AD7711ANZ Analog Devices Inc, AD7711ANZ Datasheet - Page 25

• Manufacturer Part Number: AD7711ANZ
• Description: 24 BIT SIGMA DELTA ADC IC
• Manufacturer: Analog Devices Inc

Specifications of AD7711ANZ

• Rohs Compliant: YES
• Number Of Bits: 24
• Sampling Rate (per Second): 1.03k
• Data Interface: Serial
• Number Of Converters: 1
• Power Dissipation (max): 45mW
• Voltage Supply Source: Analog and Digital, Dual ±
• Operating Temperature: -40°C ~ 80°C
• Mounting Type: Through Hole
• Package / Case: 24-DIP (0.300", 7.62mm)
• Resolution (bits): 24bit
• Sampling Rate: 19.5kSPS
• Input Channel Type: Differential, Single Ended
• Supply Voltage Range - Analogue: 5V To 10V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD7711 to 8051 Interface
Figure 17 shows an interface between the AD7711 and the 8XC51
microcontroller. The AD7711 is configured for external clocking
mode, while the 8XC51 is configured in its Mode 0 serial interface
mode. The DRDY line from the AD7711 is connected to the Port
P1.2 input of the 8XC51, so the DRDY line is polled by the
8XC51. The DRDY line can be connected to the INT1 input of
the 8XC51 if an interrupt driven system is preferred.
REV.G
Figure 16. Flowchart for Single Write Operation
to the AD7711
8XC51
Figure 17. AD7711 to 8XC51 Interface
P1.0
P1.2
P1.3
P3.0
P1.1
P3.1
WRITE DATA FROM
ACCUMULATOR TO
LOAD DATA FROM
TFS AND A0 HIGH
CONFIGURE AND
INITIALIZE C/ P
TFS AND A0 LOW
ACCUMULATOR
SERIAL BUFFER
SERIAL PORT
RFS, TFS AND
ADDRESS TO
ORDER OF
REVERSE
A0 HIGH
START
BRING
BRING
BRING
END
BITS
DV
DD
SYNC
RFS
TFS
DRDY
A0
SDATA
SCLK
MODE
3
AD7711
–25–
Table VII shows some typical 8XC51 code used for a single 24-bit
read from the output register of the AD7711. Table VIII shows
some typical code for a single write operation to the control
register of the AD7711. The 8XC51 outputs the LSB first in a
write operation, while the AD7711 expects the MSB first so the
data to be transmitted has to be rearranged before being written
to the output serial register. Similarly, the AD7711 outputs the
MSB first during a read operation that the 8XC51 expects the
LSB first. Therefore, the data that is read into the serial buffer
needs to be rearranged before the correct data-word from the
AD7711 is available in the accumulator.
WAIT:
READ:
POLL:
READ 1:
END:
FIN:
MOV SCON,#00010001B; Configure 8051 for MODE 0
MOV IE,#00010000B;
SETB 90H;
SETB 91H;
SETB 93H;
MOV R1,#003H;
MOV R0,#030H;
MOV R6,#004H;
NOP;
MOV A,P1;
ANL A,R6;
JZ READ;
SJMP WAIT;
CLR 90H;
CLR 98H;
JB 98H, READ1
SJMP POLL
MOV A,SBUF;
RLC A;
MOV B.0,C;
SETB 90H
SJMP FIN
RLC A; MOV B.1,C; RLC A; MOV B.2,C;
RLC A; MOV B.3,C; RLC A; MOV B.4,C;
RLC A; MOV B.5,C; RLC A; MOV B.6,C;
RLC A; MOV B.7,C;
MOV A,B;
MOV @R0,A;
INC R0;
DEC R1
MOV A,R1
JZ END
JMP WAIT
Table VII. 8XC51 Code for Reading from the AD7711
Disable All Interrupts
Set P1.0, Used as RFS
Set P1.1, Used as TFS
Set P1.3, Used as A0
Sets Number of Bytes to Be Read in
Read Operation
Start Address for where Bytes Will
Be Loaded
Use P1.2 as DRDY
Read Port 1
Mask Out All Bits Except DRDY
If Zero Read
Otherwise Keep Polling
Bring RFS Low
Clear Receive Flag
Tests Receive Interrupt Flag
Read Buffer
Rearrange Data
Reverse Order of Bits
Write Data to Memory
Increment Memory Location
Decrement Byte Counter
Jump if Zero
Fetch Next Byte
Bring RFS High
AD7711
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