Getting info from a digital line

You need to read the datasheet for the A2D convertor on that board. I think it is an Analog Devices part. There will be a timing diagram that shown how to request a conversion and how to clock out the data serially. Then you will need to write a simple controller to read the data serially and convert into parallel form and perhaps store into a register. This would basically be a state machine and a shift register.

Now if you want to make a multimeter, the data in parallel form would need to be converted to a voltage level and then decimal form for display on 7-segment led perhaps. The easy way to do that would be to construct a 256 entry table in block ram that is addressed using the A2D data. The block ram is preloaded with decimal values based on calibration curves you generated on the A2D.

Thanks for a push in the right direction! The board is connected right now as a duaghter board, would this be serial, or rs232 serial? sorry for the seemingly simple questions but this is entirley new to me. As well do you now of any good sites to help me get started with somthing like this and fpga/vdl in general?

Thanks!

Im reading up on some of it now and was getting confused.. does teh ADC output a clock or do you give it a clock to use?

What does the data sheet say?

(Some of them can run either way - depends on mode bits.)

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I looked at the sheet and now i belive it wants a signal.. i think. The confusing part is when I look at the datasheet for the AD7823 and the AIO1, the seem to do some weird things. The CONVST label on the ADC changes over to ADCLK when it gets to the pinout, as well SCLK on the ADC changes to CONVST? Not sure why.... may take a few trial and errors to figure out what pins do what unfortunetly, or mabye Im reading it wrong...

Weizbox, They seem to number the board connectors in a funny way. On their connectors, pin 1 of the male does not connect to their pin 1 of the female.

Get the pinouts and schematics for both boards so you can tell what is really happening.

Cheers, Jim

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Expert VHDL Training for Hardware Design and Verification ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > I looked at the sheet and now i belive it wants a signal.. i think. The confusing part is when I look at the datasheet for the AD7823 and the AIO1, the seem to do some weird things. The CONVST label on the ADC changes over to ADCLK when it gets to the pinout, as well SCLK on the ADC changes to CONVST? Not sure why.... may take a few trial and errors to figure out what pins do what unfortunetly, or mabye Im reading it wrong...

a clock or do you give it a clock to use?

The clock is an input into the ADC. See page 9 of the Analog Devices data sheet. And to your earlier question to the type of serial... it is a synchronous serial protocol which means a separate clock. You often seen it called by the name SPI, Microwire, etc some of which are trademarked names from various companies but all do the same.

As for a website to get you started, Xilinx has an application note of SPI protocol. I also like the website fpga4fun.com which is informative for learning but the code examples are not very complete. They do have a simple serial interface example though.

confusing part is when I look at the datasheet for the AD7823 and the AIO1, the seem to do some weird things. The CONVST label on the ADC changes over to ADCLK when it gets to the pinout, as well SCLK on the ADC changes to CONVST? Not sure why.... may take a few trial and errors to figure out what pins do what unfortunetly, or mabye Im reading it wrong...

You may want to trace the pins with a multimeter. I had another Digilint board before and while they are affordable, the documentation is sometimes full of errors.