ESP8266 Community Forum

- Mon Apr 18, 2016 8:23 am #45701 Hi and thank you very much for your answer!

If you ever want to use deep sleep you will need a 1k between CH_PD & GPIO 16

Just one between or do i need a jumper? What is the reason behind the resistor?

Try and get a good sized pad on the tab of the AS1117

I don't use an AS1117 anymore because i read this thread: viewtopic.php?f=13&t=9534 and i think a HT7333 would be a better idea if i want to use the ESP8266 with batteries (for low power).

This is my board layout currently. Are the pads big enough? I don't know anything about the heat dissipation of the HT7333 because there is no information about it in the datasheet.

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- Mon Apr 18, 2016 8:44 am #45708

Just one between or do i need a jumper? What is the reason behind the resistor?

Several weeks ago, people were complaining that they were unable to upload new sketches to flash while it was in deepSleep(). I've then investigated and found that GPIO16 wasn't driving its output to the RES pin in OpenDrain mode (meaning stay floating until bringing a LOW for WakeUp) but instead was driving its output with a strong HIGH, preventing any external reset, such the one coming fro USB-TTL or any other circuit, to send a LOW from external source, collision between both HIGH and LOW signal, the strongest HIGH was winning.

By adding a series resistor between GPIO16 and RES (value can be 220R, but 1K works well too), it allows the LOW signal on RES pin to become the winnner...

- Mon Apr 18, 2016 9:30 am #45717 Okay, thanks for the detailed explanation

Should the resistor be between CHPD and GP16 or between RESET and GP16?

- Mon Apr 18, 2016 9:51 am #45719 GPIO16 and RES !
(CH_PD is only used for external PowerDown, unrelated with deepSleep() ...)