New ESP32 Board Bootloader

ESP_Sprite
Posts: 8926
Joined: Thu Nov 26, 2015 4:08 am

Re: New ESP32 Board Bootloader

Postby ESP_Sprite » Thu Feb 18, 2021 1:50 am

No. Even if you could make it work software-wise, you would not be able to boot from PSRAM. To be honest, I seriously doubt your designers intellectual capabilities if he seriously believes RAM is a replacement for flash.

lannocm
Posts: 28
Joined: Fri Feb 05, 2021 5:43 pm

Re: New ESP32 Board Bootloader

Postby lannocm » Thu Feb 18, 2021 3:28 pm

OK

Many thanks for your help.

lannocm
Posts: 28
Joined: Fri Feb 05, 2021 5:43 pm

Re: New ESP32 Board Bootloader

Postby lannocm » Fri Feb 19, 2021 7:23 pm

Another thought...

Is it possible to 'piggyback ' flash memory as a separate chip?

Thanks

WiFive
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Joined: Tue Dec 01, 2015 7:35 am

Re: New ESP32 Board Bootloader

Postby WiFive » Fri Feb 19, 2021 7:50 pm

If you want to mount a flash chip on top of the psram chip and do some micro soldering it might work.

lannocm
Posts: 28
Joined: Fri Feb 05, 2021 5:43 pm

Re: New ESP32 Board Bootloader

Postby lannocm » Sat Feb 20, 2021 11:31 am

It doesn't sound like I have anything to lose! Would you be able to help me with what to do?

Thanks

WiFive
Posts: 3529
Joined: Tue Dec 01, 2015 7:35 am

Re: New ESP32 Board Bootloader

Postby WiFive » Sat Feb 20, 2021 4:11 pm

Really your designer should fix the design and pay for new boards. It's going to be very difficult to solder wires directly to the pins on the esp32 chip and you're going to end up with something messy and fragile. If you don't have an idea of what to do it's probably not worth trying.

lannocm
Posts: 28
Joined: Fri Feb 05, 2021 5:43 pm

Re: New ESP32 Board Bootloader

Postby lannocm » Mon Mar 08, 2021 12:20 pm

Hi,

I'm waiting for a new design from the designer, who has admitted that he missed the flash chip of the first design. I'm still keen to have a go at fixing the original board and I have more information now about the flash chip to use. I've also done a bit of research and I believe that I now know how to solder in the flash chip but I would like to run it past you guys for verification.

The flash chip is W25Q128JVSIM TR and has the following pin config:
flash chip pin config.png
flash chip pin config.png (84.93 KiB) Viewed 4807 times
It shares a lot of the pins with the PSRAM and, according to the ESP32 hardware design, can be multiplexed with all of the pins, with the exception of the CS pin.
PSRAM chip pin config.png
PSRAM chip pin config.png (47.21 KiB) Viewed 4807 times

Below is the ESP32 DOWDQ6 pin config. If understand the documentation correctly, pin 30, labelled SD_CMD is what is used to connect to the CS pin on the flash.
ESP32-DOWDQ6 chip pin config.png
ESP32-DOWDQ6 chip pin config.png (51.35 KiB) Viewed 4807 times
So, I have consolidated the information in to a table, which I will put in the next post.

lannocm
Posts: 28
Joined: Fri Feb 05, 2021 5:43 pm

Re: New ESP32 Board Bootloader

Postby lannocm » Mon Mar 08, 2021 12:25 pm

Here is the table:

I have marked, in red circles, where I think the soldering should be done but I'd be grateful for any thoughts anyone has on what I have said and shown.

Thanks.

Soldering points - part 1.png
Soldering points - part 1.png (369.55 KiB) Viewed 4806 times
Soldering points - part 2.png
Soldering points - part 2.png (167.4 KiB) Viewed 4806 times

WiFive
Posts: 3529
Joined: Tue Dec 01, 2015 7:35 am

Re: New ESP32 Board Bootloader

Postby WiFive » Mon Mar 08, 2021 4:49 pm

You are on the right track, unfortunately SD# does not map directly to IO#, you should use the SPI labels. Check the esp32-wrover schematic in the datasheet. I don't know if sharing a clk pin is officially supported.

lannocm
Posts: 28
Joined: Fri Feb 05, 2021 5:43 pm

Re: New ESP32 Board Bootloader

Postby lannocm » Mon Mar 08, 2021 7:55 pm

Ah!

So, I think I have the pins correct but the wrong labels on them. I'll double check that shortly.

As for the clk pin, according to the hardware guidelines, psram and flash can share the same clock, though there is a separate clock on the esp32. At least, that's my understanding.

Also, can you tell me what the difference is between /CS and CS#, please? I get that CS# is inverted but not what /CS is.

Thanks
Screenshot_20210308-194718_Acrobat for Samsung.jpg
Screenshot_20210308-194718_Acrobat for Samsung.jpg (435.32 KiB) Viewed 4770 times

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