FAQs for reTerminal Usage

This document contains all the frequently asked questions related to reTerminal. This will be very helpful if you are suffering from any issues when using the reTerminal.

Q1: How can I update the STM32 firmware for reTerminal LCD

Note: If your reTerminal is manufactured after 26/09/2021, the STM32 comes with V1.8 firmware pre-installed.

It is very important to make sure that you have the latest firmware flashed on to the STM32G030 chip on the reTerminal. STM32G030 is responsible to drive the LCD on the reTerminal. Updating the STM32 chip to the latest version will be helpful to solve most of the issues that you face with the reTerminal LCD.

There are 2 methods of flashing the STM32 chip.

Method 1: Directly connect to STM32 chip using the CM4 on the reTerminal and flash the firmware
Method 2: Physically connect the STM32 chip pins to the 40-Pin reTerminal GPIO using jumper wires and then use OpenOCD to flash the firmware

Method 1 works if you have the new version (v1.7 or higher) of the STM32 firmware on the reTerminal and on the other hand, method 2 is only needed if you have the old version (lower than v1.7) of the STM32 firmware on the board.

Decide Which Flashing Method to Use

Now let's go through the following steps to identify which version of the board we have so that we can choose the appropriate flashing method.

Step 1. Enter terminal window of reTerminal and type the following to open the configuration file

sudo nano /boot/config.txt

Step 2. At the very bottom of this file, comment out the line which says dtoverlay=reTerminal

#dtoverlay=reTerminal

Note: This will unload all the reTerminal drivers. So when you turn on the reTerminal next time, none of the drivers will be loaded.

Step 3. Reboot reTerminal

sudo reboot

Step 4. Make STM32 enter boot mode through i2c-tools

i2ctransfer -y 1 w2@0x45 0x9b 0x01

Step 5. List the connected I2C devices

i2cdetect -y 1

If you can see the I2C address 0x56 as the table below, you have the new version (v1.7 or higher) of the STM32 firmware on the board.

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However, if you can see the I2C address 0x45 as the table below, you have the old version (lower than v1.7) of the STM32 firmware on the board

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Step 6. Open the configuration file that we used before

sudo nano /boot/config.txt

Step 7. At the very bottom of this file, uncomment the line which says dtoverlay=reTerminal to load the drivers again

dtoverlay=reTerminal

Step 8. Power off reTerminal

sudo poweroff

Note: If you are already running STM32 v1.8 firmware, once you enter boot mode through i2c-tools, the only way to come out of boot mode is to flash the STM32 firmware.

Connect to STM32 using CM4 and flash the firmware

If you have the new version (v1.7 or higher) of the STM32 firmware on the board, please follow this method.

Step 1. Enter terminal window of reTerminal and type the following to open the configuration file

sudo nano /boot/config.txt

Step 2. At the very bottom of this file, comment out the line which says dtoverlay=reTerminal

#dtoverlay=reTerminal

Step 3. Reboot reTerminal

sudo reboot

Step 4. Make a new directory inside reTerminal

mkdir STM32

Step 5. Visit this link and download stm32flash file and the STM32G030F6_R2.bin file from the latest release version.

Note: You can click on them to start downloading

Step 6. Open command prompt on PC and navigate to the location of the downloaded files before

cd C:\Users\user\Downloads

Step 7. Transfer the files to the STM32 directory on the reTerminal we created before

scp -r .\stm32flash .\STM32G030F6_R2.bin pi@192.168.x.xx:\home\pi\STM32

Note: pi is the username and 192.168.x.xx is the IP address of reTerminal. You can replace this with hostname of reTerminal as well.

Step 8. Inside the terminal window of reTerminal, enter the STM32 directory

cd STM32

Then you will see the files that we copied earlier

Step 9. Make the flash tool executable

chmod +x stm32flash

Step 10. Make STM32 enter boot mode through i2c-tools

i2ctransfer -y 1 w2@0x45 0x9b 0x01

Step 11. Erase the flash in the STM32 chip using stm32flash tool

./stm32flash -a 0x56 -o /dev/i2c-1

Step 12. Flash the firmware to STM32 using stm32flash tool

./stm32flash -a 0x56 -w STM32G030F6_R2.bin -v -g 0x0 /dev/i2c-1

Note: STM32G030F6_R2.bin is the file name of the new firmware

Step 13. Modify the OPTR register as follows

i2ctransfer -y 1 w2@0x45 0x9b 0x00

Step 14. Open the configuration file that we used before

sudo nano /boot/config.txt

Step 15. At the very bottom of this file, uncomment the line which says dtoverlay=reTerminal

dtoverlay=reTerminal

Step 16. Reboot reTerminal

sudo reboot

Now you have successfully flashed the firmware to STM32!

Connect to STM32 using jumper wires and OpenOCD

If you have the old version (lower than v1.7) of the STM32 firmware on the board, please follow this method.

Step 1. Enter terminal window of reTerminal and type the following to update the packages list

sudo apt-get update

Step 2. Install the following packages

sudo apt-get install git autoconf libtool make pkg-config libusb-1.0-0 libusb-1.0-0-dev

Step 3. Clone the following repo and navigate to it

git clone http://openocd.zylin.com/openocd
cd openocd

Step 4. Visit this link and download the STM32G030F6_R2.bin file from the latest release version.

Note: You can click on it to start downloading

Step 5. Open command prompt on PC and navigate to the location of the downloaded files before

cd C:\Users\user\Downloads

Step 6. Transfer the files to the openocd directory on the reTerminal we created before

scp -r .\STM32G030F6_R2.bin pi@192.168.x.xx:\home\pi\openocd

Note: pi is the username and 192.168.x.xx is the IP address of reTerminal. You can replace this with hostname of reTerminal as well.

Step 7. Come back to terminal window on reterminal and enter the following inside the openocd directory

./bootstrap

Step 8. Enter the following

./configure --enable-sysfsgpio --enable-bcm2835gpio

Step 9. Compile it

make

Step 10. Install it

sudo make install

Step 11. Follow the connection below to connect the pins from STM32 to 40-Pin GPIO

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Note: The STM32 pins are located at the back of reTerminal PCBA.

Step 12. While keeping the connection, enter the following command to flash the firmware to STM32

openocd -f interface/sysfsgpio-raspberrypi.cfg -c "transport select swd" -f target/stm32g0x.cfg -c "program STM32G030F6_R2.bin verify 0x08000000;shutdown"

Note: Normally it takes about 3 seconds to finish flashing. So you need to hold the above connection for about 3 seconds until the flashing process is complete

If you see the following log, that means the STM32 firmware is successfully flashed!

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Step 13. Disconect the connections and physically disconnect the power cord directly without poweroff command

Note: If you don't physically unplug the power cord, STM32 firmware will not load successfully

Now you have successfully flashed the firmware to STM32!

Check the installed STM32G030 firmware version

Now let's check the installed STM32 firmware version

Step 1. Enter terminal window of reTerminal and type the following to open the configuration file

sudo nano /boot/config.txt

Step 2. At the very bottom of this file, comment out the line which says dtoverlay=reTerminal

#dtoverlay=reTerminal

Step 3. Reboot reTerminal
Step 4. Enter the following inside terminal window of reTerminal to check the STM32 firmware version

i2ctransfer -y 1 w1@0x45 0x97 r2

If the output looks like 0x01 0x07, that means you are using firmware version 1.7

Step 5. Open the configuration file that we used before

sudo nano /boot/config.txt

Step 6. At the very bottom of this file, uncomment the line which says dtoverlay=reTerminal

dtoverlay=reTerminal

Step 7. Reboot reTerminal

sudo reboot

Q2: How can I flash Raspberry Pi OS which is originally shipped with reTerminal?

If you have flashed to a different OS and want to switch back to the default Raspberry Pi OS which is shipped with reTerminal, you can follow the steps below

Step 1. Download the Raspberry Pi OS by visiting the links below
- 32-bit 2022-07-21-Raspbian-reTerminal
- 64-bit 2022-07-21-Raspbian-reTerminal

Note: reTerminal is originally shipped with 32-bit OS. However, you can download a 64-bit version as well

Step 2. Extract the .zip file
Step 3. Open Raspberry Pi Imager software

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Step 4. Press CTRL + SHIFT + X on the keyboard to open Advanced options window

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Here you can set a hostname, enable SSH, set a password, configure wifi, set locale settings and more

Step 5. Click CHOOSE OS and select Use custom

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Step 6. Navigate to the previously extracted image, select it and click open
Step 7. Click CHOOSE STORAGE and select the connected eMMC drive
Step 8. Finally, click WRITE

Q3: How to upgrade Raspberry Pi OS and the installed packages

We will update all the packages and also the Raspberry Pi OS to the latest version

Step 1. Open a terminal window on the reTerminal and type the following

sudo apt update
sudo apt full-upgrade

Step 2. Reinstall kernel headers

sudo apt install raspberrypi-kernel-headers

Step 3. Reboot the reTerminal

sudo reboot

Now your Raspberry Pi OS and all the necessary packages are up to update!

Q4: How can I flash OS if I replace the CM4 with non-eMMC version

If you want to use a Compute Module 4 without eMMC on the reTerminal, then you need to insert a micro-SD and flash the OS of your choice. Follow the steps below according to your operating system.

Step 1. Insert a micro-SD card to the computer using a micro-SD card reader connected to the computer, or by using a built-in card reader on a laptop
Step 2. Download Raspberry Pi Imager software by visiting this link

Note: You can choose to download for either Windows, Mac or Ubuntu

Step 3. Open Raspberry Pi Imager software

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Step 4. Press CTRL + SHIFT + X on the keyboard to open Advanced options window

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Here you can set a hostname, enable SSH, set a password, configure wifi, set locale settings and more

Step 5. Click CHOOSE OS and select your preferred OS

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NOTE: You can select OS such as 64-bit Ubuntu by navigating into Other general purpose OS

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Step 6. Click CHOOSE STORAGE and select the connected micro-sd card
Step 7. Finally, click WRITE

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Please wait a few minutes until the flashing process is complete.

Step 8. Eject the micro-SD card from computer and insert it into the reTerminal.

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Note: You need to open the shell of the reTerminal to access the micro-sd card slot

Q5: How can I log in to Raspberry Pi OS/ Ubuntu OS or other OS using a USB to serial converter

If you have a USB to Serial Converter, you can use the following steps to log in to Raspberry Pi OS

Connect jumper wires from a USB to Serial Converter to the UART pins on the 40-pin GPIO header of the reTerminal as follows

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Now let's configure the software on the computer. Please follow according to your operating system

For Windows

Step 1. Connect the USB to Serial Converter to the PC
Step 2. Open Device Manager by typing Device Manager in the windows search box
Step 3. Click on the drop-down arrow from Ports (COM & LPT) and find the name of the connected serial port (ex: COM7)

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Step 4. Download and install Putty by visiting this link

Note: Putty is an SSH and telnet client where you can use it to connect to the reTerminal via SSH. You can skip this step if you already have Putty installed

Step 5. Open Putty to connect the PC to the reTerminal
Step 6. Select Serial under the Connection Type
Step 7. Configure the settings as follows:
- Serial line: COM7 (choose your COM port)
- Speed: 9600

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Step 8. Click Open
Step 9. On the Putty window, enter the login details as follows

- Username: pi
- Password: raspberry

Step 10. If you have sucessfully logged into the Raspberry Pi OS, you will see the following output

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For Mac/Linux

Step 1. Connect the USB to Serial Converter to the PC
Step 2. Open a terminal window on Mac/Linux
Step 3. Type the following to update the packages list

sudo apt-get update

Step 4. Type the following to install minicom

sudo apt-get install minicom

Step 5. Type the following in the terminal to view the connected serial devices

dmesg | grep tty

Ex:
[ 1562.048241] cdc_acm 1-3:1.0: ttyACM0: USB ACM device

Step 6. Connect to the serial device by typing the following

minicom -D /dev/ttyACM0 -b 9600

Note: The baud rate is set to 9600

Step 7. After the hardware connections mentioned above, turn on the power from the wall power socket to power on the reTerminal

Now you have successfully logged into Raspberry Pi OS.

Q6: I cannot wake up the reTerminal LCD after sleep

Open a terminal window after connecting through SSH or VNC and enter the following commands

DISPLAY=:0 xset dpms force off
DISPLAY=:0 xset dpms force on

This will reinitialize the LCD on the reTerminal

Q7: How can I boot an OS from USB Flash Drive

You can boot an OS from USB Flash Drive by following the steps below. Here we change the boot order to USB Boot > eMMC Boot, which means, if the USB Boot fails, it will boot from eMMC.

Note: You will have to use Ubuntu or MacOS as host PC for this method.

Step 1. Remove the 4 rubber covers and open the reTerminal back shell unscrewing the 4 screws underneath

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Step 2. Remove the 2 screws to disassemble the heatsink and also the remaining 4 screws to take apart the entire case

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Step 3. Flip down the boot mode switch according to the below diagram

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Step 4. Open a Terminal window inside the Host PC after connecting to reTerminal and type the following to update the packages list

sudo apt update

Step 5. Install Git by the following command

sudo apt install git

Step 6. Git might produce an error if the date is not set properly. Type the following to correct this

sudo date MMDDhhmm

NOTE: Where MM is the month, DD is the date, and hh and mm are hours and minutes respectively.

Step 7. Clone and enter the usbboot tool repository

git clone --depth=1 https://github.com/raspberrypi/usbboot
cd usbboot

Step 8. Enter the following to install libusb

sudo apt install libusb-1.0-0-dev

Step 9. Build and install the usbboot tool

make

Step 10. Open the bootloader configuration file

sudo nano recovery/boot.conf

Step 11. Change the BOOT_ORDER field to the following

BOOT_ORDER=0xf15

Note: Here if USB Boot fails, it switches to eMMC boot

Step 12. Run the following to update the EEPROM image

cd recovery
./update-pieeprom.sh

The pieeprom.bin file is now ready to be flashed to the Compute Module 4

Step 13. Navigate back to the usbboot directory

cd ..

Step 14. Run the usbboot tool to flash the bootloader EEPROM

sudo ./rpiboot -d recovery

Step 15. Connect reTerminal to the PC via USB Type-C cable

Now it will take a few seconds to transfer the necessary files to the reTerminal.

Step 16. Turn off reTerminal, flip the Boot Mode switch back to the original position and assemble the reTerminal shell
Step 17. Connect a bootable USB Flash Drive with a suitable OS inside, connect to one of the USB Ports on the reTerminal and turn on reTerminal

Now you will see reTerminal booting from the connected USB Drive

Q8: Why there is black glue around the chips on the CM4?

We have specially applied epoxy resin underfill adhesive (which looks like black glue) around the chips on the CM4 to make sure the ICs are protected well. This also makes the whole CM4 more reliable.

Q9: Why does buzzer, LEDs and buttons do not work after installing the reTerminal drivers?

reTerminal comes equipped with 2 versions for the I/O Expansion chip. Old version with MCP23008 and new version with PCA9554. If you installed reTerminal drivers manually, please check the following.

First of all check whether which chip is installed on your reTerminal.

Open terminal window
i2cdetect -y 1

If you see 0x20 I2C address, the reTerminal is equipped with MCP23008 chip

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If you see 0x38 I2C address, the reTerminal is equipped with PCA9554 chip

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For reTerminal with MCP23008 chip, you need to do the following.

sudo nano /boot/config.txt
Add "dtoverlay=reTerminal,addr=0x20,mcp23008" at the end of the file
Ctrl + x > y > ENTER, to save and close the file
sudo reboot

For the reTerminal with the latest PCA9554 chip, you don't have to do any changes.

Q10: How can I install Ubuntu on reTerminal?

Step 1. Flash Ubuntu Server 21.10 to reTerminal eMMC storage

Note: Refer to flashing instructions here. After opening Raspberry Pi Imager, navigate to CHOOSE OS > Use custom and select the above image to flash

Step 2. SSH into reTerminal and run the following commands one after the other. Make sure to use ubuntu as the username and ubuntu as the password

wget https://files.seeedstudio.com/wiki/ReTerminal/ubuntu/script1.sh
wget https://files.seeedstudio.com/wiki/ReTerminal/ubuntu/script2.1.sh
chmod +x script1.sh script2.1.sh
sudo ./script1.sh
sudo reboot
sudo ./script2.1.sh
sudo reboot

Step 3. Now, reTerminal will boot into Ubuntu Desktop, but in wrong orientation

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Step 4. Click the power icon on top right corner and click Settings

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Step 5. Select Displays and choose Portrait Left under Orientation and click Apply

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Finally you will see the Ubuntu Desktop in proper orientation!

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Q11: The screen orientation is incorrect after installing Raspberry Pi OS Bullseye

Step 1. After flashing Raspberry Pi OS Bullseye to reTerminal eMMC, follow this guide to install the necessary drivers
Step 2. Create a new file named monitors.xml under .config directory

sudo vi ~/.config/monitors.xml

Step 3. Copy the following content into the above file to explicitly set the LCD display (DSI-1) and save the file by typing :wq after pressing ESC

<monitors version="2">
  <configuration>
    <logicalmonitor>
      <x>0</x>
      <y>0</y>
      <primary>yes</primary>
      <monitor>
        <monitorspec>
          <connector>DSI-1</connector>
          <vendor>unknown</vendor>
          <product>unknown</product>
          <serial>unknown</serial>
        </monitorspec>
        <mode>
          <width>720</width>
          <height>1280</height>
          <rate>60.000</rate>
        </mode>
      </monitor>
      <transform>
        <rotation>right</rotation>
      </transform>
    </logicalmonitor>
  </configuration>
</monitors>

Step 4. Open /boot/config.txt

sudo vi /boot/config.txt

Step 5. Add the following into the file

dtoverlay=reTerminal,tp_rotate=1

Step 6. Reboot reTerminal

sudo reboot

Now the screen will be displayed in the correct orientation!

Q12: LEDs and Buzzer do not work after installing reTerminal drivers

This issue will not last long. We will completely solve this issue later from reTerminal drivers itself

Step 1. Open /boot/config.txt

sudo vi /boot/config.txt

Step 2. Comment the following line and save the file by typing :wq after pressing ESC

#dtoverlay=reTerminal-bridge

Step 3. Reboot reTerminal

sudo reboot

Now the LEDs and Buzzer will work as normal.

Q13: How to check if the Encryption Chip is ATECC608A-SSHDA-B or ATECC608A-TNGTLSS-G

Released Date	Encryption Chip IC Version
Before 09/03/2021	ATECC608A-SSHDA-B
Sept 2021 - January 2022	ATECC608A-SSHDA-B or ATECC608A-TNGTLSS-G
After 02/01/2022	ATECC608A-TNGTLSS-G

To check which Encryption chip by type i2cdetect -y 3 command in Terminal, If you see 0x35 in the output table then the reTerminal is equipped with ATECC608A-TNGTLSS-G chip, otherwise it is equipped with ATECC608A-SSHDA-B.

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Resources

[PDF] reTerminal Schematics
[ZIP] reTerminal Schematics
[PDF] Raspberry Pi Compute Module 4 Datasheet
[Web Page] Raspberry Pi Official Documentation

Tech support

Please submit any technical issues into our forum

FAQs for reTerminal Usage

Q1: How can I update the STM32 firmware for reTerminal LCD​

Decide Which Flashing Method to Use​

Connect to STM32 using CM4 and flash the firmware​

Connect to STM32 using jumper wires and OpenOCD​

Check the installed STM32G030 firmware version​

Q2: How can I flash Raspberry Pi OS which is originally shipped with reTerminal?​

Q3: How to upgrade Raspberry Pi OS and the installed packages​

Q4: How can I flash OS if I replace the CM4 with non-eMMC version​

Q5: How can I log in to Raspberry Pi OS/ Ubuntu OS or other OS using a USB to serial converter​

For Windows​

For Mac/Linux​

Q6: I cannot wake up the reTerminal LCD after sleep​

Q7: How can I boot an OS from USB Flash Drive​

Q8: Why there is black glue around the chips on the CM4?​

Q9: Why does buzzer, LEDs and buttons do not work after installing the reTerminal drivers?​

Q10: How can I install Ubuntu on reTerminal?​

Q11: The screen orientation is incorrect after installing Raspberry Pi OS Bullseye​

Q12: LEDs and Buzzer do not work after installing reTerminal drivers​

Q13: How to check if the Encryption Chip is ATECC608A-SSHDA-B or ATECC608A-TNGTLSS-G​

Resources​