ESP32 Forum

Hello,
it is needed to start the program immediately after power-on (over 3V3-pin) W H I T O U T pressing RST.
But it doesn't, I have to press RST.
I red, it should for a immediately start connected be GPIO-0 andGPIO-2 together over 10k to 3V3 and GPIO-15 over 10k to GND.
And there is the problem:
I use a TTGO T-Call V1.4 ESP32 Wireless Modul SIM Antenne SIM Karte SIM800L Modul, marked as LILYGO.
On the board is a ESP32-WROVER-B.
Searching the GPIO 0, 2, 15 pins do I find in the ESP32-WROVER-B data sheet some numbers (25, 24, 23).
But the ESP32-WROVER-B has only 38 pins, my LILYGO TTGO..... has 42 pins. Where are on my board that GPIO's?

Alternatively:
if the connection GPOI 0 and 2 to 3V3 and GPIO 15 to GND not solving my problem, what else can I do for an start immediately after power-on? In the manuals is that case not described

Regards
aabbcc

Your power rails may be rising too slowly. Try adding e.g an 10uF capacitor between EN and GND.

Hello,
thank you for your fast answer!
The source of power is very potent (2 x 1000mikroF) and it is able to start the board after pressing RST.
At the start of the program isn't needed to much power, because the SIM800L is during start phase out of order. It comes later.
I should know, where the GPIO's are on my board with 42 pins instaed of 38 pins.
I didn't find any datasheet!
regards
aabbcc

Nevertheless, I will check with the recommanded capacitor!
regards
aabbcc

Note I'm not saying it isn't very powerful, I'm just saying it may be slow to get from power-off to full voltage. The 2x1000uF may be to blame there; the power rails will get from 0V to whatever they should be pretty slowly as they must fill those capacitors first.