application: add auto-shutdown

application.c

@@ -69,6 +69,9 @@ static time_t time_start = 0;
 volatile bool rtc_internal_tick_flag = false; /**< flag set when internal RTC ticked */
 /** @} */
 
+/** activity timeout before switching off (in seconds) */
+#define SHUTDOWN_TIMEOUT 60
+
 size_t putc(char c)
 {
 	size_t length = 0; // number of characters printed
@@ -1040,25 +1043,44 @@ void main(void)
 	rcc_periph_clock_enable(RCC_GPIOG); // enable clock to all GPIO port domains since we use them all
 	usb_pins_float(); // pull all pins to floating
 
+	// find cable after power up
+	command_find("lcd");
+
 	// setup terminal
 	terminal_prefix = ""; // set default prefix
 	terminal_process = &process_command; // set central function to process commands
 	terminal_setup(); // start terminal
 
 	// start main loop
+	uint32_t last_connect_time = rtc_get_counter_val(); // last time a USB cable has been connected/disconnected
+	bool interactive = false; // if there is user activity on the serial port
 	bool action = false; // if an action has been performed don't go to sleep
 	while (true) { // infinite loop
 		iwdg_reset(); // kick the dog
 		if (user_input_available) { // user input is available
 			action = true; // action has been performed
-			//led_toggle(); // toggle LED
+			if (!interactive) { // the user takes control
+				interactive = true; // remember to not shut down anymore
+				// show interactive mode on LCD
+				const char* lcd_interactive_line1 = "interactive mode";
+				const char* lcd_interactive_line2 = "over serial port";
+				lcd_hd44780_clear_display();
+				lcd_hd44780_write_line(false, lcd_interactive_line1, strlen(lcd_interactive_line1));
+				lcd_hd44780_write_line(true, lcd_interactive_line2, strlen(lcd_interactive_line2));
+			}
 			char c = user_input_get(); // store receive character
 			terminal_send(c); // send received character to terminal
 		}
 		if (rtc_internal_tick_flag) { // the internal RTC ticked
 			rtc_internal_tick_flag = false; // reset flag
 			action = true; // action has been performed
-			//led_toggle(); // toggle LED (good to indicate if main function is stuck)
+			while (!interactive && rtc_get_counter_val() >= last_connect_time + SHUTDOWN_TIMEOUT) { // time to shut down
+				display_off(); // cut power to displays (at stop D+ pull-up to indicate disconnect)
+				SCB_SCR |= SCB_SCR_SLEEPDEEP; // Cortex-M3 standby setting
+				pwr_set_standby_mode(); // power setting
+				pwr_clear_wakeup_flag(); // clear wake-up flag to be able to sleep
+				__WFI(); // go to standby (e.g. shut down)
+			}
 		}
 		if (action) { // go to sleep if nothing had to be done, else recheck for activity
 			action = false;