@PJ_GLass I very much appreciate the help. However, I fear we are in jeopardy of going around in circles. You rightly point out the C3 needs to use the esp_deep_sleep_enable_gpio_wakeup() function…which is what I am using. However, your example code then uses esp_sleep_enable_ext0_wakeup((gpio_num_t)BUTTON_PIN, HIGH); ???
And I know I am sounding like a broken record but the problem has never been waking up the ESP with a simple button. That’s a piece of cake. The issue is using an array of buttons that are connected in a matrix.
In that scenario a single button does not go high or low. Rather, when a button is pressed an impedance of about 200 ohms appears between the corresponding column pin and row pin.
As mentioned, as much as I hate to give up, I just can’t see a way to get the keypad to wakeup the ESP32C3.