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Electronics => Electronics => Topic started by: izua on August 29, 2008, 03:19:23 PM

Title: Help with schematic
Post by: izua on August 29, 2008, 03:19:23 PM

Hi, please check this schematic.
It's a breakout board for atmega 128.
What I really want to know is if the programming headers are correct, and if the chip in the left (FT232RL) is wired right (for a self powered device). The rightmost header (P-USB) is actually connected to a USB device connector, which has the pins, when in line as V+, GND, D+, D-. I'm not aware if the converter needs grounding if the 3.3 is not used. DS says it uses an internal oscillator.

Also, what should I do with the PEN pin on the atmega?

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Title: Re: Help with schematic
Post by: Admin on September 01, 2008, 03:40:53 PM

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I really want to know is if the programming headers are correct

yeap

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and if the chip in the left (FT232RL) is wired right (for a self powered device)

On the right? :P
I haven't used it before, but it looks ok on a quick glance . . .

Quote

Also, what should I do with the PEN pin on the atmega?

PEN is a programming enable pin for the SPI Serial Programming mode. I *think* you need to ground it but check the datasheet to make sure first.

Title: Re: Help with schematic
Post by: Trumpkin on September 01, 2008, 04:12:39 PM

don't you need to connect 3.3v OUT to GND through a 100nf capacitor?