Datasheet

Data Sheet ADM1075
Rev. B | Page 29 of 52
SMBus MESSAGE FORMATS
Figure 55 to Figure 63 show all the SMBus protocols supported
by the ADM1075, along with the PEC variant. In these figures,
unshaded cells indicate that the bus host is actively driving the
bus; shaded cells indicate that the ADM1075 is driving the bus.
Figure 55 to Figure 63 use the following abbreviations:
S = start condition
Sr = repeated start condition
P = stop condition
R = read bit
W
= write bit
A = acknowledge bit (0)
A
= acknowledge bit (1)
“A” represents the ACK (acknowledge) bit. The ACK bit is typi-
cally active low (Logic 0) if the transmitted byte is successfully
received by a device. However, when the receiving device is the
bus master, the acknowledge bit for the last byte read is a Logic 1,
indicated by
A
.
S P
AAWSLAVE ADDRESS DATA BYTE
S PA
AWSLAVE ADDRESS
DAT
A
BYTE PEC A
MASTER T
O SLA
VE
SLAVE TO MASTER
09312-050
Figure 55. Send Byte and Send Byte with PEC
S PAARSLAVE ADDRESS DATA BYTE
S PAARSLAVE ADDRESS DATA BYTE PEC
MASTER TO SLAVE
SLAVE TO MASTER
A
09312-051
Figure 56. Receive Byte and Receive Byte with PEC
S AAWSLAVE ADDRESS COMMAND CODE DATA BYTE
PA
S AAWSLAVE ADDRESS COMMAND CODE DATA BYTE
PA PEC A
MASTER TO SLAVE
SLAVE TO MASTER
09312-052
Figure 57. Write Byte and Write Byte with PEC
A
SLAVE ADDRESS
R
DATA BYTE
Sr
A
A
S
A
AWSLAVE ADDRESS COMMAND CODE
PA
PEC
S AAWSLAVE ADDRESS COMMAND CODE SLAVE ADDRESS
PR DATA BYTE
Sr
A
MASTER TO SLAVE
SLAVE TO MASTER
09312-053
Figure 58. Read Byte and Read Byte with PEC
P
S AA
WSLAVE ADDRESS COMMAND CODE DATA BYTE LOW
A A
S AAWSLAVE ADDRESS COMMAND CODE DATA BYTE LOW
A D
ATA BYTE HIGH
DAT
A BYTE HIGH
A
PA
PEC
MASTER TO SLAVE
SLAVE T
O MASTER
09312-054
Figure 59. Write Word and Write Word with PEC
SrA SLAVE ADDRESS
AR
S AWSLAVE ADDRESS COMMAND CODE
A
DATA BYTE LOW
PA
A
A
DATA BYTE HIGH
SrA SLAVE ADDRESS
AR
S AWSLAVE ADDRESS COMMAND CODE
A
DATA BYTE LOW
DATA BYTE HIGH
P
PEC
MASTER TO SLAVE
SLAVE TO MASTER
09312-055
Figure 60. Read Word and Read Word with PEC