I’m struggling to find something suitiable from the eaglePCB library. I’m thinking I could find another 32-pin TQFP 0.8mm Pitch Package and then edit the pinouts to match the TUSB2046?
Is this my best course of actions? And can anyone point me in the direction of a compatible footprint from the eagle library?
I’m attempting to create a custom part at the moment with Eagle but i’m struggling slightly
I have created the part, labeled all the pins but I’m stuck at sizing. I can’t work out the correct values from the datasheet for the Pad Width and Pad Height
Find the QFP 0.8 mm patterns in the library, you should find one that matches the one you are using. It’s probably something like the QFP80P900X900X145-32N. If you can’t find it, you will have to input your own data. It doesn’t create the part for you, of course. There is a PCB Libraries footprint library for the Pulsonix software I use, which makes things easy, as I just have to add it to my libraries folder. I don’t know if there is one for Eagle.
I’m trying a slightly different approach at the moment, Within Eagle i have found the Atmel Mega8-AI TQFP32-08 part which seems to match what I have. That takes care of the sizing…
Now how do I edit this parts labels to match the pinout to my datasheet?
I suggest you google around for an eagle library editor tutorial, there are several. Everything you want to do is there. It will be a lot faster than serially asking about each step.
by the way, the trick to laying out footprints in eagle is to set your grid at the interpad width (.8 mm in this case), define your pad size at what ever the datasheet says and just place the pads where you want.
The eagle lib editor is actually pretty good though they didn’t make it overly obvious to find what you need. After going through the tutorial and doing a couple of parts, I can now bang out a part very quickly - typically 10-15 minutes.
Right, i’ve created two out of the three parts I need to get going with this project. I’ve dropped the two completed parts into an eagle schematic and joined some pins to test things out.
Something I have noticed is that some pins have a green circle at the end of them and others don’t.
that dot indicates a junction. You probably doubled back on your wire. just delete the wire there and redo it. Or you could leave it that way - shouldn;t hurt anything.
By the way, I would not worry about making a schematic symbol exactly match the pinout of the chip. Instead, I group logically related pins together. gnd at the bottom, +V at the top and so on. This makes it easier to draw a clear schematic. Especially with larger chips.
Thanks for that, I can see how things could get complicated on a schematic for a large amount of pins
I’m struggling with sizing my new part. I think this is being caused by the grid size not being set correctly. How do I determine the correct grid size for a part? Is it the pitch?
if you mean grid for the schematic, keep it on .1". If you change that, you have trouble hooking it up in the schematic editor (which presumes .1" grid).
For actual footprint, you can choose any grid. One problem that arises is that various parts were defined on different grids so a nice looking layout gets tricky. Especially if you are routing to an off-grid pad. The trick is to start from the off-grid pad.
well, you are using it in a device - It doesn’t like that. go into the editor, edit the device that uses it and delete the symbol. Modify the symbol, open the device, add the symbol back and hook it up to the package pins again.
Right, i’m at the stage now where I have all three parts I needed to build done. I have printed their footprints onto paper and layed my components on top and they match up size wise.
In my inexperience of creating parts I have done each part in it own library. I would ideally like them all to be in one library for ease of use and access.
I can’t work out in eagle where I can do this, anyone?
I know this post is over a year old, but I just encountered the same problem as you and have found a workaround.
It requires deleting the deleting the device from the library editor (which could be a hassle as you will need to recreate it and specify all the pin connections - although if you are adding a completely new package you have to do this anyway)
to do so:
Library>Remove
“devicename.dev”
(where devicename is the device that is using the symbol you are trying to modify).
