AXONS — Neural processing unit

Axon NPU is an ultra-low power neural network accelerator built for artificial intelligence (AI) and machine learning (ML) applications. It enables real-time processing while keeping power consumption to a minimum, making it perfect for IoT edge computing where battery life is critical.

Note: Axon NPU is only available in selected device variants. For more information on Axon NPU device availability, see Product overview.

The main features of Axon NPU are the following:

Fast and power efficient execution of neural network operators
End-to-end execution with little to no CPU intervention for most operators
Support for quantized int8 models.
Flexible DMA and execution pipeline that can support many functions beyond traditional neural network operators
Compatible with a software tool chain and driver that stay up to date with growing Axon NPU functionality
Acceleration of int24 DSP vector operations square root, natural log, exponent, and FFT

Optimized for battery-powered devices, Axon NPU is a high-performance yet energy-efficient solution for wearables, security systems, health monitoring, and other IoT applications. By reducing power usage, it extends system battery life without compromising processing speed, ensuring reliable performance even in resource-limited environments.

Axon NPU is intended for use with the libraries in Nordic Semiconductor device SDKs. Base operations include convolution (1D and 2D), Fully Connected, Add, Multiply, and Pooling (average and max). See the Axon NPU toolchain documentation for a complete list of limits and currently supported functionality.

Registers

Instances


Instance	Domain	Base address	TrustZone			Split access	Description
Instance	Domain	Base address	Map	Att	DMA	Split access	Description
AXONS : S AXONS : NS	GLOBAL	0x50056000 0x40056000	US	S	SA	No	Neural processing unit

Configuration


Instance	Domain	Configuration
AXONS : S AXONS : NS	GLOBAL

Register overview


Register	Offset	TZ	Description
ENABLE	0x400		Enable AXONS.
STATUS	0x404		Status

ENABLE

Address offset: 0x400

Enable AXONS.


Bit number				31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
ID																																			A
Reset 0x00000000				0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value								Description
A	RW	EN										Enable
			Disabled	0								AXONS disabled (powered off).
			Enabled	1								AXONS enabled.

STATUS

Address offset: 0x404

Status


Bit number				31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
ID																																			A
Reset 0x00000000				0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
ID	R/W	Field	Value ID	Value								Description
A	R	READY										AXONS ready
			NotReady	0								AXONS is not yet accessible
			Ready	1								AXONS is accessible