AD7851_15 Datasheet, PDF (30/36 Pages) Analog Devices – 14-Bit 333 kSPS Serial A/D Converter

AD7851
Interface Mode 1 Configuration
Figure 42 shows the flowchart for configuring the part in Inter-
face Mode 1. This mode of operation can only be enabled by
writing to the control register and setting the 2/3 MODE bit.
Reading and writing cannot take place simultaneously in this
mode as the DIN pin is used for both reading and writing.
START
POWER ON, APPLY CLKIN SIGNAL,
WAIT FOR AUTOMATIC CALIBRATION
Interface Modes 4 and 5 Configuration
Figure 43 shows the flowchart for configuring the AD7851 in
Interface Modes 4 and 5, the self-clocking modes. In this case, it
is not recommended to use the software conversion start option.
The read and write operations always occur simultaneously and
during conversion.
START
POWER ON, APPLY CLKIN SIGNAL,
WAIT FOR AUTOMATIC CALIBRATION
SERIAL
INTERFACE
MODE
?
1
YES
APPLY SYNC (IF REQUIRED),
SCLK, WRITE TO CONTROL REGISTER
SETTING THE 2-WIRE MODE
AND CONVST BIT TO 1
INITIATE
CONVERSION
IN
SOFTWARE
?
NO
APPLY SYNC (IF REQUIRED),
SCLK, WRITE TO CONTROL REGISTER
SETTING THE 2-WIRE MODE
PULSE CONVST PIN
SERIAL
INTERFACE
MODE
?
4, 5
PULSE CONVST PIN
SYNC AUTOMATICALLY GOES
LOW AFTER CONVST RISING EDGE
SCLK AUTOMATICALLY ACTIVE, READ CURRENT
CONVERSION RESULT ON DOUT PIN, WRITE
TO CONTROL REGISTER ON DIN PIN
Figure 43. Flowchart for Setting Up, Reading, and Writing
in Interface Modes 4 and 5
WAIT APPROXIMATLY 200ns
AFTER CONVST RISING EDGE
OR AFTER END OF CONTROL
REGISTER WRITE
YES
READ
DATA
DURING
CONVERSION
?
NO
WAIT FOR BUSY SIGNAL TO GO
LOW OR WAIT FOR BUSY BIT = 0
APPLY SYNC (IF REQUIRED),
SCLK, READ PREVIOUS CONVERSION
RESULT ON DIN PIN
APPLY SYNC (IF REQUIRED), SCLK, READ
CURRENT CONVERSION RESULT ON DIN PIN
Figure 42. Flowchart for Setting Up, Reading, and Writing
in Interface Mode 1
–30–
REV. B