I'm usig a SiLabs 'F065 in a project, and on the same board, I have a sensor that has an expiration date. I have a space way up at the end of the CODE area reserved to hold the date that the sensor was put in service:
Global code unsigned char inserv[5+1] _at_ 0xFBF0; /* holds my inservice date */
CODE 0000H 0003H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0000H 0006H ABSOLUTE * OVERLAP * CODE 0003H 0003H ABSOLUTE CODE 0006H 0001H UNIT ?PR?UART2_ISR?UNUSED_ISR CODE 0007H 0001H UNIT ?PR?EXT_INT1_ISR?UNUSED_ISR CODE 0008H 0001H UNIT ?PR?TIMER1_ISR?UNUSED_ISR CODE 0009H 0001H UNIT ?PR?TIMER2_ISR?UNUSED_ISR CODE 000AH 0001H UNIT ?PR?SMB_ISR?UNUSED_ISR