ESP32 Forum

Hi,

GPIO15 - is there something special with that one that would prevent it from being pulled low? I can't see anything in the datasheet about it? I'm not using the pin for something else than as an output, configured using GPIO_MODE_OUTPUT and it is only my scope connected to it. I'm using a Sparkfun ESP32 Thing

I'm alternating toggling eight outputs (GPIO_NUM_2, GPIO_NUM_15, GPIO_NUM_5, GPIO_NUM_18, GPIO_NUM_23, GPIO_NUM_19, GPIO_NUM_22, GPIO_NUM_21) and they are all configured equally and they all show the expected LOW-state over 100ms, except GPIO_NUM_15 which only drops 0.3V over ~5ms.

Thanks,

Edit: I just noticed that U0RTS uses GPIO_NUM_15, but disabling the console output doesn't help.

GPIO15 is mapped to MTDO on bootup. How do you initialize this pin in software?

gpio_set_direction, with gpio_mode_output. Is there somerjing else that I need todo to unmap the JTAG interface?

Yes, these calls don't affect the GPIO matrix or IO_MUX so your signal will still be muxed to the JTAG peripheral. Easiest way to fix this is to use gpio_pad_select_gpio to route the pad to GPIO control, or use gpio_config to set up the entire pad at once.

Oh, misunderstanding on my part then. Thanks!