Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)
User avatar
By Markus Gritsch
#9634 Hi,

I tried getting PULLDOWN in the Lua firmware working (viewtopic.php?f=24&t=1600), but up to now to no avail. When calling
PIN_PULLUP_DIS and PIN_PULLDWN_EN for the respective pin, the behaviour seems to be like pull-up is active.

Has anyone tried this and can confirm, that pulldown is working?

Thanks,
Markus
User avatar
By Markus Gritsch
#9670 BTW, my intention of using pull-down is to be able to connect a switch to GPIO0 or GPIO2 of an ESP-01 board. Because normal operation of the module only happens when neither of the pins during boot is connected to GND, the only working configuration IMO is to have the switch connect one of the GPIO pins to VCC when closed and have the GPIO pin floating when the switch is open. Pull-down would yield to a 0 in the open state.
User avatar
By lethe
#9681
Markus Gritsch wrote:BTW, my intention of using pull-down is to be able to connect a switch to GPIO0 or GPIO2 of an ESP-01 board.

I don't get your need for a pulldown here. Just connect a resistor from VCC to the GPIO and a button from the GPIO to GND.

Pull-down would yield to a 0 in the open state.

What's the issue with having it read 1 in open state? You can always invert it in software.