PCF212311 데이터 시트보기 (PDF) - NXP Semiconductors.
부품명
상세내역
제조사
PCF212311 Datasheet PDF : 63 Pages
| |||
NXP Semiconductors
PCF2123
SPI Real time clock/calendar
8.4 Time and date function
The majority of the registers are coded in the Binary Coded Decimal (BCD) format. BCD is
used to simplify application use. An example is shown for the seconds in Table 9.
8.4.1 Register Seconds
Table 8. Seconds - seconds register (address 02h) bit description
Bit
Symbol
Value
Place value Description
7
OS
0
-
clock integrity is guaranteed
1[1]
-
clock integrity is not guaranteed;
oscillator has stopped or has
been interrupted
6 to 4 SECONDS
3 to 0
0 to 5
0 to 9
ten’s place actual seconds coded in BCD
unit place format, see Table 9
[1] Default value.
Table 9. Seconds coded in BCD format
Seconds value Upper-digit (ten’s place)
(decimal)
Bit 7 Bit 6 Bit 5
00
0
0
0
01
0
0
0
02
0
0
0
:
:
:
:
09
0
0
0
10
0
0
0
:
:
:
:
58
0
1
0
59
0
1
0
Bit 4
0
0
0
:
0
1
:
1
1
Digit (unit place)
Bit 3 Bit 2 Bit 1
0
0
0
0
0
0
0
0
1
:
:
:
1
0
0
0
0
0
:
:
:
1
0
0
1
0
0
Bit 0
0
1
0
:
1
0
:
0
1
8.4.1.1 OS flag
The PCF2123 includes a flag (OS in register Seconds, see Table 8) which is set whenever
the oscillator is stopped (see Figure 8 and Figure 9). The flag will remain set until cleared
by software. If the flag cannot be cleared, then the PCF2123 oscillator is not running. This
method can be used to monitor the oscillator and to determine if the supply voltage has
reduced to the point where oscillation fails.
VDD
battery operation
main supply
VOSC(MIN)
PCF2123
Product data sheet
Fig 8. OS set by failing VDD
All information provided in this document is subject to legal disclaimers.
Rev. 5 — 27 April 2011
t
001aai561
© NXP B.V. 2011. All rights reserved.
12 of 63
Share Link: 