FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
DATA Definition
Table 8. Command Byte Definitions
The DATA field in the single Data Transfer contains one or
several Command Bytes. The Command Byte identifies the
kind of operation required by the master to be performed and
has two fields, as illustrated in Figure 23:
Watchdog
Programming
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
1st Command
WD OFF
(As a 2nd
Command Byte)
(24)
1. Address field
2. Value field
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
WD 1280 ms
Wind. OFF
WD 320 ms
Wind. OFF
The address field is selected from the list in Table 7.
WD 80 ms
Wind. OFF
MSB
7
LSB
Bits
6
5
4
3
2
1
0
WD 20 ms
Wind. OFF
D6 D5 D4 D3 D2 D1 D0
D7
WD 1280 ms
Wind. ON
Address Field
Value Field
Figure 23. Command Byte
WD 320 ms
Wind. ON
Table 7. Address Field Definitions
WD 80 ms
Wind. ON
Address Field
Operation
Write
WD 20 ms
Wind. ON
001
011
Voltage Margining
Watchdog
W
W
Notes
24. The Watchdog timer is turned ON automatically after
receiving any other valid command byte changing watchdog
time.
Refer to Table 8, page 27, which summarizes the value
field definitions for the entire set of operation options.
Table 8. Command Byte Definitions
Security in Writing Commands
To improve the security level, a so-called first command is
defined to initiate each write communications. The first
command identifies the operation, which is executed by the
following Command Byte.
Operation
Address
Value
Action
Voltage Margining
0
0
0
0
1
1
0
x
0
0
0
0
0
0
0
0
1st Command
(As a 2nd
Command Byte)
Output
Nominal
A first command has the address field equal to the related
operation one, followed by a null value field (all zeros).
Table 9 summarizes first command definitions. The master
sends the first command before the Command Byte for the
intended operation.
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
x
x
x
x
x
x
0
0
0
0
0
0
0
0
0
1
1
1
0
1
1
0
0
1
1
0
1
0
1
0
+ 1.0%
+ 2.0%
+ 3.0%
+ 4.0%
+ 5.0%
+ 6.0%
Table 9. First Command Definitions
LDO Output: x=0
First Command
001 00000
Operation
Switcher Output
x=1
Voltage Margining
011 00000
Watchdog Programming
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
x
x
x
x
x
x
x
x
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
+ 7.0%
- 1.0%
- 2.0%
- 3.0%
- 4.0%
- 5.0%
- 6.0%
- 7.0%
VOLTAGE MARGINING OPERATION
After starting the communication in Writing mode, the
master sends the first command followed by the specific
Command Byte to set the required voltage margining for
either the LDO or the switcher (see Figure 24). To achieve a
simultaneous set for both LDO and switcher, two specific
commands must be issued in sequence after the first
command, one for each supply.
34701
Analog Integrated Circuit Device Data
Freescale Semiconductor
27
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