ncp4200 ON Semiconductor, ncp4200 Datasheet - Page 20

• Manufacturer Part Number: ncp4200
• Description: Programmable Multi-phase Synchronous Buck Converter With Pmbus
• Manufacturer: ON Semiconductor

Read Word
bytes from a slave device as follows:
Block Read
byte, the slave sends a byte count followed by the stated
number of data bytes to the master device as follows:
Table 10. VR11.1 and VR11 x VID CODES for the NCP4200
In this operation, the master device receives two data
In this operation, the master device sends a command
10. The master asserts ACK on SDA.
11. The slave sends the second Data Byte (high Data
12. The masters asserts a No ACK on SDA.
13. The master asserts a stop condition on SDA and
S
1
1. The master device asserts a start condition on
2. The master sends the 7−bit slave address followed
3. The addressed slave device asserts ACK on SDA.
4. The master sends a command code.
5. The slave asserted ACK on SDA.
6. The master sends a repeated start condition on
7. The master sends the 7 bit slave address followed
8. The slave asserts ACK on SDA.
9. The slave sends the first Data Byte (low Data
1. The master device asserts a START condition on
2. The master sends the 7−bit slave address followed
3. The addressed slave device asserts ACK on SDA.
4. The master sends a REPEATED START condition
Figure 19. Word Read from a Command Code
OUTPUT
1.60000
1.59375
1.58750
1.58125
1.57500
1.56875
1.56250
ADDRESS
SDA.
by the write bit (low).
SDA.
by the read bit (high)
Byte).
Byte).
the transaction ends.
SDA.
by the write bit (low).
on SDA.
SLAVE
OFF
OFF
2
W
3
A
COMMAND
CODE
4
VID7
0
0
0
0
0
0
0
0
0
A
5
S
6
ADDRESS
SLAVE
VID6
7
0
0
0
0
0
0
0
0
0
(MSB)
DATA
R
11
A
8
12
DATA
(LSB)
A P
9
13
VID5
0
0
0
0
0
0
0
0
0
http://onsemi.com
10
A
20
VID4
0
0
0
0
0
0
0
0
0
PMBus Timeout
is no PMBus activity for 35 ms, the NCP4200 assumes that
the bus is locked and releases the bus. This prevents the
device from locking or holding the PMBus expecting data.
Some PMBus controllers cannot handle the PMBus timeout
feature, so it can be disabled.
Configuration Register 1 (0xD1)
Bit 3 SMB_TO_EN = 1; PMBus timeout enabled.
Bit 3 TODIS = 0; PMBus timeout disabled (default).
Virus Protection
critical NCP4200 register settings, the lock bit can be set.
Setting Bit 0 of the Lock/Reset sets the lock bit and locks
critical registers. In this mode, certain registers can no
longer be written to until the NCP4200 is powered down and
powered up again. For more information on which registers
are locked see the Register Map.
The NCP4200 includes a PMBus timeout feature. If there
To prevent rogue programs or viruses from accessing
10. The master asserts ACK on SDA.
12. After the last data byte the master asserts a No
13. The master asserts a STOP condition on SDA.
11. The slave sends the remainder of the data byes, the
5. The master sends the 7−bit slave address followed
6. The slave asserts ACK on SDA.
7. The slave sends the byte count N.
8. The master asserts ACK on SDA.
9. The slave sends the first data byte.
Figure 20. Block Write to a Command Coder
by the read bit (high).
master asserts an ACK on SDA after each data
byte.
ACK on SDA.
S
1
ADDRESS
VID3
SLAVE
0
0
0
0
0
0
0
0
1
2
8
A
W
BYTE 1
DATA
3
A
9
S
VID2
0
0
0
0
1
1
1
1
0
ADDRESS
SLAVE
10
4
A
...
5
R
...
6
A
VID1
BYTE N
0
0
1
1
0
0
1
1
0
BYTE COUNT
DATA
11
7
= N
12
A
13
P
VID0
0
1
0
1
0
1
0
1
0