Can't use the System.Device.I2c.Slave library for ESP32 device

[bwinklesky]

Tool

Visual Studio extension

Description

Can't use the System.Device.I2c.Slave library for ESP32 device.

The connected target does not have support for the following assembly(ies):

'System.Device.I2c.Slave'

How to reproduce

1. Add nuget package nanoFramework.System.Device.I2c.Slave to project.
2. Attempt to Deploy to ESP32 device.

Expected behaviour

No response

Screenshots

No response

Aditional context

No response

[josesimoes]

Moving to discussions as this is a support request and we don't use issues for that.

[bwinklesky]

if it's not an issue, what is the problem?

I can use the I2C master/slave on the ESP32 if using C++. Why not nanoframework?

[alberk8]

What is the ESP32 module you are using.

[bwinklesky]

Esp32 WROOM 32E

[alberk8]

which firmware is loaded?

[bwinklesky]

I’ve tried ESP32_REV0, ESP32_BLE_REV0/3

…

________________________________ From: alberk8 ***@***.***> Sent: Sunday, August 10, 2025 6:32:39 PM To: nanoframework/Home ***@***.***> Cc: Brett Winklesky ***@***.***>; Author ***@***.***> Subject: Re: [nanoframework/Home] Can't use the System.Device.I2c.Slave library for ESP32 device (Discussion #1664) which firmware is loaded? — Reply to this email directly, view it on GitHub<#1664 (reply in thread)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ALE7XFWWLXKYMZX2LW5CRK33M7QCPAVCNFSM6AAAAACDRZT35KVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTIMBWGY4TIMA>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[alberk8]

Ok, those two has the slave disabled. I am not sure what is the reason for that, You might want to do a custom compile to test. by switching this to ON

[alberk8]

How about try the ESP32_REV3

[bwinklesky]

I need BLE support and would think ESP32_BLE_REV3 is the same as ESP32_REV3, but with BLE enabled.

…

________________________________ From: alberk8 ***@***.***> Sent: Sunday, August 10, 2025 6:44:38 PM To: nanoframework/Home ***@***.***> Cc: Brett Winklesky ***@***.***>; Author ***@***.***> Subject: Re: [nanoframework/Home] Can't use the System.Device.I2c.Slave library for ESP32 device (Discussion #1664) How about try the ESP32_REV3 — Reply to this email directly, view it on GitHub<#1664 (reply in thread)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ALE7XFVHSZCRXUJD3NROAND3M7RPNAVCNFSM6AAAAACDRZT35KVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTIMBWGY4TSMI>. You are receiving this because you authored the thread.Message ID: ***@***.***>

[bwinklesky]

I can run the cmake build, but getting the error. unknown target "ESP32_BLE_REV3". Any thoughts on that?

[bwinklesky]

I used the nanoFramework-All container and was able to build the esp32 image. So, there has to be something misconfigured in the nanoFramework-ESP32 container.

[Ellerbach]

I used the nanoFramework-All container and was able to build the esp32 image. So, there has to be something misconfigured in the nanoFramework-ESP32 container.

If you select now the other dev container, will that work?

[bwinklesky]

I used the nanoFramework-All container and was able to build the esp32 image. So, there has to be something misconfigured in the nanoFramework-ESP32 container.

If you select now the other dev container, will that work?

I still get the ninja error with the ESP32 container. I assume you were asking me to try it again?

[networkfusion]

Just used a devcontainer, using a fresh ESP32 container for the M5Core2, noting that I used docker, rather than podman.

And noting that I had to "clean" (i.e. delete) the "build" directory. And since the CI also uses this dev container, can only assume our user guide needs a bit more TLC.

[bwinklesky]

Hello again! After all the work getting this setup, I tried sending a command to my pH circuit stamp from Atlas Scientific using I2C and it doesn't seem to be working.

My breadboard has pullup resistors on the SDA/SCL lines and tried the same configuration/pin mapping using C++ and it works okay. Is there something else I need to do that might not be documented?

Write command doesn't fail, but when reading it gets hung up.

[bwinklesky]

Looks like the issue is the Bus speed and the I2cSlaveDevice doesn't appear to have a way to set the bus speed. It works using the I2cDevice.Create(settings) where the settings bus speed is FastMode.

What is the use case for the Slave library? I have always thought of the I2C as a master/slave, where any device connected to the SDA/SCL lines is a slave.

[josesimoes]

From your description I'm not sure you're using the correct library... is your ESP32 reading from an I2C device or is the ESP32 being an I2C device that is accessed from an external I2C master?

[bwinklesky]

ESP32 is reading the I2C device. I have a Conductivity and pH sensor that is using I2C. I don't need the Slave library and have removed it from the project.

I didn't think about the ESP32 acting as a slave device and it would make sense if that's the purpose of the Slave library. I've been porting software that was written on Windows IoT about 10 years ago and trying to reuse as much as possible. That wasn't a concept to consider back then.

[josesimoes]

That's seem to be the case. In the end, you don't need the Slave library for anything...