System Management Bus (SMBus) Specification, version 2.

System Management Bus (SMBus) Specification Version 2.0
NOTES:
1. A slave device must respond to this command even if its AR flag is SET.
2. The slave device only ACKs the PEC byte if it matches the value calculated on data it received, if not
it must NACK the PEC byte AND ignore the “Assign Address” command. This behavior allows the
host to determine that the slave device successfully accepted the address without any further bus
activity.
This command utilizes the standard SMBus Block Write Protocol with PEC as illustrated below.
1 7 1 1 8 1 8 1
S Slave Address Wr A Command A Byte Count A • • •
1100 001 0 0 0000 0100 0 0001 0001 0
8 1 8 1 8 1 8 1
Data1 A Data2 A Data3 A Data4 A • • •
UDID byte 15 (MSB) 0 UDID byte 14 0 UDID byte 13 0 UDID byte 12 0
8 1 8 1 8 1 8 1
Data5 A Data6 A Data7 A Data8 A • • •
UDID byte 11 0 UDID byte 10 0 UDID byte 9 0 UDID byte 8 0
8 1 8 1 8 1
Data9 A Data10 A Data11 A • • •
UDID byte 7 0 UDID byte 6 0 UDID byte 5 0
8 1 8 1 8 1 8 1
Data12 A Data13 A Data14 A Data15 A • • •
UDID byte 4 0 UDID byte 3 0 UDID byte 2 0 UDID byte 1 0
8 1 8 1 8 1 1
Data16 A Data17 A PEC A P
UDID byte 0 (LSB) 0 Assigned Address 0 0
5.6.3.6. Get UDID (directed)
Action: if (AV=1) then ACK/PROCESS; else NACK/REJECT.
AR Flag: NO CHANGE
AV Flag: NO CHANGE
This command requests a specific ARP-capable device to return its Unique Identifier. If the ARP Master
detects that any of the first three bytes have not been acknowledged then it can assume that no ARPcapable
device is present at the targeted slave address.
This command utilizes the standard SMBus Block Read Protocol with PEC as illustrated below.
1 7 1 1 8 1 1
S Slave Address Wr A Command A S • • •
1100 001 0 0 Targeted slave address | 1 0
7 1 1 8 1
Slave Address Rd A Byte Count A • • •
1100 001 1 0 0001 0001 0
8 1 8 1 8 1 8 1
Data1 A Data2 A Data3 A Data4 A • • •
UDID byte 15
(MSB)
0 UDID byte
14
0 UDID byte
13
0 UDID byte
12
0
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