ESP8266 Community Forum

- Sun Aug 30, 2020 11:20 am #88571 Yes. It is interesting the original official schematic doesn't show a capacitor, nor does it show a pull up resistor, although subsequent reverse engineered schematics do.

However, it has been noted before that the original one does not match reality, at least in most cases.

viewtopic.php?p=76989#p77279

has the lid off on a ESP-12E and shows quite a lot of small passives around that area and as the thread notes it does seem to have both pull up and capacitor.

This does accord with my experience of batches of ESP-12Fs from about 10 different vendors, mainly labeled as AI-Thinker modules where so far they have all included these components.

- Sun Aug 30, 2020 6:56 pm #88579 That's really interesting - now you've got me on the hunt for alternative schematics!!! But I bet they're not out there

I've moved to the official Espressif modules, mainly because of the certifications they have, but the ESP-12 series exposes more pins that I need.

I'm currently integrating an SD card reader on the multiplexed SPI pins - I use the others for I2S so my job's harder

- Mon Aug 31, 2020 5:27 am #88586 Yes. I have yet to find a definitive schematic. The manufacturers don't seem to be good at maintaining / updating their documentation.

The reverse engineered ESP-12E one in the esp8266 wiki seems pretty good except that as noted there are a couple of errors on the chip to flash connections.

Edit: Haven't looked more closely at the flash connections I think the schematic may be correct and the wiki misleading.

- Mon Aug 31, 2020 11:06 am #88598

I've moved to the official Espressif modules, mainly because of the certifications they have, but the ESP-12 series exposes more pins that I need.

I'm currently integrating an SD card reader on the multiplexed SPI pins - I use the others for I2S so my job's harder

That is, depending on the submodel. The ESP-12S does not expose the SPI pins. I can't disagree, I never got anything working on it, so I am surprised you did. Or does your SD card reader replace the flash completely?

As soon as I connect something to it, it all stops to boot. Even though the chip select of the connected device (an LCD display) is never activated, so all pins should be HiZ (should be.... probably not, cheap implementation, that would explain a lot). But for the foreseen future the HSPI pins will be sufficient for me, btw.