Android: Failed to open port: No enum constant app.tauri.serialplugin.models.DataBits.8

[FalsePsyche]

When attempting to connect to a serial port on Android using the latest main branch of tauri-plugin-serialplugin, the connection fails with the error Plugin error: Failed to open port: No enum constant app.tauri.serialplugin.models.DataBits.8. This occurs when specifying 8 data bits, which is a standard configuration.

Environment:

• Plugin Version: main branch (commit around early June 2025, e.g., 81730a5 or latest)
• Tauri Version: tauri-cli 2.5.0
• Operating System: Android Go 15
• Device: Lenovo M8 Android Tablet with CP2104 USB-to-UART bridge
• Rust Version: rustc 1.86.0 (05f9846f8 2025-03-31)

Steps to Reproduce:

1. Configure tauri-plugin-serialplugin in Cargo.toml to use the main branch:

   tauri-plugin-serialplugin = { git = "https://github.com/s00d/tauri-plugin-serialplugin.git", branch = "main" }

2. Attempt to open a serial port connection from the Tauri frontend on an Android device with the following parameters (or similar standard parameters):
   • path: (e.g., /dev/bus/usb/001/011)
   • baudRate: (e.g., 115200 or any other valid rate)
   • dataBits: 8
   • stopBits: 1
   • parity: none
   • flowControl: none (or hardware if applicable, the error seems to occur before flow control is deeply engaged)
3. Observe the error.

Expected Behavior:
The serial port should connect successfully, allowing for data transmission.

Actual Behavior:
The connection fails, and the following error is logged in the Tauri console:

Error connecting to port: Plugin error: Failed to open port: No enum constant app.tauri.serialplugin.models.DataBits.8

(Referenced from frontend log: File: http://tauri.localhost/src/components/SerialPort/SerialPort2.tsx - Line 164 - Msg: Error connecting to port: Plugin error: Failed to open port: No enum constant app.tauri.serialplugin.models.DataBits.8)

Additional Context:

• The issue seems specific to the Android implementation of the plugin.
• The USB device being connected to is a CP2104 USB to UART Bridge Controller.

Log Snippet (from Tauri console on Android):

06-05 15:27:05.680 13526 13526 I Tauri/Console: File: http://tauri.localhost/src/components/SerialPort/SerialPort2.tsx - Line 91 - Msg: Raw response from available_ports: {"/dev/bus/usb/001/011":{"vid":"4292","pid":"60000","product":"CP2104 USB to UART Bridge Controller","serial_number":"02L2L7MG","type":"USB","manufacturer":"Silicon Labs"}}
06-05 15:27:05.681 13526 13526 I Tauri/Console: File: http://tauri.localhost/src/components/SerialPort/SerialPort2.tsx - Line 78 - Msg: [3:27:05 PM] INFO: Found 1 ports using standard method.
06-05 15:27:05.682 13526 13526 I Tauri/Console: File: http://tauri.localhost/src/components/SerialPort/SerialPort2.tsx - Line 100 - Msg: Port path: /dev/bus/usb/001/011
06-05 15:27:05.683 13526 13526 I Tauri/Console: File: http://tauri.localhost/src/components/SerialPort/SerialPort2.tsx - Line 101 - Msg: Port info: {"vid":"4292","pid":"60000","product":"CP2104 USB to UART Bridge Controller","serial_number":"02L2L7MG","type":"USB","manufacturer":"Silicon Labs","path":"/dev/bus/usb/001/011"}
06-05 15:27:08.504 13526 13526 I Tauri/Console: File: http://tauri.localhost/src/components/SerialPort/SerialPort2.tsx - Line 78 - Msg: [3:27:08 PM] INFO: Connecting to /dev/bus/usb/001/011...
06-05 15:27:08.657 13526 13526 E Tauri/Console: File: http://tauri.localhost/src/components/SerialPort/SerialPort2.tsx - Line 164 - Msg: Error connecting to port: Plugin error: Failed to open port: No enum constant app.tauri.serialplugin.models.DataBits.8

I'm wondering if Android will be properly supported in the future? When I pulled down the repo and manually modified it to get past this No enum constant error, I started having trouble with enabling hardware flow control. These issue lead me to assume that the android implementation is incomplete.

[s00d]

Hi, try version v2.12.0.
It's very difficult with Android — I just don't have the equipment at the moment to test how it works.

[arashi-dev]

For android, what I did was forking this repo and code the android part myself. it won't be difficult with AI. Currently it is working for me

[s00d]

For android, what I did was forking this repo and code the android part myself. it won't be difficult with AI. Currently it is working for me

You can either make a pull request or just show the code.

[arashi-dev]

You can either make a pull request or just show the code.

It's a mess actually. I wanted to but there are so much code changed even in rust and JS. it is not production ready yet! When the actual project finished, I will share the code or even pull a clean request. Until then, a help from AI won't be much different than what I currently have.

Edit: Sorry if I have not any solution to share. I will bookmark this issue and give it an update in future. I am currently working on a project which needs this library and I hope we get good result out of it.

[s00d]

You can either make a pull request or just show the code.

It's a mess actually. I wanted to but there are so much code changed even in rust and JS. it is not production ready yet! When the actual project finished, I will share the code or even pull a clean request. Until then, a help from AI won't be much different than what I currently have.

Edit: Sorry if I have not any solution to share. I will bookmark this issue and give it an update in future. I am currently working on a project which needs this library and I hope we get good result out of it.

The problem is that I have no way to test the code. Even if AI gives me something, I can't test it. All my equipment stopped working six months ago. I don't want to order new devices because the result will probably be the same as now. So, I need someone who can check and test the Android code. I’ll wait for your decision. I hope you can help.

[arashi-dev]

The problem is that I have no way to test the code. Even if AI gives me something, I can't test it. All my equipment stopped working six months ago. I don't want to order new devices because the result will probably be the same as now. So, I need someone who can check and test the Android code. I’ll wait for your decision. I hope you can help.

Alright, no worries. It's even better for us to contribute as it's gonna help this library improve faster and bring more contributors! I will share codes and be in touch with you right after I make sure my android code works stable and I get more deep in the codebase (I am almost new to rust and kotlin). Our project is quite large and is just beginning, this library will be one of the core features of our application. So I won't disappear 😅

[jonathan-nifti]

Hi! I’m in a similar situation — I’ve forked the repo and created a branch here for working on an Android fix:
https://github.com/niftitech/tauri-plugin-serialplugin/tree/android-fix

So far, I’ve managed to open a port to the device (a simple scale), but I’m still having trouble reading weights correctly. I’m testing on a Samsung Galaxy Tab.

I’ll keep you posted if I make any progress — just wanted to share in case it helps anyone. Cheers!

[s00d]

Hi! I’m in a similar situation — I’ve forked the repo and created a branch here for working on an Android fix: https://github.com/niftitech/tauri-plugin-serialplugin/tree/android-fix

So far, I’ve managed to open a port to the device (a simple scale), but I’m still having trouble reading weights correctly. I’m testing on a Samsung Galaxy Tab.

I’ll keep you posted if I make any progress — just wanted to share in case it helps anyone. Cheers!

Hi, I’ve copied your edits.