0013 MPSTPU(M.2 E) EN

Keywords

Raspberry Pi 5, PCIe, TPU, DTPU, Driver installation, Operation demonstration, AI, google, Coral, 2230, 2242, 2280, NVMe SSD, SSD X1

I. Introduction

The Coral M.2 Accelerator is an M.2 sized module that can expand edge TPU coprocessing capabilities via the PCIE interface for platforms such as the Raspberry Pi. Our MPSTPU expansion board adds two PCIe interfaces via a PCIe Switch, One is an M.2 E key interface, which can be used to connect a TPU module with an A+E Key interface, the other is an M.2 M key interface, which can be used to connect an NVMe SSD. The MPSTPU expansion board can provide the system with massive SSD storage while adding TPU edge computing capabilities.

II. Hardware Resources

1. Designed for the Raspberry Pi 5, it uses a 16-pin FPC to connect to the Raspberry Pi 5's PCIe interface.

2. The MPSTPU expansion board adds two PCIe interfaces via a PCIe Switch.

3. One PCIe extension M.2 E key interface, used for connecting the Google Coral Edge TPU, with the official Raspberry Pi OS loading the driver.

4. One PCIe expanded M.2 M key slot, for connecting NVMe SSD (PCIe X1, Gen2 mode only). Supports 2230/2242/2280 size SSDs (defaulting to welded mounting posts for 2280 size).

5. The SSD can be used for data storage and system booting. When booting from the SSD, the Raspberry Pi official firmware needs to be version 2024.5.13 or later.

6. The 40-pin GPIO section adopts an unobstructed design on the top. It can be connected via DuPont cable, without affecting the use of the Raspberry Pi 5's own GPIO pins.

7. Gold immersion PCB process, lead-free production, certified by UL, compliant with ROHS standards, and has a fire rating of 94V-0.

Note:

1. After the Raspberry Pi 5 firmware update, the settings cannot be modified, or else the firmware will automatically revert to the old version.

2. Due to the limitations of the switch, PCIe only supports X1 Gen2, with SSD speeds of approximately 400 MB/s.

III. System flashing and setting

3.1 概述

This document uses the Raspberry Pi OS, Ubuntu system and OpenWrt system for testing.

The version of the Raspberry Pi OS is: 2024-07-04-raspios-bookworm-arm64.img.xz

You can download the Raspberry Pi OS in:

https://www.raspberrypi.com/software/operating-systems/#raspberry-pi-os-64-bit

The version of the Ubuntu system is: ubuntu-24.04-preinstalled-desktop-arm64+raspi.img.xz

You can download the Ubuntu system in:

https://ubuntu.com/download/raspberry-pi

The version of the OpenWrt system is: openwrt-bcm27xx-bcm2712-rpi-5-squashfs-sysupgrade-linux-6.1.100-20240805.img.gz

3.2 System flashed onto the SD (TF) card

Click here to read the instructions for System flashing

3.3 System flashed onto the SSD

Click here to read the instructions for System flashing

IV. Run the TPU module

This chapter introduces how to run the TPU module on Raspberry Pi OS.

The steps in this chapter apply to both systems booting from TF card and from SSD.

4.1 Config config.txt

After the system boots, open the Raspberry Pi terminal and enter the command:

sudo nano /boot/firmware/config.txt

Or:

sudo mousepad /boot/firmware/config.txt

Add the codes in the ending of this file:

dtparam=pciex1

kernel=kernel8.img

dtoverlay=pineboards-hat-ai

Then, save the file and reboot the system:

sudo reboot

4.2 Ensuring software environment

After reboot the system, open the Raspberry Pi terminal and enter the command:

uname -r

After ensuring the kernel version is greater than 4.18, enter:

lsmod | grep apex

Ensure there is no output, then you can begin installing the TPU driver.

4.3 Install necessary software

Ensure the network is connected to internet connection to the regions out of China (you may need to find your own method), and then add the Google TPU software library:

echo "deb https://packages.cloud.google.com/apt coral-edgetpu-stable main" | sudo tee /etc/apt/sources.list.d/coral-edgetpu.list

curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

Update the software list after adding:

sudo apt-get update

Install the necessary software after the update is completed:

sudo apt-get install cmake libedgetpu1-std devscripts debhelper dkms dh-dkms

4.4 Install Gasket Driver

Enter the following commands in sequence to install the Gasket Driver:

git clone https://github.com/google/gasket-driver.git

cd gasket-driver

sudo debuild -us -uc -tc -b

cd ..

sudo dpkg -i gasket-dkms_1.0-18_all.deb

After the installation is complete, enter the following command to ensure that the driver and software were installed successfully:

sudo apt-get install gasket-dkms libedgetpu1-std

Then, add a udev rule to obtain device operation permissions:

sudo sh -c "echo 'SUBSYSTEM==\"apex\", MODE=\"0660\", GROUP=\"apex\"' >> /etc/udev/rules.d/65-apex.rules"

add user to apex:

sudo groupadd apex

sudo adduser $USER apex

Reboot the system after the setup is complete:

sudo reboot

4.5 Verification module testing and driver installation

After system starting, verification module testing and driver installation:

lspci -nn | grep 089a

Here, you need to see the TPU module, as shown in the following figure (specific parameter display is subject to the actual device):

ls /dev/apex_0

This board has a single TPU onboard, so you can see a TPU module:

By entering sudo lspci -v, you can see the driver loading, this must include the TPU driver, and if an SSD is inserted, it also needs to include the SSD module, as shown in the following figure:

4.6 代码运行环境配置

Google TPU模块代码运行需要在Python3.6-3.9之间，而树莓派最新系统的Python版本为3.11，因此我们需要使用Pyenv来下载老版本Python。

首先进行依赖安装：

sudo apt-get install -y make build-essential libssl-dev zlib1g-dev \libbz2-dev libreadline-dev libsqlite3-dev wget curl llvm libncurses5-dev \libncursesw5-dev xz-utils tk-dev libffi-dev liblzma-dev python3-openssl