NCP4208
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23
Table 9. I
2
C Commands for the NCP4208
Cmd
Code
R/W Default Description
#
Bytes
Comment
0x01 R/W 0x80 Operation 1 00xx xxxx – Immediate Off
01xx xxxx – Soft Off
1000 xxxx – On (slew rate set by soft−start) − Default
1001 01xx – Margin Low (Ignore Fault)
1001 10xx – Margin Low (Act on Fault)
1010 01xx – Margin High (Ignore Fault)
1010 10xx – Margin High (Act on Fault)
0x02 R/W 0x17 ON_OFF_Config 1
Configures how the controller is turned on and off.
Bit Default Comment
7:5 000 Reserved for Future Use
4 1 This bit is read only. Switching starts when
commanded by the Control Pin and the
Operation Command, as set in Bits 3:0.
3 0 0: Unit ignores OPERATION commands over
the I
2
C interface
1: Unit responds to OPERATION command,
powerup may also depend upon Control input,
as described in Bit 2
2 1 0: Unit ignores EN pin
1: Unit responds EN pin, powerup may also
depend upon the Operation Register, as
described for Bit 3
1 1 Control Pin polarity
0 = Active Low
1 = Active High
0 1 This bit is read only.
1: means that when the controller is disabled it
will either immediately turn off or soft off (as set
in the Operation Command)
0x03 W NA Clear_Faults 0 Writing any value to this command code will clear all Status Bits
immediately. The SMBus ALERT
is deasserted on this command. If the
fault is still present the fault bit shall immediately be asserted again.
0x10 R/W 0x00 Write Protect 1
The Write_Protect command is used to control writing to the I
2
C
device. There is also a lock bit in the Manufacture Specific Registers
that once set will disable writes to all commands until the power to
the NCP4208 is cycled.
Data Byte Comment
1000 0000 Disables all writes except to the Write_Protect
Command
0100 0000 Disables all writes except to the Write_Protect
and Operation Commands
0010 0000 Disables all writes except to the Write_Protect,
Operation, ON_OFF_Config and
VOUT_COMMAND Commands
0000 0000 Enables writes to all commands
0001 0000 Disables all writes except to
WRITE_PROTECT, PAGE and all
MFR−SPECIFIC Commands
0x19 R 0xB0 Capability 1
This command allows the host to get some information on the I
2
C
device.
Bit Default Comment
7 1 PEC (Packet Error Checking is supported)
6:5 01 Max supported bus speed is 400 kHz
4 1 NCP4208 has an SMBus ALERT pin and ARA
is supported
3:0 000 Reserved for future use
0x20 R 0x20 VOUT_MODE 1 The NCP4208 supports VID mode for programming the output voltage.
0x21 R/W 0x00 VOUT_COMMAND 2 Sets the output voltage using VID.
