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#21

ST / Re: BB-STM32WL and Platformio/...

Last post by winfried - February 26, 2026, 04:42:05 PM

Workin manual: the sequence is with buttons to GND:

BOOT0 -> low  (button closed)
RESET -> low  (button closed)
RESET -> high (button released)
BOOT0 -> high (button released)

--
To understand the Transistor Logic in ESP-PROG it did, thanks to KiCAD, a fast simulation on /RTS and /DTR to DCOM and EN see picture below:


It seems, there is no combination of both signals being low at the same time, so it does not work, or am I wrong ?

#22

ESP32 / Re: What board should I use?

Last post by fredy - February 26, 2026, 02:58:02 PM

Hi!!

Thanks for response and your advise!

Last question: could I use POE boards without use the power of POE and use the ethernet to send data?

Thanks in advance!

#23

ST / Re: BB-STM32WL and Platformio/...

Last post by LubOlimex - February 26, 2026, 08:31:29 AM

Hmmm, you might need oscilloscope for this one. I think the problem comes from ESP-PROG logic that is made for ESP auto-boot and STM32 boot logic is possibly different. Maybe try with

Code Select Expand

-i '-rts,,-dtr,100,dtr:,-rts'

Code Select Expand

upload_flags = -R -i '-rts,,-dtr,100,dtr:,-rts'
I think to enter STM32 system bootloader:

BOOT0 = HIGH
RESET = LOW
wait ~100 ms
RESET = HIGH
BOOT0 can stay HIGH (or go LOW after reset)

To exit bootloader:

BOOT0 = LOW
RESET pulse again

If it does not work, the signals may be inverted on your ESP-PROG. In that case, swap rts with -rts and dtr with -dtr. If possible, verify with a multimeter or oscilloscope that:

EN actually goes LOW during reset and BOOT0 actually goes HIGH during boot. That will show whether inversion is the issue.

#24

ST / Re: BB-STM32WL and Platformio/...

Last post by winfried - February 25, 2026, 09:24:01 PM

Trying to use the DCM and EN outputs from ESP-PROG for RESET and BOOT0 on BB-STM32WL board.

Also for "STM32flash" there are options to handle boot and reset, with "dtr" and "rts" pins with your ESP-PROG, (so I can make a dev connector on my board):

Code Select Expand

Code Select Expand

  ...
 -i GPIO_string  GPIO sequence to enter/exit bootloader mode
            GPIO_string=[entry_seq][:[exit_seq]]
            sequence=[-]n[,sequence]
 -R      Reset device at exit.
 ...

Code Select Expand

upload_flags = -R -i '-rts,,-dtr,,,dtr&rts:,-dtr,,,dtr'
        ; GPIO sequence adding delay after port opening:
        ; - entry sequence: rts=low,200ms,dtr=low, 300ms delay, dtr&rts=high
        ; - exit sequence:dtr=low, 300ms delay, dtr=high

Following questions:

Assume connect EN to RESET and DCM to BOOT0 I cannot find a working sequence.
Do not understand what is the logic of DTR with RTS  to EN and DCOM signals on ESP-PROG.

What could be a sequence of DTR and RTS to: "DCM low" and "EN low, 100ms, high" for reset and make DCM high again ?

#25

New Product Ideas / Re: Which board might fit for ...

Last post by LubOlimex - February 25, 2026, 08:20:57 AM

I think the only board that fits the open-hardware criteria, 2GB of RAM and being slim is iMX8MP-SOM-4GB-IND. The rest of the SOM designs we have are not open-source hardware The idea of the SOM is to design own bottom board that exposes only the interfaces you need, while the EVB board features most of the peripherals to serve as evaluation basis for the chip, the peripherals and the Linux.

The web-page is here:

https://www.olimex.com/Products/SOM/NXP-iMX8/iMX8MP-SOM-4GB-IND/open-source-hardware

#26

New Product Ideas / Which board might fit for my p...

Last post by ted - February 25, 2026, 12:03:18 AM

Hi there,

this seem to be the only topic where my question might fit - so here we go:

i am currently tinkering on a diy-eink-tablet - so basically like a "normal" tablet - but instead of a lcd it will have an eink display. There are commercial available ones (remarkable, supernote, viwood, boox etc.) - but none of them is open (theres pinenote - but thats not really usable) and most use android.
I first landed on all the pi-named stuff - and ended up having the "zero-format" - like radxa-zero3w as reference - as it has no bulky connectors like ethernet - which a tablet does not need. Also i had a look at som's - as i had the idea to use a carrier board with a "upgradable" module on top. Then again there does not seem to be a standard connector to the carriers and most carriers also are "fat" with ethernet and USB sideways.

I already have open hardware controllers for display and touchscreen i want to use, same goes for a DC/DC converter.

So long story short - i am looking for a sbc or som that is
- preferably open hardware
- small
- capable to run linux (plan is to run something armbian or alpine/postmarketos with lomiri and software like xjournal+ for handwriting). So it should be possible to have 2GB RAM or more, maybe emmc, maybe possibility to add a SD-Card.

So looking at your boards i am not sure which one might fit. I found some who just used a raspbery and cut of or desoldered "fat" connectors like ethernet - but i'd prefer this as a last resort.

Which of your boards would you recommend for such a case?

#27

ESP32 / Re: determine available (unuse...

Last post by LubOlimex - February 24, 2026, 09:36:09 AM

Make sure the PSRAM is enabled and set to OPI (if it is set to QSPI it will not be read).

I also made this Arduino demo that shows the chip info (revision, SPI size, RAM size) for the chip, make sure Arduino IDE settings are the same:

https://github.com/OLIMEX/ESP32-S3-DevKit-LiPo/tree/main/SOFTWARE/Arduino/ESP32-S3-chip-info-demo

#28

ESP32 / Re: determine available (unuse...

Last post by LubOlimex - February 23, 2026, 08:24:09 AM

Something wrong with the software setup and installation. Better search for similar problem in ESP-IDF or VScode forums.

Maybe try Arduino IDE with these settings: https://github.com/OLIMEX/ESP32-S3-DevKit-LiPo/blob/main/SOFTWARE/Arduino/ESP32-S3-DevKit-Lipo-bat-sense/Arduino-Settings.jpg

#29

ESP32 / determine available (unused) f...

Last post by Timbopoise - February 21, 2026, 12:32:12 AM

I've searched for an answer and reviewed espressif's documentation but no clear answer.  I'm sure I missed something.

when I run idf.py size I get an interesting table of information but the Flash usage is blank.

I'm on Ubuntu 24.04, VScode, ESP32-S3 8R8

Thanks

#30

ST / Re: BB-STM32WL and Platformio/...

Last post by winfried - February 20, 2026, 01:02:06 PM

ok, I overlooked it, anyway thanks for the schematics.

BTW fyi:
I found you are using XTAL so, in radiolib we need to set TCXO_VOLTAGE to 0V, so it runs.