AD8403 - SDPAPI interface

Document created by lallison Employee on Apr 3, 2017
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Hi

 

I am trying to communicate to the AD8403 Evaluation board via SDP-B platform. I have received an evaluation software with the board which works fine. I would like to communicate to the board via VB.net script and hence I am using the sdpapi1.dll which comes with the software. However I am not able to the connect to the board because the sdp needs a unique ID to identify the daughter board connected to the SDP. Can anyone please help me with the ID.

 

Thank you

 

Hi,

 

The ID is 0x6065710100000013

 

Kind Regards,

David

 

Hi David

 

I have managed to start communication with the daughter board. But I am not able to write any values to the DACs.

 

Are you able to provide any support?

 

Thank you

Mustansir Kheriwala

 

Hi,

 

Unfortunately I cant help with the code but I'll try to help with the setup:

 

First, have you setup the GPIO pins of the SDP board?

Figures 11 and 13 of the UG-255 will help this explanation:

 

Since this is a multiDAC board, there are different SYNC lines.

The AD8403 uses SYNC1, set up GPIO pins 5, 6, 7 to be outputs at logic 0. This selects S0 (SYNC1) on the Mux.

 

The AD8403 also uses /SHDN and /RESET, set up GPIO1 and GPIO3 to be outputs at logic 1.

 

If you have done this already or if you still experience issues, please let me know.

 

Regards,

David

 

Hi David

 

Thank you for your support. Sorry I am very new to this type of programming.

I have setup the pins as you suggested. Also I am able to change the values for RDAC1, but I am not sure how to write to a specific resistor.

 

Thank you

Mustansir Kheriwala

 

Hi,

 

When you write to RDAC1, are you seeing a change in the wiper value when measured?

 

I'm not sure what you mean by specific resistor, do you mean another channel e.g. RDAC2

 

Regards,

David

 

Hi David

 

I am able to set values to RDAC1. At 0 and 255(FF) Wiper1 changes resistance as expected. How do I set values to RDAC2, RDAC3 and RDAC4.

 

As per the data sheet, AD8403 chip will read the 10bit data. 1st 2 bits are address and next 8 bits are wiper position. The programming interface only allows to send 8 bit data. I am not sure how to set the address to change values of RDAC2,3,4.

 

Kind Regards

Mustansir Kheriwala

 

Hi,

 

Ok, sounds like you're successfully communicating to the part.

 

As you've stated the AD8403 requires a 10-bit write, what I suspect is happening is the part is taking the eight LSB and the part is adding 0, 0 for the address.

 

To change the address, you'll need to change A1 and A0 (Bits 10 and 9). Im not familiar with the code but I believe that there is a parameter called "word size" or "word length" that needs to be changed from 8 to 10 bits.

AD8403.PNG

If you need further assistance with the SDP code, the guys at http://ez.analog.com/community/circuits_from_the_lab/sdp will be better able to help you. If you have any more questions on the AD8403, please let me know.

 

Kind Regards,

David

 

This document was generated from the following discussion: AD8403 - SDPAPI interface

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