Changes

This is the technical application manual for the 72421 RTC chip used in uRTC-8.Of particular interest are the registers.  RTCBASE .equ 0A0h ; Default uRTC base I/O address rtc1sec .db RTCBASE+00h ; 1 second digit rtc10sec .db RTCBASE+01h ; 10 second digit rtc1min .db RTCBASE+02h ; 1 minute digit rtc10min .db RTCBASE+03h ; 10 minute digit rtc1hour .db RTCBASE+04h ; 1 hour digit rtc10hour .db RTCBASE+05h ; 10 hour digit (also AM/PM indicator) rtc1day .db RTCBASE+06h ; 1 day digit rtc10day .db RTCBASE+07h ; 10 day digit rtc1month .db RTCBASE+08h ; 1 month digit rtc10month .db RTCBASE+09h ; 10 month digit rtc1year .db RTCBASE+0Ah ; 1 year digit rtc10year .db RTCBASE+0Bh ; 10 year digit rtcweek .db RTCBASE+0Ch ; day of week rtccrtlD .db RTCBASE+0Dh ; control register D rtcctrlE .db RTCBASE+0Eh ; control register E rtcctrlF .db RTCBASE+0Fh ; control register F