ESP8266 Community Forum

- Fri Sep 29, 2017 3:38 am #70440 Hi,
I'm designing a board with a reset button and I'm wondering, if I should just tie RESET and CH_PD/EN together (saves one resistor in the design). I've read that you can/should use CH_PD/EN for reset.

What is the difference? I already found out that with EN HIGH and RESET LOW, GPIO 16 is HIGH and all IOs except 4 and 5 are pulled HIGH, whereas with RESET HIGH and EN LOW, all IOs are floating.
But are there any other differences?

Will connecting both cause any issues? I cannot think of any... I guess even connecting IO16 to RESET and EN for deep sleep wake-up will still work.

Thx

- Fri Sep 29, 2017 5:33 am #70442 Definitely separate them! They have different boot reason codes and can be used very well for branching at start.

- Fri Sep 29, 2017 6:28 am #70443 Okay, I get that. If I tie RST and EN together, I won't be able to distinguish between boot caused by RST or EN / Power loss. (I guess toggling EN is almost the same as removing VCC)
That really is a minor issue... Any other issues?

Btw. where should I connect the RESET switch to, if I seperate RESET and EN? Some do suggest EN. See also here: http://hallard.me/esp8266-autoreset/
On the WeMos D1 Mini board, the reset switch is connected to RESET.

At least for my application it is not important how the reset was caused...

- Fri Sep 29, 2017 8:04 am #70448 CH_EN puts the module in the lowest powered state. RTC memory is not powered. I have been using CH_EN as a reset in my latest project. viewtopic.php?f=11&t=15929

I have RST connected to GPIO16 in case I want to use it for sleep/wake operation. I have some circuitry connected to the three button switches that will provide a high on CH_EN to power up the device. I use a GPIO pin to hold CH_EN high. After a timeout with no activity the GPIO pin goes low and turns the ESP off.

I like the option of using CH_EN as a reset for the ESP8266.