NXP Semiconductors OM11059UL, Руководство пользователя, Страница: 9 / 16

NXP Semiconductors
UM10699
User manual for SPI-bus RTC demoboard OM11059UL
UM10699 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2020. All rights reserved.
User manual Rev. 3 — 18 August 2020
9 / 16
4.2 System testing
There is a fast mode facility to test the functionality of the RTC; it can be activated by
setting the EXT_TEST bit in the Control_1 word.
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
Table 6. Setting the clock to 3.45 pm February 14, 2015
Name Address Setting
CE chip enable
Register address 0000 0000 address pointer to status word 0
0000 0011 set 12 hour mode and select option for
12.5 pF quartz
Status word 0
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 0100 14th day of month
Weekdays 0000 0110 Saturday (6th day of the week)
Month 0000 0010 February
Year 0001 0101 (20)15
CE chip disable
4.3.2 Reading the clock
Table 7. Reading the clock (2 minutes after writing)
Name Address Setting
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)