DS1689S+T&R Maxim Integrated, DS1689S+T&R Datasheet - Page 21

• Manufacturer Part Number: DS1689S+T&R
• Description: Real Time Clock
• Manufacturer: Maxim Integrated
• Series: DS1689, DS1693r

Specifications of DS1689S+T&R

• Rohs: yes
• Function: Clock, Calendar, NV SRAM Control
• Rtc Bus Interface: Multiplexed
• Date Format: DW
• Time Format: HH
• Rtc Memory Size: 114 B
• Supply Voltage - Max: 5.5 V
• Supply Voltage - Min: 2.7 V
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-28

EXTENDED CONTROL REGISTERS
Two extended control registers are provided to supply controls and status information for the extended
features offered by the DS1689/DS1693. These are designated as extended control registers A and B and
are located in register bank 1, locations 04AH and 04BH, respectively. The functions of the bits within
these registers are described as follows.
Extended Control Register 4A
MSB
*
Bit 7: VRT2. This status bit gives the condition of the auxiliary battery. It is set to a logic 1 condition
when the external lithium battery is connected to the V
battery should be replaced.
Bit 6: INCR (Increment in Progress Status). This bit is set to 1 when an increment to the time/date
registers is in progress and the alarm checks are being made. INCR is set to 1 at 122µs before the update
cycle starts and is cleared to 0 at the end of each update cycle.
Bit 4: PAB (Power Active Bar Control). When this bit is 0, the PWR pin is in the active-low state. The
user can write this bit to logic 1 or logic 0. If either [WF and WIE = 1] or [KF and KSE = 1], the PAB bit
is cleared to 0.
Bit 2: RF (RAM Clear Flag). This bit is set to logic 1 when a high-to-low transition occurs on the RCLR
input if RCE = 1. The RF bit is cleared by writing it to logic 0. This bit can also be written to logic 1 to
force an interrupt condition.
Bit 1: WF (Wake-Up Alarm Flag). This bit is set to 1 when a wake-up alarm condition occurs or when
the user writes it to 1. WF is cleared by writing it to 0.
Bit 0: KF (Kickstart Flag). This bit is set to 1 when a kickstart condition occurs or when the user writes
it to 1. This bit is cleared by writing it to logic 0.
Reserved bits. These bits are reserved for future use by Dallas Semiconductor. They can be read and written, but have no effect on
operation.
BIT 7
VRT2
BIT 6
INCR
BIT 5
*
BIT 4
*
21 of 36
BIT 3
PAB
BAUX
. If this bit is read as logic 0, the external
BIT 2
RF
BIT 1
WF
BIT 0
KF
LSB