DS2764 MAXIM [Maxim Integrated Products], DS2764 Datasheet - Page 19

• Manufacturer Part Number: DS2764
• Description: High-Precision Li+ Battery Monitor with 2-Wire Interface
• Manufacturer: MAXIM [Maxim Integrated Products]

Read Data Protocol
The Read Data protocol is used to read register and shadow RAM data from the DS2764 starting at memory
address specified by MAddr. Data0 represents the data byte in memory location MAddr, Data1 represents the data
from MAddr + 1 and DataN represents the last byte read by the master.
Data is returned beginning with the most significant bit (msb) of the data in MAddr. Because the address is
automatically incremented after the least significant bit (lsb) of each byte is returned, the msb of the data at
address MAddr + 1 is available to the host immediately after the acknowledgement of the data at address MAddr. If
the bus master continues to read beyond address FFh, the DS2764 outputs data values of FFh. Addresses labeled
“Reserved” in the memory map return undefined data. The bus master terminates the read transaction at any byte
boundary by issuing a No Acknowledge followed by a STOP or Repeated START.
Function Command Protocol
The Function Command protocol executes a device specific operation by writing one of the function command
values (FCmd) to memory address FEh. Table 4 lists the DS2764 FCmd values and describes the actions taken
by each. A one byte write protocol is used to transmit the function command, with the MAddr set to FEh and the
data byte set to the desired FCmd value. Additional data bytes are ignored. Data read from memory address FEh
is undefined.
Table 4. Function Commands
Note: EEPROM block 2 is not supported on special order devices with unique IDs.
COMMAND
Recall Data
FUNCTION
Copy Data
Lock
S SAddr W A MAddr A Sr SAddr R A Data0 A Data1 A … DataN N P
S SAddr W A MAddr=0FEh A FCmd A P
EEPROM
TARGET
BLOCK
0
1
2
0
1
2
0
1
2
VALUE
FCMD
B2h
B4h
B8h
6Ah
42h
44h
48h
63h
66h
This command copies the shadow RAM to the target EEPROM block.
Copy Data commands that target locked blocks are ignored. While the
Copy Data command is executing, the EEC bit in the EEPROM register is
set to 1, and Write Data commands with MAddr set to any address within
the target block are ignored. Read Data and Write Data commands with
MAddr set outside the target block are processed while the copy is in
progress. The Copy Data command execution time, t
and starts after the FCMD byte is acknowledged. Subsequent Copy or
Lock commands must be delayed until the EEPROM programming cycle
completes.
This command recalls the contents of the targeted EEPROM block to its
shadow RAM.
This command locks (write-protects) the targeted EEPROM block. The
LOCK bit in the EEPROM register must be set to 1 before the lock
command is executed. If the LOCK bit is 0, the lock command has no
effect. The lock command is permanent; a locked block can never be
written again. The Lock command execution time, t
and starts after the FCMD byte is acknowledged. Subsequent Copy or
Lock commands must be delayed until the EEPROM programming cycle
completes.
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DESCRIPTION
EEC
EEC
, is 2ms typical
, is 2ms typical