Can't assign values to array I just made.

I am confident those variables haven't been optimized out because in the compiler I set the optimization level to 0, "No optimization". I also use the variables later in the function to hold a string, then send the buffer to atoi to convert it into an integer that is then used to update the real-time clock.

If I change my local arrays to static arrays, then the function will work. If I remove the static keyword, then the function hangs on the first read from local array.

This code is working:

int SetRTC(char *cmd)
{
  static const s8 RTC_MIN[6] = {  0,  0,  0,  1,  1,  9 };
  static const s8 RTC_MAX[6] = { 59, 59, 23, 31, 12, 99 };
  static const s8 MONTH_TO_DAY[12] = { 31, 28, 31, 30, 31, 30,
                                       31, 31, 30, 31, 30, 31 };

  // Variables
  s8  i       = 0;
  s32 TimeVar = 0;
  static s8 buff[4];
  static s8 Time[6];   // { ss, mm, hh, dd, MM, yy }

  // Parse command string
  for(i = 0; i < 6; i++)
  {
    // If buff is NOT a static array:
    //TimeVar = 0;        // Works fine
    //buff[0] = 10;       // Doesn't change buff[0], but doesn't cause program to hang
    //TimeVar = buff[1];  // Causes program to hang

    memset(buff, 0, sizeof(buff));  // Clear the buffer

    memcpy(buff, cmd + (i * 2), 2);  // Copy two digits from command to buffer

    Time[i] = atoi(buff);         // Convert buffer to ineger

    if ((Time[i] < RTC_MIN[i]) || // Check min/max values
        (Time[i] > RTC_MAX[i]))
    {
      printf("\r\nbad RTC date"); // Display error message
      return No_Commands_Run;     // Return without setting RTC
    }
  }

  // Verify the specified month actually has the specified days
  if (MONTH_TO_DAY[Time[4]] < Time[3])
  {
    if ((Time[4] == 2) && (Time[3] == 29) && (Time[5] % 4 == 0))
    {
      // February 29th of a leap year, not an error
    }
    else
    {
      printf("\r\nbad RTC date");   // Display error message
      return No_Commands_Run;       // Return without setting RTC
    }
  }

  // Calculate the easy ones:
  TimeVar = Time[0]             +  // Seconds
            Time[1]      * 60   +  // Minutes
            Time[2]      * 3600 +  // Hours
           (Time[3] - 1) * 86400;  // Days

  // Add days for earlier months in the year
  for (i = Time[4] - 1; i >= 0; i--)
    TimeVar += MONTH_TO_DAY[i];

  // Add years for previous years since 2000;
  TimeVar += Time[5] * 365 * 86400;

  // Add leap days
  if(Time[4] <= 2)  // If it is Jan or Feb, hold back a year (see next comments)
    TimeVar += ((Time[5] + 3) / 4) * 86500;   // 2000 = +0 leap days
  else
    TimeVar += ((Time[5] + 4) / 4) * 86500;   // 2000 = +1 leap day

  // Set the clock
  RTC_SetCounter(TimeVar); // Set RTC
        RTC_WaitForLastTask();   // Wait for command to complete

  // TODO: Remove after testing
  ReadRTC();

  return Single_Command;
}

I am confident those variables haven't been optimized out because in the compiler I set the optimization level to 0, "No optimization". I also use the variables later in the function to hold a string, then send the buffer to atoi to convert it into an integer that is then used to update the real-time clock.

If I change my local arrays to static arrays, then the function will work. If I remove the static keyword, then the function hangs on the first read from local array.

This code is working:

int SetRTC(char *cmd)
{
  static const s8 RTC_MIN[6] = {  0,  0,  0,  1,  1,  9 };
  static const s8 RTC_MAX[6] = { 59, 59, 23, 31, 12, 99 };
  static const s8 MONTH_TO_DAY[12] = { 31, 28, 31, 30, 31, 30,
                                       31, 31, 30, 31, 30, 31 };

  // Variables
  s8  i       = 0;
  s32 TimeVar = 0;
  static s8 buff[4];
  static s8 Time[6];   // { ss, mm, hh, dd, MM, yy }

  // Parse command string
  for(i = 0; i < 6; i++)
  {
    // If buff is NOT a static array:
    //TimeVar = 0;        // Works fine
    //buff[0] = 10;       // Doesn't change buff[0], but doesn't cause program to hang
    //TimeVar = buff[1];  // Causes program to hang

    memset(buff, 0, sizeof(buff));  // Clear the buffer

    memcpy(buff, cmd + (i * 2), 2);  // Copy two digits from command to buffer

    Time[i] = atoi(buff);         // Convert buffer to ineger

    if ((Time[i] < RTC_MIN[i]) || // Check min/max values
        (Time[i] > RTC_MAX[i]))
    {
      printf("\r\nbad RTC date"); // Display error message
      return No_Commands_Run;     // Return without setting RTC
    }
  }

  // Verify the specified month actually has the specified days
  if (MONTH_TO_DAY[Time[4]] < Time[3])
  {
    if ((Time[4] == 2) && (Time[3] == 29) && (Time[5] % 4 == 0))
    {
      // February 29th of a leap year, not an error
    }
    else
    {
      printf("\r\nbad RTC date");   // Display error message
      return No_Commands_Run;       // Return without setting RTC
    }
  }

  // Calculate the easy ones:
  TimeVar = Time[0]             +  // Seconds
            Time[1]      * 60   +  // Minutes
            Time[2]      * 3600 +  // Hours
           (Time[3] - 1) * 86400;  // Days

  // Add days for earlier months in the year
  for (i = Time[4] - 1; i >= 0; i--)
    TimeVar += MONTH_TO_DAY[i];

  // Add years for previous years since 2000;
  TimeVar += Time[5] * 365 * 86400;

  // Add leap days
  if(Time[4] <= 2)  // If it is Jan or Feb, hold back a year (see next comments)
    TimeVar += ((Time[5] + 3) / 4) * 86500;   // 2000 = +0 leap days
  else
    TimeVar += ((Time[5] + 4) / 4) * 86500;   // 2000 = +1 leap day

  // Set the clock
  RTC_SetCounter(TimeVar); // Set RTC
        RTC_WaitForLastTask();   // Wait for command to complete

  // TODO: Remove after testing
  ReadRTC();

  return Single_Command;
}

What do you mean by "Does not work"?

Are you indicating the value is not zero in those locations? Or is that statement not getting executed?

Does the following "work" for you?

 s8 buff_1[4];
  s8 buff_2[4] = { 7, 7, 7, 7 };

  buff_1[0] = 7;
  buff_1[1] = 7;
  buff_1[2] = 7;
  buff_1[3] = 7;

@Marc

No, that doesn't work either. What I mean is that when the arrays are created they have random values. If I try to initialize them their values don't change, they are still random values.

s8 buff_1[4];                   // Will have values like { 0x28, 0x32, 0x00, 0x00 }
s8 buff_2[4] = { 0, 0, 0, 0 };  // Doesn't work, buff_2 will still have random values

buff_1[0] = 0;    // Still shows up as it's initial value, not 0
buff_1[1] = 1;    // Still shows up as it's initial value, not 1
buff_1[2] = 2;    // Still shows up as it's initial value, not 2
buff_1[3] = 3;    // Still shows up as it's initial value, not 3

if (buff_1[0] == 0)  // Debugger stops on this line. 'Step', 'step over',
{                    // and 'step into' don't leave this line
  ... // Do something
}

Hello,

This sounds strange to me. Are you doing anything 'different' with your memory or start-up?

For example where is your stack located?

Is the c-library properly initializing the ZI regions?

What does you s8 definition look like?

Are you using any 'special' compiler options? (like --c99?)

I think the arrays gets stored in non-existing RAM, while smaller data are stored on stack or in registers.

I think the arrays gets stored in non-existing RAM, while smaller data are stored on stack or in registers.

Does the OP run his program on a simulator or the real thing?