How does TOUCH_PAD_SELX Map into the GPIO_SEL_X in esp-adf?

[mkseven32]

Hi all
As esp-adf using a new framwork to develop, and Touch Peripheral init is like below :

Code: Select all

    periph_touch_cfg_t touch_cfg = {
        .touch_mask = TOUCH_PAD_SEL4 | TOUCH_PAD_SEL7 | TOUCH_PAD_SEL8 | TOUCH_PAD_SEL9,
        .tap_threshold_percent = 70,
    };
    esp_periph_handle_t touch_periph = periph_touch_init(&touch_cfg);

refer to the esp32_lyrat broad HDK，those touch pad are connect to GPIO33，GPIO32,GPIO13，GPIO27

Why does it mapping like below？
TOUCH_PAD_SEL4 ========>GPIO33 ???????
TOUCH_PAD_SEL7 ========>GPIO32 ???????
TOUCH_PAD_SEL8 ========>GPIO13 ???????
TOUCH_PAD_SEL9 ========>GPIO27 ???????

and this make me confused how does TOUCH_PAD_SELX Map into the GPIO_SEL_X ？
if we using different Hardware design， how to config touch pad about TOUCH_PAD_SELX mapping？

BR！！

[WiFive]

[mkseven32]

thanks ！