ESP8266 Community Forum

- Fri Feb 20, 2015 1:50 pm #10260

MTD0 is jumpered either way on that schematic, Markus. ESP-01 does not have anything on that pin.

And if you look at the table in the top right corner of that schematic, it says MTD0 has to be pulled down to boot from flash (with GPIO0 and 2 pulled up), otherwise it boots from SDIO.

The default solder bridges of the jumpers on the board are
MTD0: 0
GPIO0: 1
GPIO2: 1

- Fri Feb 20, 2015 2:57 pm #10263

The default solder bridges of the jumpers on the board are
MTD0: 0
GPIO0: 1
GPIO2: 1

Ah, thank you, I missed that. Useful information.

I did some checking. On the ESP-01 pin 13 (MTD0) is pulled directly to ground with 0R. Must be a trace under the chip as it is not visible. Is there a schematic for that board anywhere? I don't seem to have one.

On the ESP-12 it is brought out as GPIO15 and needs to be attended to.

Also, I have noted that GPIO0, even with a 10K pullup, outputs a short burst of 26 MHz clock on wakeup from sleep and on power reset. This could be important if the pin is used for I/O.

The Olimex looks like a nice board to work with for development.

ESP8266 for dummies, LuaLoader and project updates: http://benlo.com/esp8266

- Fri Feb 20, 2015 3:35 pm #10264

Also, I have noted that GPIO0, even with a 10K pullup, outputs a short burst of 26 MHz clock on wakeup from sleep and on power reset. This could be important if the pin is used for I/O.

You might want to have a look at the attached spreadsheets to this post: viewtopic.php?p=9775#p9775
'pin_reg.xlsx' contains on the 'Reg' spreadsheet the info "after reset, the default is function5 to export the clock".

The Olimex looks like a nice board to work with for development.

Yes they do everything open source, and their designs are quite solid. They also have this evaluation board (with the board above included) https://www.olimex.com/Products/IoT/ESP ... e-hardware for about 10 Euro.

- Fri Feb 20, 2015 3:43 pm #10265 Thanks Markus.

And €10 will be even cheaper for us after Greece defaults.

ESP8266 for dummies, LuaLoader and project updates: http://benlo.com/esp8266