Menu freezes UNO hard

Projects Programming
1

For some reason this particular function will cause the uno to lock up as in everything stopping functioning and some strings returned to serial are garbage just before freeze. I narrowed it down to here by commenting out call and finding it works fine when bypassed. I can't post whole code as it's too long.

void menuM1() {
  char lcdOut0[20];
  char lcdOut1[20];
  char timeM[4][20] = { {"Time Set"}, {"Auto/NTP Time Set"}, {"Temp Timeout"}, {"Fan Timeout."} };
  char scheduleM[4][20] =  { {"Set # of blocks"}, {"Select Block"}, {"Set block time"}, {"Set block Temp"}};
  char fanM[4][20] = { {"On with H/C"}, {"On all time"}, {"Post-mix..."}, {"On Every..."} };
  char tempM[4][20] = { {"Hysteresis"}, {"Temp. Alerts"}, {"."}};
  char lockM[4][20] = { {"Lock On/Off"} , { "Lock Timeout" }, { '.' }, { '.' }};
  switch (menuIDa) {
    case 0: //Time Menu
      strncpy(lcdOut0, timeM[menuIndex], 20);
      strncpy(lcdOut1, timeM[menuIndex + 1], 20);
      break;
    case 1: //Schedule Menu
      strncpy(lcdOut0, scheduleM[menuIndex], 20);
      strncpy(lcdOut1, scheduleM[menuIndex + 1], 20);
      break;
    case 2: //Fan Menu
      strncpy(lcdOut0, fanM[menuIndex], 20);
      strncpy(lcdOut1, fanM[menuIndex + 1], 20);
      break;
    case 3: //Lock Menu
      strncpy(lcdOut0, lockM[menuIndex], 20);
      strncpy(lcdOut1, lockM[menuIndex + 1], 20);
    case 4: //Temperature Menu
      strncpy(lcdOut0, tempM[menuIndex], 20);
      strncpy(lcdOut1, tempM[menuIndex + 1], 20);
      break;
  }
  Serial.print('*');
  Serial.println(lcdOut0);
  Serial.println(lcdOut1);
  Serial.println("----------");
}
2

That throws at least 440 bytes on the stack. You think you've got enough memory?

3

I'm getting close. I think I need more than an Uno for this thermostat project. I tend to over-use globals, but I use functions that need to share any number of vars. I comment out a lot of global but the usage never goes down. Funny thing is I comment out the function in question, global var usage drops.

Sketch uses 15344 bytes (47%) of program storage space. Maximum is 32256 bytes.
Global variables use 1406 bytes (68%) of dynamic memory, leaving 642 bytes for local variables. Maximum is 2048 bytes.

Here are my global declares:

int currentMM, currentHH;
int HHOffset, MMOffset, cursorPosition = 0, menuIndex = 0, menuIDa = 0, menuIDb, menuIDc, menuDepth = 0;
int millisPrior, subLoop, tempReadI, locked, seed, scheduleHH, scheduleMM, scheduleTemp, tempSetting, currentTemp, systemOnMS, systemPrev;
int ntpOn;
int flasherA[5][7] = { 0 };
unsigned long menuStartMS, flasherL[5];
char* lcdMode, currentBlock;
//float tempRounded = 70.5;
String currentTimeStr, modeName;


// PIN-MAP
//*****************************************************************************************************************************************************************
// -1: InputPullup, 0: Not installed, 1: Input Positive, 2: OUTPUT
int installed[20] = {   0,  0,   2,      2,    2,     0,    2,    0,    0,     2,     2,     2,    1,      0,    1,     0,      0,    0,     0,          0 };
char* pinNames[20] = { '0', '1', '2',   '3',   '4',   '5', '6', '7',   '8',   '9',  "10",  "11", "12",  "13",  "A0",  "A1",  "A2",  "A3",  "A4",      "A5"  };
char* ssNames[20] = {  "x", "x", "FN6", "HT6", "AC6", "x", "LB6", "x", "x", "LO6", "LR6", "LG6",  "tm6", "LED",   "sd6", "x", "x", "x", "x", "x" };
const int                       FN6 = 2,     AC6 = 4,     LB6 = 6,                         LG6 = 11,     LED = 13,       sd6 = A0     ;
const int                             HT6 = 3,                          LO6 = 9, LR6 = 10,      tm6 = 12      ;
// *****************************************************************************************************************************************************************
4

All of these character constants can be stored in flash memory, instead of wasting precious RAM.

 char timeM[4][20] = { {"Time Set"}, {"Auto/NTP Time Set"}, {"Temp Timeout"}, {"Fan Timeout."} };