QM range App Note, document number 260283, rev 15
Page 43 of 48
Supported PMBus™ Commands
See references [1], [2], and [3] for details of the PMBus™ command structure and transaction types.
Command Name
Command Code
Transaction Type(s)
Notes
OPERATION
01h
Read/Write Byte
ON/OFF CONFIG
02h
Read/Write Byte
CLEAR FAULTS
03h
Send Byte
CAPABILITY
19h
Read Byte
STATUS BYTE
78h
Read/Write Byte
General unit status
STATUS_FANS_1_2
81h
Read/Write Byte
Fan faults or warnings
READ
TEMPERATURE
8Dh
Read Word
LINEAR11 format
READ FANSPEED 1
90h
Read Word
LINEAR11 format
READ FANSPEED 1
91h
Read Word
LINEAR11 format
PMBus™ REVISION
98h
Read Byte
MANUFACTURER ID
99h
Read Block
ASCII string
–
“TDK_LAMBDA”
MANUFACTURER
MODEL
9Ah
Read Block
ASCII String
– “QM”
MANUFACTURE
DATE
9Dh
Read Block
Special format
SERIAL NUMBER
9Eh
Read Block
ASCII string
– 10 characters
RUNTIME
C4h
Read Block
Special format
POWER CYCLE
COUNT
C5h
Read Block
Special format
SOFTWARE VERSION
NUMBER
C6h
Read Word
Special format
More details for each command are given in the sections below.
Controlling the Module Outputs of the Unit
Modes of Operation
There are 6 distinct modes of operation:
1. Module outputs enabled when Input Power is present (factory default)
2.
Module outputs enabled when commanded to by the PMBus™ Operation Command
3.
Module outputs enabled when the PMBus™ Control Pin is HIGH
4.
Module outputs enabled when the PMBus™ Control Pin is LOW
5. Module outputs enabled when commanded to by the
PMBus™ Operation Command AND the PMBus™
Control Pin is HIGH
6.
Module outputs enabled when commanded to by the PMBus™ Operation Command AND the PMBus™
Control Pin is LOW
The active mode of operation is selected using the On/Off Configuration Command (02h) described below.
From the factory, units are programmed to default to mode (1) so that units may be used without a PMBus™
connection.
N.B. The output state of all modules fitted in a QM unit are switched together. Individual control of the separate
modules within a QM unit is not possible. If multiple QM units (maximum of 8) are connected to the bus, each
unit can be controlled independently.