Microchip Technology IC MCU 8BIT PIC18F65K22-I/PT TQFP-64 MCP PIC18F65K22-I/PT Data Sheet

Product codes
PIC18F65K22-I/PT
Page of 550
 2009-2011 Microchip Technology Inc.
DS39960D-page 237
PIC18F87K22 FAMILY
18.1.4
RTCEN BIT WRITE
RTCWREN (RTCCFG<5>) must be set before a write
to RTCEN can take place. Any write to the RTCEN bit,
while RTCWREN = 0, will be ignored.
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.
18.2
Operation
18.2.1
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 18-2:
TIMER DIGIT FORMAT 
FIGURE 18-3:
ALARM DIGIT FORMAT 
0-6
0-9
0-9
0-3
0-9
0-9
0-9
0-9
0-2
0-5
0-5
0/1
Day of Week
Year
Day
Hours
(24-hour format)
Minutes
Seconds
1/2 Second Bit
0-1
0-9
Month
(binary format)
0-6
0-3
0-9
0-9
0-9
0-9
0-2
0-5
0-5
Day of Week
Day
Hours
(24-hour format)
Minutes
Seconds
0-1
0-9
Month