DS1670 Maxim, DS1670 Datasheet - Page 4

• Manufacturer Part Number: DS1670
• Description: The DS1670 portable system controller is a circuit that incorporates many of the functions necessary for low-power portable products integrated into one chip
• Manufacturer: Maxim

POWER-UP/POWER-DOWN CONSIDERATIONS
The DS1670 was designed to operate with a power supply of 3.3V. When 3.3V are applied within
nominal limits, the device becomes fully accessible after t
inputs are disabled. When V
below the lower of 2.7V (typical) or the battery voltage, the device is switched over to the backup power
supply.
During power-up, when V
for 250ms (typical) to allow the power supply and microprocessor to stabilize.
ADDRESS/COMMAND BYTE
The command byte for the DS1670 is shown in Figure 2. Each data transfer is initiated by a command
byte. Bits 0 through 6 specify the addresses of the registers to be accessed. The MSB (bit 7) is the
Read/Write bit. This bit specifies whether the accessed byte will be read or written. A read operation is
selected if bit 7 is a 0 and a write operation is selected if bit 7 is a 1. The address map for the DS1670 is
shown in Figure 3.
ADDRESS/COMMAND BYTE Figure 2
DS1670 ADDRESS MAP Figure 3
RD
0A
0D
0B
0C
0E
00
01
02
03
04
05
06
07
08
09
0F
7F
WR
7
BIT 7
M
M
M
M
0
0
0
0
0
0
A6
6
12
12
0
0
0
0
24
24
A5
10 YEAR
10 MIN ALARM
10 SEC ALARM
5
10 SECONDS
10 MINUTES
10 HR
10 HR
A/P
A/P
A4
WATCHDOG REGISTER
0
0
0
CC
10 DATE
4
CONTROL REGISTER
STATUS REGISTER
CC
returns to an in-tolerance condition, the RST pin is kept in the active state
ADC REGISTER
drops below 2.88V (typical), the RST pin is driven low. When V
A3
RESERVED
10 HR
10 HR
3
MO.
10
0
0
A2
2
0
A1
SECONDS ALARM
MINUTES ALARM
1
HOUR ALARM
DAY ALARM
4 of 16
SECONDS
MINUTES
MONTH
HOURS
YEAR
DATE
A0
0
DAY
RPU
(250ms typical). Before t
BIT 0
RPU
elapses, all
CC
DS1670
drops