NXP Semiconductors
UM10699
User manual for SPI-bus RTC demoboard OM11059
UM10699
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2013. All rights reserved.
User manual
Rev. 1 — 04 April 2013
7 of 12
The RTC PCF85063BTL has a frequency tuning facility; its operation is explained in
section 5.
The RTC can stay switched on all the time. There is no need to restart or reset the clock.
4.3 Software instructions for setting the clock
4.3.1 Setting the time
Setting the clock to 3.45 pm February 15, 2013,
•
CE
chip enable
•
Register address 0000 0000
address pointer to status word 0
•
Status word 0
0000 0011
set 12 hour mode and select option for
12.5 pF quartz
0000 0010 set 12 hour mode and select option for
7 pF quartz
•
CE
chip disable
•
CE
chip enable
•
Register address 0000 0100
address pointer to seconds register
•
Seconds
0000 0000
0 Seconds (clock integrity ok
MSB OS = 0)
•
Minutes
0100 0101
45 min
•
Hours
0010 0011
PM, 3 (clock integrity ok
OS = 0)
•
Days
0001 0101
15
th
•
Weekdays
0000 0101
Friday (5
th
day of the week)
•
Month
0001 0010
December
•
Year
0001 0011
(20)13
•
CE
chip disable
4.3.2 Reading the clock
•
Reading the clock (2 minutes after writing)
•
CE
chip enable
•
Register address 0000 0100
address pointer to seconds (R/W
¯¯ bit = 1)
•
Read register 4,
seconds
. . . . . . . .
e.g. 56 Seconds, (clock integrity ok
OS = 0)
•
Minutes
. . . . . . . .
e.g. 46 (Minutes)
•
Hours
. . . . . . . .
e.g. 03 (PM 03h)
•
Days
. . . . . . . .
e.g. 15 (15
th
)
•
Weekdays
. . . . . . . .
e.g. 05 (Friday)
•
Month
. . . . . . . .
e.g. 03 (March)
•
Year
. . . . . . . .
e.g. 13 (20)13
•
CE
chip disable