Sample GPIO setup and use in ROSbot XL

Software
1

Hi,

Any chance you have any sample/tutorial for GPIO configuration and use in ROSbot XL?
I am under the impression that the firmware has to be modified to expose GPIOs and other pins.

2

Hi @Dhon_G,

This type of issue is very uncommon, and we don’t currently have any recorded cases of it.

That said, we’re in the final stage of a firmware refactoring, which will be officially released soon. In the meantime, you can test the latest version on ROSbot by downloading the Snap package from the jazzy/edge channel: Install rosbot on Linux | Snap Store.

For your purpose, you can also make custom modifications directly in the firmware repository: GitHub - husarion/rosbot-firmware: Unified micro-ros based firmware for ROSbot 3 and ROSbot XL for STM32F4 microcontroller. · GitHub. The project structure is relatively straightforward, so implementing GPIO-related changes should be manageable.

The rosbot-firmware repository includes tasks for building the firmware. Once built, it can be flashed using the rosbot_ros repository and the following command:

ros2 run rosbot_utils flash_firmware --robot-model <rosbot/rosbot_xl>
-f <firmware>

If you encounter any difficulties, I will try to advise you.

3

Hi @RafalGorecki ,

Thanks, will give firmware modification a shot.

I’ll be using EXT_GPIO1, EXT_GPIO2, EXT_GPIO3, and EXT_PWM1.

@Tomasz_Lejkowski provided me the corresponding STM pins for the GPIOs as follows.

EXT_GPIO1 < - > PG2
EXT_GPIO2 < - > PG3
EXT_GPIO3 < - > PG4

Are you able to provide me the corresponding STM pin for the EXT_PWM1?

4

I’m sending a screenshot, I’ll add it to rosbot-firmware in a while.

image
image680Ă—538 74.5 KB

1 Like
5

Hi @RafalGorecki ,

Do you mean you will write the code to expose these extra GPIOs and functionalities to ROS or just pin configs?

6

I’ve only added the STM32 pin names to the config. I can’t configure them because the configuration depends on how they’re to be used.

7

No worries. I tried to implement the extra GPIOs - GPIOs 1 & 2 and PWM1 as digital outputs while GPIO 3 as input. GPIO 3 will read from an encoder sensor and publish pulse count every 100ms. Are you able to review the code for me? I haven’t built or tested it yet as I’m too afraid to try. I have no experience updating a firmware before.

Here’s the link to the forked repo in case you’re open to checking: GitHub - dfavr24/rosbot-firmware: Unified micro-ros based firmware for ROSbot 3 and ROSbot XL for STM32F4 microcontroller. · GitHub

Regards,
Dhong

8

Unfortunately, I can’t verify the code’s accuracy.

Regarding flashing, the latest version of jazzy/edge adds the ability to replace the original firmware. You can replace default firmware file with your custom one.

Example:

cd /var/snap/rosbot/current/config_dir/rosbot_utils/firmware
mv rosbot-v1.0.1-jazzy.bin rosbot-v1.0.1-jazzy-backup.bin # Create buckup for rosbot firmware
cp /<path_to_firmware>/firmware.bin rosbot-v1.0.1-jazzy.bin
sudo rosbot.flash
9

No problem, thanks.

I was just wondering what would you recommend for debugging?

I managed to build and flash the edited firmware. When running micro ros agent, the topics successfully appear in the list however can’t get something to work in the actual hardware when trying to publish something in the topics.

10

Software Diagnostics
You can use debugSerial

You can monitor the debug output over USB. The device should appear with the following USB identifiers:

  • Vendor ID: 0403
  • Product ID: 6015

Any serial terminal application can be used to read the logs, for example:

  • platformio device monitor
  • minicom
  • screen
  • picocom

Serial communication parameters:

  • Baud rate: 921600
  • Data bits: 8
  • Parity: None
  • Stop bits: 1 (8-N-1 )

Example using PlatformIO:

platformio device monitor -b 921600 -p <serial_port> # e.g. /dev/ttyUSB0

Hardware Diagnostics
It is also recommended to use a logic analyzer to verify whether the electrical signals on the bus match the expected values.

11

Hi,

Thanks.

I ended up using “screen” command to debug. I’ve also confirmed electrical output from the pins using a multimeter. It turned out there’s an error with my message handle definition and an issue with my motor driver.

Thanks for all the help. I guess we can move forward from here.

Regards,
Dhong

1 Like
12

I’m glad I could help and good luck with your project

1 Like