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Author Topic: Rev A vs Rev B  (Read 1178 times)


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Rev A vs Rev B
« on: December 04, 2016, 01:49:25 PM »
Hi, some month ago i order

and i received the rev B model.

it works well and it has a push button to put the device in bootloader mode.

Now i order again but you send to me the rev A model !!!!!!

It has not the push button, so now , how i can put the device in bootloader mode?


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Re: Rev A vs Rev B
« Reply #1 on: December 06, 2016, 04:38:06 PM »
You need to set pin #21 (GPIO0) to GND while you power the board. Alternatively, instead of disconnecting the power supply you can also reset by setting pin #13 (RSTB) to GND. So, the sequence is, set GPIO0 to GND, then plug the power supply or set RSTB to GND for a moment, and then you'll be in bootloader mode. Refer to the schematic for more details on the connection: https://github.com/OLIMEX/ESP8266/blob/master/HARDWARE/MOD-WIFI-ESP8266-DEV/MOD-WIFI-ESP8266-DEV_schematic.pdf MOD-WIFI-ESP8266-DEV

How to set GPIO0 to GND? There are two ways – one of them requires some wires and probably a bread board; the other way requires soldering cutting the SMT jumpers. The first way follows the algorithm described above just connect pin #21 (GPIO0) to pin #2 (GND) before you apply power, and then disconnect the connection between GPIO0 and GND. The other way with changing the position of the SMT jumpers (that control the different boot modes FLASH, UART, SDO) is described in the next document, but this method requires cutting between pads and soldering at least two times: https://www.olimex.com/Products/IoT/MOD-WIFI-ESP8266/resources/MOD-WIFI-ESP8266_jumper_reference.pdf jumper reference

Best regards,
Technical support and documentation manager at Olimex