AD7851 Analog Devices, AD7851 Datasheet - Page 30

• Manufacturer Part Number: AD7851
• Description: 14-Bit, 333 kSPS, Serial Sampling A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7851

• Resolution (bits): 14bit
• # Chan: 1
• Sample Rate: 333kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (Vref) p-p,Uni (Vref)
• Adc Architecture: SAR
• Pkg Type: DIP,SOIC,SOP

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.
Figure 42. Flowchart for Setting Up, Reading, and Writing
in Interface Mode 1
SCLK, READ PREVIOUS CONVERSION
SCLK, WRITE TO CONTROL REGISTER
AFTER CONVST RISING EDGE
APPLY SYNC (IF REQUIRED),
OR AFTER END OF CONTROL
WAIT APPROXIMATLY 200ns
APPLY SYNC (IF REQUIRED),
SETTING THE 2-WIRE MODE
RESULT ON DIN PIN
AND CONVST BIT TO 1
REGISTER WRITE
CURRENT CONVERSION RESULT ON DIN PIN
APPLY SYNC (IF REQUIRED), SCLK, READ
SCLK, WRITE TO CONTROL REGISTER
WAIT FOR AUTOMATIC CALIBRATION
POWER ON, APPLY CLKIN SIGNAL,
YES
YES
LOW OR WAIT FOR BUSY BIT = 0
WAIT FOR BUSY SIGNAL TO GO
APPLY SYNC (IF REQUIRED),
SETTING THE 2-WIRE MODE
PULSE CONVST PIN
CONVERSION
CONVERSION
INTERFACE
SOFTWARE
INITIATE
SERIAL
DURING
START
MODE
READ
DATA
IN
?
?
?
1
NO
NO
–30–
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.
Figure 43. Flowchart for Setting Up, Reading, and Writing
in Interface Modes 4 and 5
SCLK AUTOMATICALLY ACTIVE, READ CURRENT
CONVERSION RESULT ON DOUT PIN, WRITE
TO CONTROL REGISTER ON DIN PIN
WAIT FOR AUTOMATIC CALIBRATION
LOW AFTER CONVST RISING EDGE
POWER ON, APPLY CLKIN SIGNAL,
SYNC AUTOMATICALLY GOES
PULSE CONVST PIN
INTERFACE
START
SERIAL
MODE
?
4, 5
REV. B