Datasheet

Data Sheet AD7490
Rev. D | Page 15 of 28
Figure 14 shows how a sequence of consecutive channels can be
converted on without having to program the Shadow register or
write to the part on each serial transfer. Again, to exit this mode
of operation and revert back to the normal mode of operation
of a multichannel ADC (as outlined in Figure 12), ensure that
the WRITE = 1 and SEQ = SHADOW = 0 on the next serial
transfer.
02691-013
CONTINUOUSLY CONVERTS ON THE
SELECTED SEQUENCE OF CHANNELS BUT
WILL ALLOW RANGE, CODING, AND SO ON,
TO CHANGE IN THE CONTROL REGISTER
WITHOUT INTERRUPTING THE SEQUENCE
PROVIDED, SEQ = 1, SHADOW = 0
DUMMY CONVERSIONS
DIN = ALL 1s
DIN: WRITE TO CONTROL REGISTER,
WRITE BIT = 1,
SELECT CODING, RANGE, AND POWER MODE
SELECT CHANNEL ADD3 TO ADD0 FOR
CONVERSION,
SEQ = 1 SHADOW = 1
CS
DOUT: CONVERSION RESULT FROM
CHANNEL 0
CONTINUOUSLY CONVERTS ON A
CONSECUTIVE SEQUENCE OF CHANNELS
FROM CHANNEL 0 UP TO AND INCLUDING
THE PREVIOUSLY SELECTED ADD3 TO ADD0
IN THE CONTROL REGISTER
CS
CS
WRITE BIT = 1,
SEQ = 1,
SHADOW = 0
POWER ON
WRITE
BIT = 0
WRITE BIT = 1,
SEQ = 1,
SHADOW = 0
Figure 14. SEQ Bit = 1, SHADOW Bit = 1 Flowchart