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ATtiny817 seesaw as an I2C to UART bridge?

Posted: Wed Jan 31, 2024 12:03 am
by steveputz
Am I correct that the UART module is not configured in the pre-burned seesaw firmware?

Specifically the ATtiny817 seesaw version breakout? https://www.adafruit.com/product/5233

I would like to add an additional hardware UART to an ESP32 project where I'm also short on GPIO/ADC pins, so using a seesaw with pre-burned firmware to get these via I2C would be convenient.

If I have to write and load custom firmware into the ATtiny to create an I2C to UART bridge, it's not as convenient.

Re: ATtiny817 seesaw as an I2C to UART bridge?

Posted: Wed Jan 31, 2024 2:37 pm
by mikeysklar
Looking at the SeeSAW commits I see UART functionality is present. Still without examples plus enabling and compiling it could be a big detour.

Which ESP32 are you using? The Feather V2 (Pico based) has three UARTs.

Re: ATtiny817 seesaw as an I2C to UART bridge?

Posted: Fri Feb 09, 2024 10:03 pm
by steveputz
I'm very familiar with the Feather V2.
For this project I'm using a non-Adafruit ESP32 board (with a SIM7000 cellular modem on the same board).
It is an ESP32-wrover with 3 UARTs, but I need a total of 4 serial connections for my application (including the USB debug serial, which I'm reluctant to give up). I'm currently filling the gap with software serial (which I don't entirely trust).

When you write "enabling and compiling it could be a big detour", do you mean the UART seesaw code is in github, but not included in the pre-programmed multifunction seesaw units shipped from Adafruit?

I was hoping not to have to reprogram the ATtiny, and also hoping to have example code.

I will likely incorporate a pre-programmed ATtiny seesaw in my project to get more GPIO and ADC, but also getting hardware UART via I2C would be a bonus. I cannot tell from the seesaw sources on github whether enabling UART will still allow GPIO And ADC via seesaw as well.

Re: ATtiny817 seesaw as an I2C to UART bridge?

Posted: Sat Feb 10, 2024 6:11 pm
by mikeysklar
This SeeSaw UART will not be convenient. It will require recompiling, programming and there are no examples I can find to use it.

If you need a lot of UARTs does it make sense and bring in another controller? You are familiar with the Feather V2 which would buy you more UARTs.

In some cases giving up a single UART is not so bad if you have a debug port and a J-Link. The Metro ESP32-S3 includes a 2x5 SWD connector. There are other variations on specific ESP32 modules.