PIC18F87J90 Datasheet, PDF (165/450 Pages) Microchip Technology – 64/80-Pin, High-Performance Microcontrollers with LCD Driver and nanoWatt Technology

PIC18F87J90 FAMILY
15.1.4 RTCEN BIT WRITE
An attempt to write to the RTCEN bit while
RTCWREN = 0 will be ignored. RTCWREN must be
set before a write to RTCEN can take place.
Like the RTCEN bit, the RTCVALH and RTCVALL
registers can only be written to when RTCWREN = 1.
A write to these registers, while RTCWREN = 0, will be
ignored.
FIGURE 15-2:
TIMER DIGIT FORMAT
Year
Month
0-9
0-9
0-1
0-9
Hours
(24-hour format)
0-2
0-9
Minutes
0-5
0-9
15.2 Operation
15.2.1 REGISTER INTERFACE
The register interface for the RTCC and alarm values is
implemented using the Binary Coded Decimal (BCD)
format. This simplifies the firmware when using the
module as each of the digits is contained within its own
4-bit value (see Figure 15-2 and Figure 15-3).
Day
0-3
0-9
Seconds
0-5
0-9
Day Of Week
0-6
1/2 Second Bit
(binary format)
0/1
FIGURE 15-3:
ALARM DIGIT FORMAT
Month
Hours
(24-hour format)
0-2
0-9
0-1
0-9
Minutes
0-5
0-9
Day
0-3
0-9
Seconds
0-5
0-9
Day Of Week
0-6
 2010 Microchip Technology Inc.
DS39933D-page 165