DS1673 Datasheet, PDF (4/18 Pages) Dallas Semiconductor – Portable System Controller

DS1673
POWER-UP/POWER-DOWN CONSIDERATIONS
When V_CC is applied to the DS1673 and reaches a level greater than V_CCTP (power-fail trip point), the
device becomes fully accessible after t_RPU (250ms typical). Before t_RPU elapses, all inputs are disabled.
When V_CC drops below V_CCSW, the device is switched over to the V_BAT supply.
During power-up, when V_CC returns to an in-tolerance condition, the RST pin is kept in the active state
for 250ms (typical) to allow the power supply and microprocessor to stabilize.
ADDRESS/COMMAND BYTE
The command byte for the DS1673 is shown in Figure 2. Each data transfer is initiated by a command
byte. Bits 0 through 6 specify the address 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 one. The address map for the DS1673 is
shown in Figure 3.
ADDRESS/COMMAND BYTE Figure 2
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