Hello guys,

I'm total beginner in this field and I would like to ask few questions regarding usage of AD Converter.

I'm using CY8CKIT-050n kit, and the general idea is to bring some analog signal to AD Converter and calculate how precisely it converts it to digital. Analog source has to be external. Converter has to be in 20bit continuous mode.

I have tried finding it in documentation, but without success - where on the kit board can I connect external analog signal that will be used by ADC?

What else should be changed in ADC configuration to support external analog input?

In documentation AGL[6] is mentioned, but I cant find it on the board - can you please point me to it?

Thanks in advance!

You place the A/D component, double click it, and configure it. Then place an analog pin

and connect the two on the schematic. Next in workspace explorer, you double click the

source tab, and double click the .cydwr named file, and there is a tab there for pin selection,

to pick the actual pin that will be used.

When you start Creator, and start a new design, you can pick a sample A/D project that will set

this up for you.

Regards, Dana.

 Thank you! 

I've used one of predefined templates when creating project. However, being utter beginner, can you please tell me how can I measure voltages on P0_1 and P0_2? I have to connect voltmeter parallel to something, and i only have one branch on each side...analog and digital.

I'm appologize for, what are surely plain dumb questions, but i know of no better. :)

(Please see attached picture)

You will have to connect your meter between the pin and GND to measure the voltage at one pin. Where is the point of mis-understanding?

Bob

 I realized that, but I dont know which GND should I use. There are many of them on the board, in fact there are two GND_A on the 2x20 connector. It's clear that for the + side i should use P0_1 or P0_2, but which GND do I use? And how can i see if this is configured somwhere in the design.

Thanks!

Have a look into the schematic which you'll find as a .pdf on your CD.

Or download it here http://www.cypress.com/?rID=51577

Then you'll see that GND is best to find on TP1 (black)

Bob

Generally Boards with mixed analog and digital signal have at least 2

grounds, one for analog, one for digital. The two grounds ultimately

"join" each other at the board edge or at the power source, battery,

regulator, etc.. This is to remove from analog the digital switching noise

and I x R voltage drops, which contribute error to analog measurements.

Try measuring to all the grounds and compare. If you have a scope

look at the measurment points as you move your ground. More

sophisticated measurements would be to use the scope differentially

and look at ground drops. Tektronix, Agilent have lots of measurement

applications notes.

Attached some basic ap notes about signal integrity. Read at your leisure :)

Regards, Dana.

 Thank you!

 Take a look at this Application Note - Pin Selection for Analog Designs