ADS7863
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SBAS383–JUNE 2007
SPECIAL MODE II (Not ADS7861-Compatible)
The CONVST and RD pins can still be tied together,
but do not need to be issued every 16 CLOCK
cycles. Output data are presented on both terminals,
SDOA and SDOB.
For Mode II, a special read mode is available in the
ADS7863 where both data results can be read out,
triggered by a single RD pulse. To activate this
mode, bit S4 in the SDI Register must be set to '1'
(see also the Serial Data Input section).
The special read mode is not available in Mode I or
Mode III. Figure 20 illustrates the special read mode.
16
1
16
1
16
1
16
1
16
1
1
1
CLOCK
CONVST
SDI
C[1:0] = '00' ® CHx0
C[1:0] = '11' ® CHx1
C[1:0] = '11' ® CHx1
C[1:0] = '11' ® CHx1
P[1:0] = '01' ® Features ON
P[1:0] = '01' ® S4 = '1'
P[1:0] = '11' ® No Updates
P[1:0] = '11' ® S4 Still = '1'
P[1:0] = '11' ® No Updates
P[1:0] = '11' ® S4 Still = '1'
P[1:0] = '11' ® No Updates
P[1:0] = '11' ® S4 Still = '1'
M0
M1
RD
CS
B
B
Previous 12-Bit
Data CHAx
12-Bit
A
12-Bit
12-Bit
A
12-Bit
12-Bit
SDOA
SDOB
BUSY
A
Data CHA0
Data CHB0
Data CHA1
Data CHB1
Data CHA1
High-Z
Previous 12-Bit
Data CHBx
Previous Conversion
of Both CHxx
Conversion
No Conversion,
Read Access Only
Conversion
No Conversion,
Read Access Only
Conversion
of Both CHx1
of Both CHx0
of Both CHx1
0ms
0.5ms
1.0ms
1.5ms
2.0ms
2.5ms
3.0ms
Figure 20. Special Mode II Timing Diagram (M0 = 0; M1 = 1; S4 = 1)
18
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