ADS8422 Datasheet, PDF (22/25 Pages) Burr-Brown (TI) – 16-BIT, 4-MSPS, PSEUDO-BIPOLAR, FULLY DIFFERENTIAL INPUT, MICROPOWER SAMPLING ANALOG-TO-DIGITAL CONVERTER WITH PARALLEL INTERFACE, REFERENCE

ADS8422
www.ti.com
SLAS512B – JUNE 2006 – REVISED DECEMBER 2006
APPLICATION INFORMATION
ADS8422 TO A HIGH PERFORMANCE DSP INTERFACE
Figure 34 shows a parallel interface between the ADS8422 and a Texas instruments high performance DSP
such as the TMS320C6713 using the full 16-bit bus. The ADS8422 is mapped onto the CE2 memory space of
the TMS320C6713 DSP. The read and reset signals are generated by using a 3-to-8 decoder. A read operation
from the address 0xA000C000 generates a pulse on the RD pin of the data converter, wheras a read operation
form word address 0xA0014000 generates a pulse on the RESET/PD1 pin. The CE2 signal of the DSP acts as
CS (chip select) for the converter. As the TMS320C6713 features a 32-bit external memory interface, the BYTE
input of the converter can be tied permanently low, disabling the foldback of the data bus. The BUSY signal of
the ADS8422 is appiled to the EXT_INT6 interrupt input of the DSP, enabling the EDMA controller to react on
the falling edge of this signal and to collect the conversion result. The TOUT1 (timer out 1) pin of the
TMS320C6713 is used to source the CONVST signal of the converter.
+VAREG = 3 V
+VA = 5 V
0.1 mF
10 mF
0W
See Note A
AGND
0.1 mF
AGND
10 mF
1 mF
Ext Ref
Input
Analog
Input
CE2
TMS320C6713
DSP
EA[16:14]
ARE
TOUT1
EXT_INTG
ED[15:0]
Address
Decoder
CS
PD1/RESET
PD2
RD
ADS8422
+VBD
CONVST
BUSY
DB[15:0]
BDGND
BYTE
A. This resistor (0 Ω) can be installed to use the same 5-V supply.
Figure 34. ADS8422 Application Circuitry
I/O Supply
+VBD +2.7 V
0.1 mF
I/O Digital Ground
BDGND
+VAREG = 3 V
+VA = 5 V
0.1 mF
10 mF
0W
See Note A
AGND
0.1 mF
10 mF
AGND
0.1 mF
1 mF
AGND
ADS8422
A. This resistor (0 Ω) can be installed to use the same 5-V supply.
Figure 35. ADS8422 Using Internal Reference
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