Datasheet

DS2482-100: Single-Channel 1-Wire Master
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FUNCTION COMMANDS
The DS2482-100 understands eight function commands, which fall into four categories: device control, I
2
C
communication, 1-Wire setup, and 1-Wire communication. The feedback path to the host is controlled by a read
pointer, which is set automatically by each function command for the host to efficiently access relevant information.
The host processor sends these commands and applicable parameters as strings of one or two bytes using the I
2
C
interface. The I
2
C protocol requires that each byte be acknowledged by the receiving party to confirm acceptance
or not be acknowledged to indicate an error condition (invalid code or parameter) or to end the communication.
Details of the I
2
C protocol including acknowledge are found in the I
2
C Interface section.
Device Reset
Command Code
F0h
Command Parameter
None
Description
Performs a global reset of device state machine logic.
Terminates any ongoing 1-Wire communication.
Typical Use
Device initialization after power-up; re-initialization (reset) as desired.
Restriction
None (can be executed at any time)
Error Response
None
Command Duration
Maximum 525ns, counted from falling SCL edge of the command code
acknowledge bit.
1-Wire Activity
Ends maximum 262.5ns after the falling SCL edge of the command code
acknowledge bit.
Read Pointer Position
Status register (for busy polling)
Status Bits Affected
RST set to 1,
1WB, PPD, SD, SBR, TSB, DIR set to 0
Configuration Bits Affected
1WS, APU, PPM, SPU set to 0
Set Read Pointer
Command Code
E1h
Command Parameter
Pointer Code
Description
Sets the Read Pointer to the specified register. Overwrites the read
pointer position of any 1-Wire communication command in progress.
Typical Use
To prepare reading the result from a 1-Wire Byte command; random read
access of registers.
Restriction
None (can be executed at any time)
Error Response
If the pointer code is not valid, the pointer code is not acknowledged and
the command is ignored.
Command Duration
None; the read pointer is updated on the rising SCL edge of the pointer
code acknowledge bit.
1-Wire Activity
Not affected
Read Pointer Position
As specified by the pointer code
Status Bits Affected
None
Configuration Bits Affected
None
Valid Pointer Codes
Register Selection Code
Status Register F0h
Read Data Register E1h
Configuration Register C3h