MCP413X/415X/423X/425X
7.5.1
SINGLE WRITE
7.5
Write Data
Normal and High Voltage
The write operation requires that the CS pin be in the
active state (VILor VIHH). Typically, the CS pin will be in
the inactive state (VIH) and is driven to the active state
(VIL). The 16-bit Write Command (Command Byte and
Data Byte) is then clocked in on the SCK and SDI pins.
Once all 16 bits have been received, the specified
volatile address is updated. A write will not occur if the
write command isn’t exactly 16 clocks pulses. This
protects against system issues from corrupting the
memory locations.
Note:
The High Voltage Write Data command is
supported for compatability with system
that also support MCP414X/416X/424X/
426X devices.
The Write command is a 16-bit command. The format
of the command is shown in Figure 7-2.
A Write command to a Volatile memory location
changes that location after a properly formatted Write
Command (16-clock) have been received.
Figure 6-3 and Figure 6-4 show possible waveforms
for a single write.
COMMAND BYTE
DATA BYTE
A
D
3
A
D
2
A
D
1
A
D
0
0
0
D
9
D
8
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
SDI
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
Valid Address/Command combination
Invalid Address/Command combination (1)
SDO
Note 1: If an Error Condition occurs (CMDERR = L), all following SDO bits will be low until the CMDERR
condition is cleared (the CS pin is forced to the inactive state).
FIGURE 7-2:
Write Command - SDI and SDO States.
© 2008 Microchip Technology Inc.
DS22060B-page 51
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