Battery Voltage

Readout/monitor battery voltage and turn off in case it gets too low. Also make the voltage available via API.

Partly implements #34.

epicardium/ble/ble.c

+#include "epicardium.h"
 #include "modules/log.h"
 
 #include "fs_util.h"
@@ -7,6 +8,7 @@
 #include "ble_api.h"
 #include "hci_vs.h"
 #include "att_api.h"
+#include "trng.h"
 
 #include "FreeRTOS.h"
 #include "timers.h"
@@ -92,8 +94,27 @@ static void setAddress(void)
 	uint8_t bdAddr[6] = { 0x02, 0x02, 0x44, 0x8B, 0x05, 0x00 };
 	char buf[32];
 
-	fs_read_text_file("mac.txt", buf, sizeof(buf));
-	APP_TRACE_INFO1("mac file contents: %s", buf);
+	int result = fs_read_text_file("mac.txt", buf, sizeof(buf));
+
+	if (result == -1) {
+		APP_TRACE_INFO0("mac.txt not found, generating random MAC");
+		bdAddr[0] = 0xCA;
+		bdAddr[1] = 0x4D;
+		bdAddr[2] = 0x10;
+		TRNG_Read(MXC_TRNG, bdAddr + 3, 3);
+		sprintf(buf,
+			"%02x:%02x:%02x:%02x:%02x:%02x\n",
+			bdAddr[0],
+			bdAddr[1],
+			bdAddr[2],
+			bdAddr[3],
+			bdAddr[4],
+			bdAddr[5]);
+		fs_write_file("mac.txt", buf, strlen(buf));
+	} else {
+		APP_TRACE_INFO1("mac file contents: %s", buf);
+	}
+
 	int a, b, c, d, e, f;
 	if (sscanf(buf, "%x:%x:%x:%x:%x:%x", &a, &b, &c, &d, &e, &f) == 6) {
 		bdAddr[0] = f;
@@ -152,6 +173,37 @@ void wsf_ble_signal_event(void)
 	notify();
 }
 /*************************************************************************************************/
+#define BLEMAXCFGBYTES 100
+bool ble_shall_start(void)
+{
+	int bleConfigFile = epic_file_open("ble.txt", "r");
+	if (bleConfigFile < 0) {
+		LOG_INFO("ble", "can not open ble.txt -> BLE is not started");
+		epic_file_close(bleConfigFile);
+		return false;
+	}
+
+	char cfgBuf[BLEMAXCFGBYTES + 1];
+	int readNum = epic_file_read(bleConfigFile, cfgBuf, BLEMAXCFGBYTES);
+	epic_file_close(bleConfigFile);
+	if (readNum < 0) {
+		LOG_WARN("ble", "can not read ble.txt -> BLE is not started");
+		return false;
+	}
+	cfgBuf[readNum] = '\0';
+
+	char bleActiveStr[]              = "active=true";
+	cfgBuf[sizeof(bleActiveStr) - 1] = '\0';
+
+	if (strcmp(cfgBuf, "active=true") != 0) {
+		LOG_INFO("ble", "BLE is disabled.");
+		return false;
+	} else {
+		LOG_INFO("ble", "BLE is enabled.");
+		return true;
+	}
+}
+/*************************************************************************************************/
 static void scheduleTimer(void)
 {
 	bool_t timerRunning;