Overview
The Walnut Pi CM2 is a compact system-on-module engineered around the Allwinner T527 processor, packaging an octa-core Arm Cortex-A55 central processing cluster, an auxiliary E906 RISC-V coprocessor, a 600 MHz HiFi4 audio DSP, and an integrated 2 TOPS neural processing unit into a standard 55 by 40 mm footprint. Built on a multi-layer surface-mount printed circuit board with dual 100-pin high-density board-to-board connectors, the module integrates essential peripheral circuitry directly on-package, including a Gigabit Ethernet physical transceiver and an AW869 wireless module providing dual-band Wi-Fi 6 and Bluetooth 5.0 through an onboard ceramic antenna. Storage and boot configurations leverage solid-state eMMC flash alongside an 8 MB SPI flash, operating from a standard 5V/2A direct-current supply rail.
From an acoustic and thermal perspective, the CM2 functions entirely silently with zero moving parts, relying on natural convection and carrier-board conduction for thermal dissipation under baseline operating envelopes. While its power-efficient Cortex-A55 cores maintain modest idle draw, continuous concurrent workloads involving the Mali-G57 GPU and neural acceleration engine will require passive heatsink integration to avoid thermal throttling during sustained edge inference.
In practical deployment, the module serves as a specialized edge-computing solution rather than a seamless drop-in Raspberry Pi Compute Module 5 replacement. While physically mirroring the dual-connector CM5 footprint, its pinout provides only partial electrical compatibility, and high-speed input/output is constrained by hardware multiplexing between the single-lane PCIe Gen2 bus and USB 3.0. Software maintenance depends on Debian 12-based Walnut Pi OS, Ubuntu, and Android vendor board support packages rather than official Raspberry Pi OS, establishing a platform best suited for embedded integrators who value built-in hardware acceleration over broad ecosystem plug-and-play parity.
Technical Specifications
| SoC | Allwinner T527 |
| CPU Architecture | Octa-core Arm Cortex-A55 (4x 1.80 GHz + 4x 1.42 GHz) |
| Coprocessor | E906 RISC-V core up to 200 MHz |
| Digital Signal Processor | 600 MHz HiFi4 Audio DSP |
| GPU | Arm Mali-G57 MC1 (OpenGL ES 3.2, OpenCL 2.2, Vulkan 1.3) |
| NPU | 2 TOPS Neural Processing Unit |
| System Memory | 1 GB, 2 GB, or 4 GB LPDDR4 |
| Onboard Storage | Optional 16 GB eMMC (hardware provisions for 32 GB, 64 GB, 128 GB), 8 MB SPI flash |
| Networking | On-module Gigabit Ethernet PHY, Dual-band 802.11ax Wi-Fi 6 and Bluetooth 5.0 (AW869 with onboard ceramic antenna) |
| Board Interconnect | 2x 100-pin high-density board-to-board connectors |
| Display Interfaces | HDMI up to 4Kp60, 4-lane MIPI DSI up to 1080p60 |
| Camera Interface | 4-lane MIPI CSI |
| Audio Interfaces | HPOUT speaker output, 2x microphone interfaces |
| USB Support | 1x USB 3.0, 3x USB 2.0 |
| Expansion Bus | PCIe Gen2 x1 (multiplexed with USB 3.0) |
| General I/O | GPIO, Infrared Rx, User key, BOOT, UART debug |
| Power Input | 5V/2A DC |
| Physical Dimensions | 55 x 40 mm |
| Weight | 9.6 g |
| Supported Operating Systems | Debian 12-based Walnut Pi OS, Ubuntu, Android, Home Assistant |
- Integrated 2 TOPS NPU and dedicated HiFi4 audio DSP for edge machine learning workloads
- On-module Gigabit Ethernet PHY and Wi-Fi 6/Bluetooth 5.0 with integrated ceramic antenna
- Heterogeneous computing architecture combining an 8-core CPU cluster with an auxiliary RISC-V core
- PCIe Gen2 x1 interface is hardware-multiplexed with USB 3.0, preventing concurrent utilization
- Only partial electrical compatibility with Raspberry Pi CM5 carrier boards and unsupported by official Raspberry Pi OS
- Lower overall CPU compute performance compared to Cortex-A76-based compute modules