Recent posts

#1

A64 / Re: TWI2 (i2c-2) external pull...

Last post by LubOlimex - Today at 09:17:48 AM

Hello mauricio,

Please be more specific. What interface do you want to use exactly (e.g. SPI, TWI/I2C, UART, just GPIO, etc)? Where are you planning to connect your peripheral at the board exactly (e.g. GPIO header, UEXT, etc)?

Not all interfaces require adding anything. For example, if you use TWI1 at UEXT1 header there are already 2.2k pull up resistors placed.

Usually it is best idea first to check the schematic of your exact board revision here:

https://github.com/OLIMEX/OLINUXINO/tree/master/HARDWARE/A64-OLinuXino/2.%20Older%20hardware%20revisions

#2

UEXT / Re: ESP32-PoE-ISO-16MB --> MOD...

Last post by swaff - November 04, 2025, 08:17:45 PM

This is the Olimex MOD-BME280. It is connected directly to the MOD-IO via UEXT (no cable). The MOD-IO is connected via an included cable to the Olimex ESP32-PoE-ISO-16MB UEXT port.

The MOD-IO is powered via the jack. I've tried both USB and PoE power to power the ESP32 with no change.

The MOD-BME280 is powered via the UEXT connector as I thought that's how it was supposed to work. And most of the time it does work, but sometimes the humdity reading disappears, and even more rarely I've seen temperature and pressure stop working.

#3

A64 / Re: TWI2 (i2c-2) external pull...

Last post by mauricio - November 04, 2025, 06:26:48 PM

Hello. I have an Olinuxino A64, rev. G.

Where in the pcb the resistors should be ?, or the pads ?.

I've looking for them for some time now, cant find.

Thanks

#4

UEXT / Re: ESP32-PoE-ISO-16MB --> MOD...

Last post by LubOlimex - November 04, 2025, 08:28:30 AM

1. How do you power the BME280? If you want to power it from the MOD-IO, it will not work since the 3.3V powering is disabled by default (to avoid accidental short-circuit). Refer to the schematic. You either have to close the pads left for the resistor (or place 0R resistor size 0603) or connect both MOD-IO and BME280 in parallel to the ESP32 board.

2. How do you power the MOD-IO? Is it via the power jack?

3. What exactly is the BME280 module and how do you connect it to the UEXT female connector?

#5

ESP32 / Re: ESP32-P4 micropython port

Last post by LubOlimex - November 04, 2025, 08:17:59 AM

Thank you for this, I am sure someone will find it helpful!

#6

A20 / Re: [Source][PoC] U-Boot + Ker...

Last post by son.nguyenhong - November 04, 2025, 05:30:21 AM

Thanks for this. So the NAND works? It is visible and you are capable to store data on it?

NAND work as old day. But i dont recommend running OS on NAND for production task because data safety.

#7

UEXT / Re: ESP32-PoE-ISO-16MB --> MOD...

Last post by swaff - November 04, 2025, 03:05:19 AM

I have tried plugging just the BME280 in and it works fine. As far as I can tell, it seems to be an issue with I2C communication.

#8

ESP32 / ESP32 vs STM32 vs RP2040 vs Ar...

Last post by sdiment - November 03, 2025, 12:50:59 PM

Hi everyone,

I've recently published a detailed comparison article covering four of the most commonly used microcontroller platforms:
Blog link: https://www.bettlink.com/blog/esp32-vs-stm32-vs-rp2040-vs-arduino-guide

I would love to hear feedback from the Olimex community—especially from those with hands-on experience using any of these boards for industrial, educational, or hobby projects.

Some questions for discussion:

• Which platform do you personally prefer, and why?
• Have you tested ESP32 or RP2040 in applications typically done with STM32?
• In long-term stability & industrial reliability, how would you compare them?
• What do you think about Arduino-level abstraction vs. bare-metal control?
  

I welcome any corrections, comparison points, or benchmarks to help improve the guide.

Thanks!

Best regards,

#9

A20 / Re: [Source][PoC] U-Boot + Ker...

Last post by LubOlimex - November 03, 2025, 08:26:56 AM

Thanks for this. So the NAND works? It is visible and you are capable to store data on it?

#10

UEXT / Re: ESP32-PoE-ISO-16MB --> MOD...

Last post by LubOlimex - November 03, 2025, 08:25:33 AM

Try without the MOD-IO and see how it goes. Just connect the BME280 to the UEXT of ESP32-POE-16MB. This will show if the issue is somehow the MOD-IO board. If that is the case consider connecting the BME280 before the MOD-IO, maybe use UEXT splitter like UEXTx5 or make similar:

https://www.olimex.com/Products/Modules/Adapters/UEXTx5/open-source-hardware