Configuration of RTC_C

Hi All,

I have designed a PCB that has a XT1 external 32.768KHz crystal attached across XIN & XOUT with two 12pF caps.

I am trying to configure the RTC_C in software and I am struggling to write to the RTCSEC...RTCYEAR registers. When I step through them they don't get written, just stay at 0x00.

Here is my small configuration code;

RTCCTL0 |= RTCKEY;         //Password protection write 0xA5 (RTCKEY) to unlock

RTCCTL1 |= RTCBCD + RTCHOLD + RTCMODE;   //Sets Hex mode, halts RTC, Calendar Mode

  RTCSEC = 0x02;              
  RTCMIN = 0x1F;
  RTCHOUR = 0x0D;
  RTCDOW = 0x02;
  RTCDAY = 0x1B;
  RTCMON = 0x01;
  RTCYEAR = 0x7E0;
  
  RTCCTL1 &= ~RTCHOLD;       //starts RTC

Any help would be appreciated.