9ZX21501B
FIFTEEN OUTPUT DIFFERENTIAL ZBUFFER FOR PCIE GEN2/3 AND QPI
IDT®
FIFTEEN OUTPUT DIFFERENTIAL ZBUFFER FOR PCIE GEN2/3 AND QPI 11
9ZX21501B REV E 041613
General SMBus Serial Interface Information for 9ZX21501B
How to Write
• Controller (host) sends a start bit
• Controller (host) sends the write address XX
(H)
• IDT clock will acknowledge
• Controller (host) sends the beginning byte location = N
• IDT clock will acknowledge
• Controller (host) sends the byte count = X
• IDT clock will acknowledge
• Controller (host) starts sending Byte N through Byte
N+X-1
• IDT clock will acknowledge each byte one at a time
• Controller (host) sends a Stop bit
Note: XX
(H)
is defined by SMBus addess select pins.
How to Read
• Controller (host) will send a start bit
• Controller (host) sends the write address XX
(H)
• IDT clock will acknowledge
• Controller (host) sends the beginning byte location = N
• IDT clock will acknowledge
• Controller (host) will send a separate start bit
• Controller (host) sends the read address YY
(H)
• IDT clock will acknowledge
• IDT clock will send the data byte count = X
• IDT clock sends Byte N+X-1
• IDT clock sends Byte 0 through Byte X (if X
(H)
was
written to Byte 8)
• Controller (host) will need to acknowledge each byte
• Controller (host) will send a not acknowledge bit
• Controller (host) will send a stop bit
Index Block Write Operation
Controller (Host) IDT (Slave/Receiver)
TstarT bit
Slave Address
XX
(H)
WR WRite
ACK
Beginning Byte = N
ACK
Data Byte Count = X
ACK
Beginning Byte N
X Byte
ACK
O
O O
O O
O
Byte N + X - 1
ACK
PstoP bit
Index Block Read Operation
Controller (Host) IDT (Slave/Receiver)
TstarT bit
Slave Address
XX
(H)
WR WRite
ACK
Beginning Byte = N
ACK
RT Repeat starT
Slave Address
YY
(H)
RD ReaD
ACK
Data Byte Count=X
ACK
X Byte
Beginning Byte N
ACK
O
O O
O O
O
Byte N + X - 1
N Not acknowledge
PstoP bit
