ESP8266 Plug

[Medo]

ESP8266 Plug is a small USB to serial bridge intended to ease debugging of ESP8266 WiFi serial transceiver. Using your computer’s USB for serial port emulation will definitely make debugging easier than doing first time discovery with microcontroller.

Since usual solution of just abusing FTDI cable cannot really supply this module with enough current once things get going, there is a separate 3.3 V voltage regulator for all the peaks ESP needs.

Additionally there are two special solder bridges on the bottom. One for putting ESP8266 module into bootloader mode so it can be revived in cases of bad firmware updates. Another bridge controls bootloader via DTR signal line - useful for automation.

Whole device is quite small in size and easy to assemble for anyone with SMD soldering skills.

More details at:

• https://www.jmedved.com/esp8266plug/
• https://bitbucket.org/jmedved/esp8266plug/

PS: No, I am not selling them. If you want one, get gerbers from pages, parts from DigiKey, and solder them yourselves.

[Monkeh]

Why the hugely expensive FT232RL?

[Medo]

I was considering using MCP2221. While it is nice (and rather cheap) IC, I found it misbehaves under Windows when you plug/unplug it often. Since this board is intended for debugging where plugging/unplugging is pretty much the only thing you will do, I decided to go with FTDI which works flawlessly regardless of their stupid driver fiasco.

And no, Prolific was never on my mind due to religious reasons.

[Monkeh]

I'm not questioning the use of FTDI!

Why the chip which costs over twice as much as a smaller, newer one?

[Medo]

You need to be a bit more precise then.

I will assume that you are referring to the FT230X. First thing that I hate about that one is need for external caps and resistors. Something that is smaller on paper ends up using same amount of space (and usually more) if you want to keep all your components on a single side. Additionally there is no DTR on its pins. Yes, you can use RTS instead but I cringe at use of a flow control signal for anything else.

I find that FT232R works best for me and $2 difference isn't too steep a price for comfort.

Since PCB layout is publicly available, someone can always swap the chips.

[Monkeh]

FT231..

The caps are not required, just recommended. You'll find them used on all reference FT232RL implementations, too. Probably a good thing to have when stuck on the bottom of an RF board. The resistors can be awkward, though, fair point. I've become too comfy with tiny parts.

[Medo]

I am referring to 47 pF capacitors on D+/D- line. I don't see them on FT232R reference implementation but they are drawn on FT230X.

I must confess I've never tried using FT230X without them. I sort of always assumed they are mandatory.

[Monkeh]

I am referring to 47 pF capacitors on D+/D- line. I don't see them on FT232R reference implementation but they are drawn on FT230X.

I must confess I've never tried using FT230X without them. I sort of always assumed they are mandatory.

I am aware, look at any of FTDIs own products using the FT232R, they're present. They're slew rate limiting caps for RFI.

You could benefit from a few more vias down to ground.

Neat little board, though.