Connecting Beagle board to DSP with ADCs

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1

Hi,

Can we connect the Beagleboard with DSP (or anyother controller) to
acquire data using ADCs and display on the monitor?

Thanks

2

Hi,

Can we connect the Beagleboard with DSP (or anyother controller) to
acquire data using ADCs and display on the monitor?

Yes.

3

Thanks Jason,

I am looking to connect TI DSK 6713 or 6416 with Beagle Board -xM to
collect data (from ADCs connected to DSKs) and then display on screen/
monitor using Beagle Board. Then the information (user entered) will
be sent from Beagle Board to DSKs which are connected to DACs.

Any issues in implementing such a system? Mainly, communicating with
DSK and display data on screen.

Thanks again for all the guidance.

Basu

4

Hello Basu,
I know that I am not answering your question but wouldn't it be better
to connect it direct to your Beagle Board using the expansion header?
You would have the option to transfer the data using SPI and GPIOs,
for example.
I have connected an ADC with serial output using SPI and another with
parallel output using GPIOs to my Beagle Board C4 and it works
perfect. Using -xM, the performance would probably be even better...
Best wishes,
Frederico

5

Hello Frederico,

Thanks for the information. I will look at that option. I am worried
that while the beagle board is busy displaying data on a monitor/
screen, I might miss some data on ADCs. I am still learning about
this.

Can I get some details on the speed and the ADC cards, please.

Thanks
Basu

6

Don't worry Basu. Everything is easy, after we learn it!

Of course, it is possible that you could miss some data from your
converter, it depends also on the speed you need to acquire the data.

I have been using a TLC3541 from TI with SPI output. It has a
resolution of 14 bits and speed of 200KSPS. That is no problem at all,
considering that the McSPI from Beagle Board works up to 48MHz. I have
been using McSPI4 the acquire this data.

I bought a whole evaluation board for the second ADC. That is the
THS1215EVM, also from TI. The ADC works in a 15MHz speed with 12 bits
resolution. In this case, I have been using GPIO5 from the OMAP 3530.
That way, I can obtain all the data in only one register. The data is
transfered using DMA which could also be a solution for your case. So,
the processor could be used for some other stuff other than data
transfer.

Best wishes,
Frederico

7

Hello Frederico,

I am looking for a similar ADC (200 ksps / 100 ksps, 14-16 bits) but
with at least 2 channels. Since its a prototype project I am looking
at available EVMs. Like I said I before, I need to send some voltages
to DACs with 4-5 channels.

The beagle board needs to do some data processing and display it on
the screen/monitor, not the raw data but some calculated values only,
may be plot a graph or something.

I have ordered the Beagle Board -xM (excited...), still need to find
the right EVM(s). Any suggestions with the EVMs will be helpful.

Thanks
Basu

8

Hello Basu,
I am sure there are several evaluation boards that would solve your
problem.
I did a quick search for ADCs and it seems that the TLC3544 could be a
good option:

TLC3544EVM (http://focus.ti.com/docs/toolsw/folders/print/
tlc3544evm.html)
14 bit resolution, 200kSPS, 4 channels, SPI output, US$49

This was actually an ADC that I was interested to work but due to the
simplicity and ended up choosing the TLC3541.
If I see something regarding the DAC, I will post here.
Regards,
Frederico

9

Basu,
you did not mention the information for you DACs, except for the
number of channels. Then, there are infinite possibilities...
Regarding the screen, you can connect your Beagle Board to a monitor
via HDMI connector.
I do not know what you have to calculate but I think it wouldn't be a
problem to acquire the data with 200/100 kSPS using McSPI, treat it
and plot it in the monitor.
Regards,
Frederico

10

Frederico,

I haven't figured out the details for the DAC yet. I am hoping that
anywhere from 12-16 bits should be good. The settling time is a non-
issue. It does not need to be fast. Again, having 4-5 channels is
important for the application.

If I understand it right, the -xM should be able to support a ADC EVM,
a DAC EVM and display/monitor. As long as I do not do any processing
that would loose the samples, I am good. The processing is not much,
its mostly if and else statements and storing the short data (if need
be).

Are there any softwares that allow you to write your own 'plot' codes?
For Eg, if I wanted to display data on screen similar to a MATLAB plot
(a basic one).

Thanks for ADC EVM suggestion, that looks like a perfect one for my
application.

My -xM should be here some time this week or early next week. I think
its time to order some EVMs.

Thanks again for all the help.

Regards,
Basu

11

Basu,

I am currently working with BeagleBoard version C4. I was taking a
look in the datasheet and I saw that the expansion header (Table 22)
for the -xM seems to be pretty much the same.

For the TLC3544EVM, you could easily use McSPI3 which has CS0 and CS1
to acquire the data from both channels but not at the same time.

For the DAC, you could use a port expander (PCA9555, for example) to
connect all the 4 channels to the I2C2 which is also available in the
expansion header.
If should decide about a settling time range, otherwise, it would be
hard to search for one. There would be too many options.

The monitor is no problem at all, you need just to connect to the
Board using a DVI-D cable (Figure 58 of manual) and it works right
away.

You can install whatever software you want, there are SD cards with
8GB or more and you are gonna have Linux on it. I use particularly use
levmar (http://www.ics.forth.gr/~lourakis/levmar/) to fit my data.

Regards,
Frederico

12

Frederico,

I received my -xM today. Waiting for power and other cables from
special computing.

Best Regards,
Basu