ESP8266 Community Forum

- Fri Jan 29, 2021 4:17 pm #90365 I'm quite confused on ESP pin connections for programming or normal run mode, though this question is widely asked on the internet but wanted to be sure.

I'm designing a PCB where I want ESP run in normal mode, but I can connect through header to program ESP please refer to images.

Please look at my schematic U10 is programming header, I will connect it to ESP-01 header (please refer to image)

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- Mon Feb 01, 2021 1:17 am #90379 to enter bootloader mode io 0 must be LOW at reset. that is all.

io 0, 2 and 15 are boot configuration pins. the modes configured by 2 and 15 are used with uncommon configurations. for esp8266 with application in external flash io 2 must be HIGH at boor and io 15 must be LOW at boot. the pull down resistor on io 15 is missing in your schematics

- Mon Feb 01, 2021 10:35 am #90386 I'm using ESP12E and i believe i have to pull up GPIO 2 and pull down GPIO 15, is that right?

if you pull down GPIO15 with 10k resistor for boot, then in the program (after boot) can i send signal with state HIGH

- Tue Feb 02, 2021 1:44 am #90388

I'm using ESP12E and i believe i have to pull up GPIO 2 and pull down GPIO 15, is that right?

if you pull down GPIO15 with 10k resistor for boot, then in the program (after boot) can i send signal with state HIGH

yes and yes.

don't use io 15 as CS for SPI slave if you connect one