Datasheet

Data Sheet AD7949
Rev. D | Page 29 of 32
UPDATE (n)
CFG/SDO
UPDATE (n + 1)
CFG/SDO
ACQUISITION (n)
ACQUISITION
(n - 1)
MSB
1
2
BEGIN DATA (n – 1)
BEGIN CFG (n + 1)
CFG
MSB
CFG
MSB – 1
12
13
SEE NOTE
SEE NOTE
NOTES
1. THE LSB IS FOR CONVERSION RESULTS OR THE CONFIGURATION REGISTER CFG (n – 1) IF
13 SCK FALLING EDGES = LSB OF CONVERSION RESULTS.
27 SCK FALLING EDGES = LSB OF CONFIGURATION REGISTER.
ON THE 14TH OR 28TH SCK FALLING EDGE, SDO IS DRIVEN TO HIGH IMPEDANCE.
14/
28
CONVERSION (n)
END DATA (n – 1)
END CFG (n + 1)
CFG
LSB
X
X
> t
CONV
LSB
SCK
CNV
DIN
SDO
12
13
14/
28
CONVERSION (n – 1)
END DATA (n – 2)
END CFG (n)
CFG
LSB
X
X
t
CONV
t
DATA
t
CNVH
t
DATA
t
DIS
t
DIS
t
EN
t
DSDO
t
HSDO
t
HDIN
t
SDIN
t
CLSCK
t
EN
t
EN
t
SCK
t
SCKH
t
SCKL
t
DIS
t
DIS
t
CONV
LSB
t
ACQ
t
CYC
(QUIET
TIME)
(QUIET
TIME)
EOC
EOC
RETURN CNV HIGH
FOR NO BUSY
RETURN CNV HIGH
FOR NO BUSY
07351-040
Figure 40. Serial Interface Timing for the AD7949 Without a Busy Indicator