ESP32 Forum

Hi

We have a small custom board that uses the wroom 32D. We have a few of these that we have been developing the esp32 program on. They are minmal boards and don't have an on board uart. We use an external usb uart instead and that works fine.

Recently got some more modules and decided to get the 8MB version just in case we needed the extra room. Had the modules fitted to a couple of pcbs, but can't get them to program. We purchased the modules from Mouser so a reputable supplier.

It would appear to be a baud rate issue. Pressing enable to reset the module results in some text being output. On the 4MB modules this is readable in the rs232 terminal, but with the 8MB modules it is garbage.


Looking with a scope I can see the same data is output but on the 8MB modules as on the 4MB but it takes just sligtly longer for the same data.

The baud rate is fixed in the upload tools so anyone any idea how I can program / use these modules or what is going on!

Thanks for any help / ideas

Mark

Hi All

I did manage to find a solution

I was using a USB uart with a silabs cp2102 chip on board. This has worked well for months but would not work with the 8MB modules

I changed to a usb uart with the silabs cp2104 and that worked fine

Actual ref on the ic is sil 2104. So I am guessing cp2104.

Looking at the scope grabs there is a small timing difference between the 2 modules as an example an edge at 155us on the 4MB board was at 157us on the 8MB board so just over 1% difference.

Hope this is useful for any body with a similar problem

Mark

That is interesting. Do you mean the tx0 pin? So what were your calculated baud rates based on scope?