ADS8344 and AVR mega16

Jan 10, 2005 1 Replies
F

Hi,



I am about to create connection between an ADS8344 and a ATmega16, using the SPI interface. Is there someone that can give me any tip?? Should I have separate ground planes?? And if so, which of the pins on the A/D-converter should be connected to the analog GND (AGND) and which should be connected to just GND?? And the GND-pins on the mega16, they are all digital, arn't they?? For the AVR mega16 I'll use a chrystal on about



6MHz. The A/D-converter have 8 analog signals of about 1V on the input and the maintask for the AVR is just to convert the SPI-signal to UART-signal, whick will be send further. Will the mega16 need any decoupling capacitors?? In the datasheet of the ADC, there are some pictures of the basic operation, including the decpupling capacitances and so on, but I can't find anything about the mega16.

As you can see, I am new in the area and I am geatful for any information I can get!



Ragrds Frida



Vote
Twitter Facebook LinkedIn
D

"Frida" banged on the keyboard until producing news: snipped-for-privacy@localhost.talkaboutelectronicequipm ent.com:

AGND should be its own plane, and should surround all the AGND pins and analog signals. There should be a SINGLE tie point between AGND and GND - single as if there were only a jumper connecting them. In fact, doing it that way and using a ferrite choke is not a bad way to go.

Otherwise, GND is GND; it will be the digital ground used by all the other chips.

Decoupling caps are never a bad thing in ANY digital design :-)

Decoupling caps should be _physically_ connected between your power supply and Vcc on the chips; branching the trace out to the cap is electrically "equivalent" but not functionally *identical*.

Google around to find tutorials on PWB/PCB layout & design; you'll find plenty of help.

HTH

* * * * * * * * * * * * * * * * * Dorsai - Author of Erotic Fiction http://www.asstr.org/~Dorsai * * * * * * * * * * * * * * * * * "Some mornings it just doesn't seem worth it to gnaw through the leather straps." -- Emo Philips
Vote
Twitter Facebook LinkedIn

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required