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MAN_Ch_1
Sample
N
SCLK
SDI
SDO
CS
xxxx
Sample N Data
Ch 1
Sample
0000h
xxxx
Ch 1 Data
Ch 1
Sample
0000h
xxxx
Ch 1 Data
Ch 1
Sample
MAN_Ch_3
xxxx
Ch 1 Data
Based on Previous
Mode Setting
Ch 3
Sample
0000h
xxxx
Ch 3 Data
MAN_Ch_n Mode
(Ch 1 is selected and device continuously converts Ch 1 if NO_OP command is provided)
MAN_Ch_n Mode
(Transition from Ch1 to Ch 3)
1
2
14
15
16
17
18
32
33
34
SCLK
CS
D3
SDO
Data from Sample N
D17
D16
D2
D1
D0
MAN_Ch_n Command
SDI
X
X
X
X
X
X
X
X
Sample N
Enters MAN_Ch_n Mode on CS Rising Edge
1
st
Sample of Manual Channel N
CS can go high immediately after MAN_Ch_n
command or after reading frame data.
1
2
14
15
16
Stays in MAN_Ch_n Mode if
SDI is Low in a Data Frame
33
34
2
nd
Sample of Manual Ch. n
Sample 1 of Channel n
SBAS686 – JULY 2015
8.4.2.6 Manual Channel n Select (MAN_Ch_n)
The devices can be programmed to convert a particular analog input channel by operating in manual channel
n
scan mode (MAN_Ch_n). This programming is done by writing a valid manual channel
n
select command
(MAN_Ch_n) in the command register, as shown in
. As shown in
, the CS signal can be
pulled high immediately after the MAN_Ch_n command or after reading the output data of the frame. However, in
order to accurately acquire and convert the input signal on the next channel, the command frame must be a
complete frame of 34 SCLK cycles. See
for a list of commands to select individual channels during
MAN_Ch_n mode.
Figure 86. Enter MAN_Ch_n Scan Mode Timing Diagram
The manual channel
n
select command (MAN_Ch_n) is executed and the devices sample the analog input on
the selected channel on the CS falling edge of the next data frame following this write operation. The input
voltage range for each channel in the MAN_Ch_n mode can be configured by setting the
in the program registers. The device continues to sample the analog input on the same channel if no other valid
command is executed and SDI is kept low (see the
Continued Operation in the Selected Mode (NO_OP)
section)
during subsequent data frames. The timing diagram in
shows this behavior using an example in which
channel 1 is selected in the manual sequencing mode. For switching between MAN_Ch_n mode and
AUTO_RST mode; see the
section.
Figure 87. Device Operation in MAN_Ch_n Mode
44
Copyright © 2015, Texas Instruments Incorporated
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