Datasheet

Real Time Clock (RTC)
Data Sheet MC68HC908LJ24/LK24 — Rev. 2.1
244 Real Time Clock (RTC) Freescale Semiconductor
12.10.13 Day-Of-Week Register (DOWR)
This read/write register contains the current value of the day-of-week
counter. This register can be read at any time without affecting the
counter count. Writing to this register loads the value to the day-of-week
counter and the counter continues to count from this new value.
The day-of-week counter value rolls over to 0 ($00) after reaching 6
($06). Writing a value other than 0 to 6 to this register has no effect.
12.10.14 Chronograph Data Register (CHRR)
This read-only chronograph data register contains the value in the
chronograph counter. Reset clears the chronograph data register.
Setting the chronograph counter reset bit (CHRCLR) also clears the
chronograph data register.
The chronograph data register has a resolution of 1/100 seconds. The
chronograph counter value rolls over to $00 after reaching $63.
NOTE: The chronograph counter is not synchronized to the compensated RTC
1-Hz clock. Hence, chronograph ticks may not align with the RTC clock
and calendar register updates.
Address: $004D
Read: 00000
DOW2 DOW1 DOW0
Write:
Reset:00000UUU
= Unimplemented
This register is write-protected; unprotect by a write sequence to RTCWE[1:0] in RTCCOMR.
Figure 12-19. Day-Of-Week Register (DOWR)
Address: $004E
Read: 0 CHR6 CHR5 CHR4 CHR3 CHR2 CHR1 CHR0
Write:
Reset:00000000
= Unimplemented
Figure 12-20. Chronograph Data Register (CHRR)