Minimum Requirements for ACK-based products

Alexa Connect Kit (ACK)-based products should meet the following minimum requirements.

Host microcontroller requirements

The following table lists host microcontroller requirements for an ACK-based device.

Category Requirement


  • Universal Asynchronous Receiver-Transmitter (UART) – Use a UART to communicate with the ACK module.
    • 115200 baud rate, 8 bit, no hardware flow control.
  • GPIOs – Two GPIOs to connect to the ACK module to handle the following:
    • Host interrupt.
    • ACK module reset.
  • (Optional) CRC32 acceleration.


  • Non-volatile memory size – 128 KB or larger.
    • A typical fully-featured ACK application code size is about 60 KB. Exact memory usage depends on supported features. Use 128 KB to support over-the-air (OTA) updates and to store both the application bootloader and two separate application images.
  • RAM – You should have 32 KB of total RAM or more.
    • 4 KB to 8 KB RAM. ~0.5KB for global data, 3 KB to 4 KB for your stack. Depending on selected features, the ACK Device SDK might require up to 12 KB of RAM.


  • Architectural requirements – You don't have to follow any specific architectural requirements. Typically, manufacturers use an Arm Cortex M0 core processor or similar.
  • Microcontroller (MCU) – A 32-bit MCU isn't a strict requirement but you must use 8-byte double-precision floating point calculations for certain Alexa smart home capabilities, such as RangeController or ColorController. You can use software emulation to achieve this.

Device requirements

The following table lists the device requirements and recommendations for an ACK-based device.

Category Requirement

User interface

  • Physical interaction – A button or mechanism to initiate device setup mode and perform a device factory reset.
  • LED (recommended) – A LED or other similar indicators to inform users of the current device state. For example, setup mode.

Size of device

  • Internal space – Provide enough internal space to accommodate your printed circuit board (PCB), the ACK module, host microcontroller unit (HMCU) and additional components (power supply, peripherals, and so on). For more details on ACK module sizes, see the specification datasheet provided from the module manufacturer. You can find the data sheets on the Resources page in the ACK developer console.
  • Device surface (recommended) – Provide a device design that accommodates the Amazon Frustration-Free Setup (FFS) inner barcode. For more details about FFS barcodes and size requirements, see Wi-Fi Simple Setup Provisionee 2D Barcode Specification.

Product certification

  • ACK modules – ACK modules are pre-certified with relevant regulatory bodies. For more details about the specific certifications, see the specification datasheet provided from the module manufacturer. You can find the data sheets on the Resources page in the ACK developer console.
  • ACK certification – You must certify your ACK-based products with the Works with Alexa (WWA) program and Frustration-Free Setup (FFS). For more details about certification, see ACK Certification.
  • External certification – Your product might require additional external certification, depending on the what you're building and where you're selling it. For more details, consult your certification and testing providers.

Product packaging

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Last updated: Nov 27, 2023