pcf8564a NXP Semiconductors, pcf8564a Datasheet - Page 9

• Manufacturer Part Number: pcf8564a
• Description: Real Time Clock And Calendar
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCF8564A_1
Product data sheet
8.4.1.1 Voltage low detector and clock monitor
8.4.1 Register Seconds
8.4 Time and date registers
The majority of the registers are coded in the BCD format to simplify application use.
Table 8.
[1]
Table 9.
The PCF8564A has an on-chip voltage low detector. When V
(Voltage Low) flag is set to indicate that the integrity of the clock information is no longer
guaranteed. The VL flag can only be cleared by using the interface.
Bit
7
6 to 4 SECONDS 0 to 5
3 to 0
Seconds value in
decimal
00
01
02
:
09
10
:
58
59
Fig 5.
Start-up value.
Symbol
VL
Voltage low detection
Seconds - seconds and clock integrity status register (address 02h) bit
description
Seconds coded in BCD format
Value
0
1
0 to 9
Upper-digit (ten’s place)
Bit 6
0
0
0
0
0
1
1
[1]
Rev. 1 — 8 October 2009
V
V
DD
low
Place value Description
-
-
ten’s place
unit place
Bit 5
0
0
0
0
0
0
0
period of battery
operation
Bit 4
0
0
0
0
1
1
1
clock integrity is guaranteed
integrity of the clock information is not guaranteed
actual seconds coded in BCD format, see
VL set
Digit (unit place)
Bit 3
0
0
0
1
0
1
1
normal power
operation
mgr887
Real time clock and calendar
Bit 2
0
0
0
0
0
0
0
t
DD
drops below V
PCF8564A
Bit 1
0
0
1
0
0
0
0
© NXP B.V. 2009. All rights reserved.
low
Table 9
Bit 0
0
1
0
1
0
0
1
the VL
9 of 44