From caed09f4db0fd329d0167ddf18be8fa429d68e33 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Wed, 24 Mar 2021 00:46:30 +0100
Subject: [PATCH] application: add command to set/show target voltage

---
 application.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 75 insertions(+), 1 deletion(-)

diff --git a/application.c b/application.c
index f896592..a42fe6b 100644
--- a/application.c
+++ b/application.c
@@ -11,6 +11,7 @@
 #include <string.h> // string utilities
 #include <time.h> // date/time utilities
 #include <ctype.h> // utilities to check chars
+#include <math.h> // rounding utilities
 
 /* STM32 (including CM3) libraries */
 #include <libopencmsis/core_cm3.h> // Cortex M3 utilities
@@ -88,6 +89,30 @@ size_t putc(char c)
 	return length; // return number of characters printed
 }
 
+/** print float with fixed precision
+ *  @param[in] fpu float to print
+ *  @param[in] precision number of digits after comma to print
+ *  @note %f is used to force scientific notation
+ */
+static void print_fpu(double fpu, uint8_t precision)
+{
+	uint32_t multiplier = 1;
+	for (uint8_t i = 0; i < precision; i++) {
+		multiplier *= 10;
+	}
+	double to_print = round(fpu * multiplier);
+	printf("%d.", (int32_t)to_print / multiplier);
+	char decimal[32];
+	snprintf(decimal, LENGTH(decimal), "%u", abs(to_print) % multiplier);
+	if (strlen(decimal) > precision) {
+		decimal[precision] = 0;
+	}
+	for (uint8_t i = strlen(decimal); i < precision; i++) {
+		putc('0');
+	}
+	puts(decimal);
+}
+
 /** get RCC from corresponding port
  *  @param[in] port port address
  *  @return RCC address corresponding to port
@@ -179,6 +204,47 @@ static void mux_select(int8_t channel)
 
 // menu commands
 
+/** measure and print target voltage
+ *  @param[in] argument 0 to no provide power, 3 to provide 3.3V
+ */
+static void command_target_voltage(void* argument)
+{
+	(void)argument; // we won't use the argument
+
+	// set voltage
+	if (argument) { // if argument is provided
+		const uint8_t voltage = *(uint32_t*)argument; // get target voltage
+		switch (voltage) {
+		case 0:
+			gpio_set(GPIO_PORT(TARGET_3V_PIN), GPIO_PIN(TARGET_3V_PIN)); // disable 3V output
+			break;
+		case 3:
+			gpio_clear(GPIO_PORT(TARGET_3V_PIN), GPIO_PIN(TARGET_3V_PIN)); // enable 3V output
+			break;
+		default:
+			puts("unknown voltage to set\n");
+			break;
+		}
+		sleep_us(100); // wait a bit for voltage to settle
+	}
+
+	// show voltage output
+	if (!gpio_get(GPIO_PORT(TARGET_3V_PIN), GPIO_PIN(TARGET_3V_PIN))) {
+		puts("target voltage set to 3.3 V\n");
+	} else {
+		puts("target voltage externally provided\n");
+	}
+
+	float* voltages = measure_voltages(); // measure voltages
+	puts("target voltage: ");
+	print_fpu(voltages[1], 2);
+	puts(" V");
+	if (voltages[1] < 1.0) {
+		puts(" (warning: target voltage seems not connected)");
+	}
+	putc('\n');
+}
+
 /** display available commands
  *  @param[in] argument no argument required
  */
@@ -383,7 +449,7 @@ static const struct menu_command_t menu_commands[] = {
 		.command_handler = &command_help,
 	},
 	{
-		.shortcut = 'v',
+		.shortcut = 'V',
 		.name = "version",
 		.command_description = "show software and hardware version",
 		.argument = MENU_ARGUMENT_NONE,
@@ -430,6 +496,14 @@ static const struct menu_command_t menu_commands[] = {
 		.argument_description = NULL,
 		.command_handler = &command_bootloader,
 	},
+	{
+		.shortcut = 'v',
+		.name = "voltage",
+		.command_description = "set/measure target voltage",
+		.argument = MENU_ARGUMENT_UNSIGNED,
+		.argument_description = "[0|3|5]",
+		.command_handler = &command_target_voltage,
+	},
 };
 
 static void command_help(void* argument)