DS2770

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FUNCTION COMMANDS Table 3

COMMAND

DESCRIPTION

COMMAND

PROTOCOL

BUS STATE AFTER

COMMAND

PROTOCOL

BUS DATA

Read Data

Reads data from

memory map starting

at address XX

69h, XX

Unlimited

Write Data

Writes data to memory

starting at address XX

6Ch, XX

Master Tx

Unlimited

Copy Data

Copies shadow RAM

data to EEPROM

block that begins with

address location XX

48h, XX

Master Reset

None

Recall Data

Recalls EEPROM

block that begins with

address location XX to

shadow RAM

B8h, XX

Master Reset

None

Lock

Permanently locks the

block of lockable

EEPROM memory

that begins with

address location XX

6Ah, XX

Master Reset

None

Refresh

Restores Status

Register initialization

data

63h

Master Reset

None

Start Charge

Initiates charge

through the host

interface.

B5h

Master Reset

None

Stop Charge

Terminates charge

through the host

interface.

BEh

Master Reset

None

I/O SIGNALING

The 1-Wire bus requires strict signaling protocols to insure data integrity. The DS2770 uses the following

four protocols: the initiation sequence (reset pulse followed by presence pulse), Write 0, Write 1, and

Read Data. All of these types of signaling except the presence pulse are initiated by the bus master.

Figure 18 shows the initialization sequence required to begin any communication with the DS2770. A

presence pulse following a reset pulse indicates the DS2770 is ready to accept a Net Address command.