DS1852

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DIGITAL INPUTS

these inputs are mirrored in the “logic states” byte (6Eh) in Table 00h.

2-WIRE OPERATION

Clock and Data Transitions

The SDA pin is normally pulled high with an external resistor or device. Data on the SDA pin may only

change during SCL low time periods. Data changes during SCL high periods will indicate a start or stop

conditions depending on the conditions discussed below. See Figure 2 for further details.

Start Condition

A high-to-low transition of SDA with SCL high is a start condition that must precede any other

command. See Figure 2 for further details.

Stop Condition

A low-to-high transition of SDA with SCL high is a stop condition. After a read sequence, the stop

command places the DS1852 into a low-power mode. See Figure 2 for further details.

Acknowledge Bit

All address bytes and data bytes are transmitted through a serial protocol. The DS1852 pulls SDA low

during the ninth clock pulse to acknowledge that it has received each word.

Standby Mode

The DS1852 features a low-power mode that is automatically enabled after power-on, after a stop

command, and after the completion of all internal operations.

2-Wire Interface Reset

After any interruption in protocol, power loss, or system reset, the following steps reset the DS1852:

1) Clock up to nine cycles.

2) Look for SDA high in each cycle while SCL is high.

3) Create a start condition while SDA is high.

Device Addressing

The DS1852 must receive an 8-bit device address word following a start condition to enable a specific

device for a read or write operation. The address word is clocked into the DS1852 MSB to LSB. The

address word defaults to A0h then the R/W (READ/WRITE) bit when ASEL is a logic zero. If the R/W

bit is high, a read operation is initiated. If R/W is low, a write operation is initiated. The device address

is changed to the internal chip address (Table 03h address D0h) when ASEL is logic one. The default

internal chip address from the factory is A2h.