Datasheet

© 2008 Microchip Technology Inc. DS22060B-page 53
MCP413X/415X/423X/425X
7.6 Read Data
Normal and High Voltage
The Read command is a 16-bit command. The format
of the command is shown in Figure 7-4.
The first 6-bits of the Read command determine the
address and the command. The 7th clock will output
the CMDERR bit on the SDO pin. The remaining
9-clocks the device will transmit the 9 data bits (D8:D0)
of the specified address (AD3:AD0).
Figure 7-4 shows the SDI and SDO information for a
Read command.
7.6.1 SINGLE READ
The read operation requires that the CS pin be in the
active state (V
IL
or V
IHH
). Typically, the CS pin will be in
the inactive state (V
IH
) and is driven to the active state
(V
IL
or V
IHH
). The 16-bit Read Command (Command
Byte and Data Byte) is then clocked in on the SCK and
SDI pins. The SDO pin starts driving data on the 7th bit
(CMDERR bit) and the addressed data comes out on
the 8th through 16th clocks. Figure 6-3 through
Figure 6-6 show possible waveforms for a single read.
Figure 6-5 and Figure 6-6 show the single read
waveforms when the SDI and SDO signals are
multiplexed on the same pin. For additional information
on the multiplexing of these signals, refer to
Section 6.1.3 “SDI/SDO”.
FIGURE 7-4: Read Command - SDI and SDO States.
Note: The High Voltage Read Data command is
supported for compatability with system
that also support MCP414X/416X/424X/
426X devices.
A
D
3
A
D
2
A
D
1
A
D
0
11XXXXXXXXXX
1111111D
8
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
Valid Address/Command combination
1111110000000000Attempted Memory Read of Reserved
Memory location.
COMMAND BYTE DATA BYTE
SDI
SDO
READ DATA