CurrentRanger_R3: add display of configured logging format

The logging format is preserved in EEPROM, but never displayed, so you
can see the selected value only by changing it.  Add it to the set of
preferences that are displayed in the config/calib block.

Also start marking the key documentation for things that are
"preferences" that are saved between restarts.

Signed-off-by: Peter A. Bigot <pab@pabigot.com>

Author: pabigot

CurrentRanger_R3.ino

@@ -115,6 +115,13 @@ Adafruit_FreeTouch qt[3] = {
 //***********************************************************************************************************
 #define PREFERENCE_MU_SAMPLERATE 0x01  // default BIAS
 //***********************************************************************************************************
+static const char *const loggingFormat_str[] = {
+  [LOGGING_FORMAT_EXPONENT] = "exp (1.23E-3 = 123 mA)",
+  [LOGGING_FORMAT_NANOS] = "nA (1234 = 1.234 uA)",
+  [LOGGING_FORMAT_MICROS] = "uA (1234 = 1.234 mA)",
+  [LOGGING_FORMAT_MILLIS] = "mA (1234 = 1.234 A)",
+  [LOGGING_FORMAT_ADC] = "adc (0..4095)",
+};
 int offsetCorrectionValue = 0;
 uint16_t gainCorrectionValue = 0;
 float ldoValue = 0, ldoOptimized=0;
@@ -477,11 +484,7 @@ void loop()
       case 'f': //cycle through output logging formats
         if (++LOGGING_FORMAT>LOGGING_FORMAT_ADC) LOGGING_FORMAT=LOGGING_FORMAT_EXPONENT;
         eeprom_LOGGINGFORMAT.write(LOGGING_FORMAT);
-        if (LOGGING_FORMAT==LOGGING_FORMAT_EXPONENT) Serial.println("LOGGING_FORMAT_EXPONENT"); else
-        if (LOGGING_FORMAT==LOGGING_FORMAT_NANOS) Serial.println("LOGGING_FORMAT_NANOS"); else
-        if (LOGGING_FORMAT==LOGGING_FORMAT_MICROS) Serial.println("LOGGING_FORMAT_MICROS"); else
-        if (LOGGING_FORMAT==LOGGING_FORMAT_MILLIS) Serial.println("LOGGING_FORMAT_MILLIS"); else
-        if (LOGGING_FORMAT==LOGGING_FORMAT_ADC) Serial.println("LOGGING_FORMAT_ADC");
+        Serial.println(loggingFormat_str[LOGGING_FORMAT]);
         break;
       case 'a': //toggle autoOff function
         if (AUTOFF_INTERVAL == AUTOFF_DEFAULT)
@@ -895,6 +898,7 @@ void printCalibInfo() {
   Serial.print("Gain="); Serial.println(gainCorrectionValue);
   Serial.print("LDO="); Serial.println(ldoValue,3);
   Serial.print("SampleRate: "); sampleRateOutSerial();
+  Serial.print("LogFmt: "); Serial.println(loggingFormat_str[LOGGING_FORMAT]);
   Serial.print("uA+mA: ");
   Serial.println((PREFERENCES & PREFERENCE_MU_SAMPLERATE)
           ? "toggle samplerate adjust"
@@ -904,9 +908,9 @@ void printSerialMenu() {
   Serial.println("\r\nUSB serial commands:");
   Serial.println("a = toggle Auto-Off function");
   Serial.print  ("b = toggle BT/serial logging (");Serial.print(SERIAL_UART_BAUD);Serial.println("baud)");
-  Serial.println("f = cycle serial logging formats (exponent,nA,uA,mA/raw-ADC)");
+  Serial.println("f = cycle serial logging formats (exponent,nA,uA,mA/raw-ADC) [PREF]");
   Serial.println("g = toggle GPIO range indication (SCK=mA,MISO=uA,MOSI=nA)");
-  Serial.println("o = toggle touchpad offset (bias) / samplerate selection");
+  Serial.println("o = toggle touchpad offset (bias) / samplerate selection [PREF]");
   Serial.println("t = toggle touchpad serial output debug info");
   Serial.println("u = toggle USB/serial logging");
   Serial.println("+ = increase mode value");