.How does Aetrix verify that ATSAMR21E16A-MU is sourced from the original manufacturer or authorized distributors?
All ATSAMR21E16A-MU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ATSAMR21E16A-MU meets industry standards.
7.What is the process for return or replacement of ATSAMR21E16A-MU?
All ATSAMR21E16A-MU units undergo pre-shipment inspection (PSI). If there is an issue with ATSAMR21E16A-MU, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ATSAMR21E16A-MU part is unused and in its original packaging.
Return procedure for ATSAMR21E16A-MU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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