ESP8266 Community Forum

- Sat Jan 09, 2016 12:49 am #38275 I found it really difficult to figure out proper documentation and pin connection for ESP12E module. The internet is full of examples done with ESP01. Could someone please post circuit diagrams for following 3 scenarios:
1. ESP12E in Flash Mode to load NodeMCU (with FTDI Converter and external power supply).
2. ESP12E in program mode (to be programmed with ESPlorer IDE along with FTDI Converter and power supply)
3. ESP12E in run mode (with an external power supply only and 2-3 GPIO pins used)

I was also looking for a suitable power supply circuit for ESP12E. I know the power requirement, 3.3v and max 250mA current. But, I hardly managed to find a AC to AC stepdown transformer which outputs 250 mA current. Could a 500mA output transformer be used to operate a LM317 voltage regulator circuit to supply power to ESP12E? I mean, I don't have the concept if a ESP12E would draw only 250mA current from the circuit or will I make the mistake of exposing it to 500mA current when attached to such a power supply circuit.

Thanks and regards,
Prithwiraj Bose

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LM317 Based High Current Power Supply Circuit | Buy IoT Modules in India

- Sat Jan 09, 2016 10:24 am #38302 For the Power Supply, Yes, it requires to be able at least 300mA. Some capacitors need to be added to filter noise but also to provide power reserve in case of surge/spike in current consumption, so 0.1uF for filter along with 100uF for reserve.
To choice the power supply, you need it to be able to provide this 300mA, this means its rating should be higher, so you can use 500mA, or even 1A or 2A.

For the voltage regulator, LM317 is NOT a LDO (low drop out), it has an "headroom dropout" of about 3V, so, if you use a 5V PSU, it won't work because 5V-3V=2V. So, either you change the PSU to a 6V or more, or you choose a LDO regulator such as AMS1117, which has a dropout of 1V.

For wiring, CH_PD/RES/GPIO2/GPIO0 need to have pullup resistors to VCC around 4K7 or 10K while GPIO15 needs to be pulled-down to GND.

- Tue Feb 02, 2016 9:13 am #40264 Connected pins with 1k resistor and 10uF capacitor between VCC and GND.

ESP12E just blinks and post garbage to serial monitor.

- Wed May 31, 2017 5:38 pm #66589 Hi Prithwiraj Bose,
I have just programmed ESP12E via Arduino IDE successful. Main problem is from power 3.3V. ESP12E needs high current power source -> we must prepare good one.
For more detail steps how to program, please visit this blog:
http://engineer2you.blogspot.com/2017/05/esp12e-arduino-programming.html

I hope it can help you and others.