ESP32 Forum

hi guys

honest, have thinked
set the Direction BIT of the GPIO
in this example MDIO is in and output
https://esp32.com/viewtopic.php?f=12&p=6422#p6401


? we need to set the BIT again for input with
https://esp32.com/viewtopic.php?f=12&p=6422#p6418

best wishes
rudi

hi guys

sry for the push
but for me this is honest not clear 100 procent

best wishes
rudi

No, gpio_matrix_in doesn't set input enable. It only writes to the GPIO_FUNCx_IN_SEL_CFG_REG register.

ESP_igrr wrote:No, gpio_matrix_in doesn't set input enable. It only writes to the GPIO_FUNCx_IN_SEL_CFG_REG register.

ok,
i must ask again:
here in this example: GPIO18
https://github.com/espressif/esp-idf/bl ... main.c#L42

is used for MDIO
https://github.com/espressif/esp-idf/bl ... ain.c#L138

why we need not use that the pin is input mode

if we use example gpio32 or 33

we need explizite to use that the gpio32 or gpio33 is in INPUT mode too.

https://esp32.com/viewtopic.php?f=12&t= ... 6508#p6458

is mean GPIO_FUNCx_IN_SEL_CFG_REG is not valid for "GPIO MODE" that then is used for FUNC set pin?
other words:

if we use other function of GPIO as there is named as "FUNC" PIN "NAME"
( use function1 gpio )
then we need to use the GPIO API for set it as INPUT pin by using gpio_set_direction too?

best wishes
rudi

I think the difference you see between GPIO18 and GPIO32 is that GPIO18 has "input enable" bit set by default, while GPIO32 has this bit cleared when it gets configured as an XTAL input pin during startup. This is why you need to set "input enable" for GPIO32 explicitly.

now is clear.
thank you.

best wishes
rudi