EVAL-AD7265EDZ View Datasheet(PDF) - Analog Devices

Part Name

Description

MFG CO.

EVAL-AD7265EDZ

Differential/Single-Ended Input, Dual 1 MSPS, 12-Bit, 3-Channel SAR ADC

Analog Devices 

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AD7265 TO DSP563xx

The connection diagram in Figure 46 shows how the AD7265

can be connected to the ESSI (synchronous serial interface) of

the DSP563xx family of DSPs from Motorola. There are two

on-board ESSIs, and each operates in synchronous mode

(Bit SYN = 1 in CRB register) with internally generated word

length frame sync for both TX and RX (Bit FSL1 = 0 and

Bit FSL0 = 0 in CRB).

Normal operation of the ESSI is selected by making MOD = 0

in the CRB. Set the word length to 16 by setting Bit WL1 = 1

and Bit WL0 = 0 in CRA.

To implement the power-down modes on the AD7265, the

word length can be changed to 8 bits by setting Bit WL1 = 0 and

Bit WL0 = 0 in CRA. The FSP bit in the CRB should be set to 1

so the frame sync is negative. It is imperative for signal

processing applications that the frame synchronization signal

from the DSP563xx provides equidistant sampling.

AD7265

In the example shown in Figure 46, the serial clock is taken

from the ESSI0 so the SCK0 pin must be set as an output,

SCKD = 1, while the SCK1 pin is set as an input, SCKD = 0. The

frame sync signal is taken from SC02 on ESSI0, so SCD2 = 1,

while on ESSI1, SCD2 = 0; therefore, SC12 is configured as an

input. The VDRIVE pin of the AD7265 takes the same supply

voltage as that of the DSP563xx. This allows the ADC to operate

at a higher voltage than its serial interface and therefore the

DSP563xx, if necessary.

AD72651

SCLK

DOUTA

DOUTB

CS

VDRIVE

DSP563xx1

SCK0

SCK1

SRD0

SRD1

SC02

SC12

VDD

1ADDITIONAL PINS OMITTED FOR CLARITY.

Figure 46. Interfacing the AD7265 to the DSP563xx

Rev. A | Page 25 of 28

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