Texas Instruments ADS869 Series Manual page 44

ADS8694, ADS8698
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
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
MAN_Ch_n mode.
Sample N
CS
SCLK 1 2 14
MAN_Ch_n Command
SDI
SDO
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
during subsequent data frames. The timing diagram in
channel 1 is selected in the manual sequencing mode. For switching between MAN_Ch_n mode and
AUTO_RST mode; see the
Sample
N
CS
SCLK
SDI
MAN_Ch_1 xxxx
SDO
Sample N Data
Based on Previous
Mode Setting
(Ch 1 is selected and device continuously converts Ch 1 if NO_OP command is provided)
44 Submit Documentation Feedback
Table 6
CS can go high immediately after MAN_Ch_n
command or after reading frame data.
16 17
15 18 32 33
X
X X X
Data from Sample N
D17 D16 D3 D2
Figure 86. Enter MAN_Ch_n Scan Mode Timing Diagram
Channel Sequencing Modes
Ch 1 Ch 1
Sample Sample
0000h xxxx
Ch 1 Data
MAN_Ch_n Mode
Figure 87. Device Operation in MAN_Ch_n Mode
Product Folder Links:
Figure 86. As shown in
for a list of commands to select individual channels during
Enters MAN_Ch_n Mode on CS Rising Edge
st
1 Sample of Manual Channel N
34 1 2
X X
X X
D1 D0
Continued Operation in the Selected Mode (NO_OP)
Figure 87 shows this behavior using an example in which
section.
Ch 1
Sample
0000h xxxx MAN_Ch_3
Ch 1 Data
ADS8694 ADS8698
Figure 86, the CS signal can be
nd
2 Sample of Manual Ch. n
16 34
14 15 33
Stays in MAN_Ch_n Mode if
SDI is Low in a Data Frame
Sample 1 of Channel n
Range Select Registers
Ch 3
Sample
xxxx 0000h
Ch 1 Data
MAN_Ch_n Mode
(Transition from Ch1 to Ch 3)
Copyright © 2015, Texas Instruments Incorporated
www.ti.com
section)
xxxx
Ch 3 Data