my breakout board for the esp8266 - Page 1
Forum section: electronics / general

author: linux-works
author_rank: Super Contributor
timestamp: May 18, 2015, 12:01:37 am
content: needed one to flash firmware to these modules, so threw this together:set green jumper for 3.3v regulator (onboard to220) or to use ftdi dongle's 3.3v. set yellow jumper for program mode vs run mode. white button is for reset.level matching is via 1k series R from tx source into a 3v zener, to clip at 3v. seems to work ok. no level matching on other direction since none is needed.just a few hours work for a weekend (mostly planning where things would go; the build was much faster once I decided where all the parts would best be placed).

author: JoeO
author_rank: Frequent Contributor
timestamp: May 18, 2015, 02:38:31 am
content: Nice - Do you have a schematic or do you have a link to it?

author: zapta
author_rank: Super Contributor
timestamp: May 18, 2015, 03:06:08 am
content: Very nice!How about having two buttons, one for Run mode and one for Programming mode? I did something similar with an ARM processor using a capacitor that keeps the ISP pin down after the main reset is released.https://github.com/zapta/arm/blob/master/pro-mini/board/arm-pro-mini-schematic.pdfBTW, the stock flash on those ESP8266 have low endurance in general, so expect the module to fail if you do extensive development. I ordered compatible Flash chips that hopefully (but I don't know for sure) have high endurance.

author: linux-works
author_rank: Super Contributor
timestamp: May 18, 2015, 06:10:17 am
content: Quote from: JoeO on May 18, 2015, 02:38:31 amnot schematic or link; I just had a pinout of the ESP module and an idea of what had to be connected where.here's one that is a good starting point:http://www.martyncurrey.com/arduino-to-esp8266-serial-commincation/I'm not using a 1k/2k divider. I'm using a zener that is around 3v and a 1k series resistor (R goes from the arduino or the ftdi; the thing that talks TO the esp module and is at 5v. we 'clip' that 5v at 3v with the zener, so the zener goes across the rx input of the esp and gnd, and the 1k goes from the source tx to the zener. simple stuff. the other direction has no level conversion or clipping; its at 3v and the arduino can see 3v as a 1 just fine.I'll post a photo of the bottom of the board and a flat photo of the top of the board and you'll see how silly-simple the hookup is. most connections are short and direct, which was the plan all along.the 3 pin header for power select lets you pick the voltage going into the 3.3v reg (which is coming from the ftdi 3v/5v out) and the header lets you pick the voltage coming out of the 3.3v reg; so its a 'pre and post' kind of jumper. the ftdi I have in the photo is 3.3v based and so I put the jumper 'near' the ftdi to select its 3.3v Vcc out and bypass the onboard to220. if I'm coming from a 5v ftdi dongle, then I'll use the local to220 reg chip and move the jumper 'up' toward that reg chip, to select it. remove the jumper for a short bit and you remove power to the esp (to reboot it).the other jumper is the run/program jumper and I would use a switch for that. didn't have a nice pcb mount switch handy but it would be better than a raw jumper.as for the flash wearing out, is that during regular use or just reprogramming? I would think you'd have hundreds or more cycles of erase/write, no?

author: linux-works
author_rank: Super Contributor
timestamp: May 18, 2015, 07:27:42 am
content: well, its better than nothingthat does at least locate the parts and what connects to what. thank god for multi color kynar, loledit: already noticed a typo. the bottom '5v' in white should be 3.3v! the esp module has to have 3.3v of course. I was just not thinking when I entered that into photoshop. photo is already posted, so its too late to undo (easily). oh well. its just the annotation that's wrong. the wiring is all correct.

author: baoshi
author_rank: Regular Contributor
timestamp: May 18, 2015, 09:57:07 am
content: I designed a circuit that uses one button short press reset, long press enter program mode.https://www.tindie.com/products/Ba0sh1/esp8266-esp-0712-full-io-breadboard-adapter/The schematic is open. Just click the documentation on the link above.

author: TJ232
author_rank: Frequent Contributor
timestamp: May 18, 2015, 11:12:08 am
content: Quote from: linux-works on May 18, 2015, 07:27:42 amNice work:)Can be proudly posted on CBDB thread :https://www.eevblog.com/forum/microcontrollers/esp8266-breadboard-time-cheap-and-dirty-basic-development-board-%28cbdb%29-!!/

author: JoeO
author_rank: Frequent Contributor
timestamp: May 18, 2015, 02:21:17 pm
content: Thanks - I can use your pictures to duplicate the board.

author: linux-works
author_rank: Super Contributor
timestamp: May 18, 2015, 03:16:17 pm
content: Quote from: JoeO on May 18, 2015, 02:21:17 pmyes, please do. have fun!