Harden Si4684 RSTB config and document power sequencing.

Enable GPIO_PULLDOWN_ENABLE during gpio_config so RSTB cannot glitch high before gpio_set_level(0), and add manual validation notes explaining why the internal pull-down complements the external one. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-07-07 08:34:52 +02:00
parent de0b120551
commit 2e44a166e1
4 changed files with 178 additions and 1 deletions
@@ -96,7 +96,14 @@ public:
    Si4684Driver& operator=(const Si4684Driver&) = delete;

    /**
-     * @brief    boot — cold-start: load patch, image, and configure I/O.
+     * @brief    boot — cold-start: pulse RSTB#, load patch/image, configure I/O.
+     *
+     * @details  Pulses RSTB# (active-low reset): gpio_config enables the ESP32
+     *           internal pull-down while switching GPIO38 to output so the net
+     *           cannot glitch high before gpio_set_level(0). That guards the
+     *           Si4684 datasheet rule that RSTB must stay low until supplies are
+     *           stable; the board's external pull-down already holds RSTB during
+     *           rail ramp before app_main runs.
     *
     * @dname    boot
     * @param    band  DAB or FM application to load.