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Questions relating to designing PCBs
By uChip
#172873
The attached zip file contains an Eagle library for a new letter (8.5x11") frame that hopefully folks will find useful.

Why use frames? I like to use frames because 1) they show the borders and proportions of the page that will be printed which helps me optimize the schematic to make most use of the printed space, and 2) they automatically record, or encourage/remind me to record information that will help identify the drawing after it is printed out.

Why a new frame? There are already letter sized, A4 sized and legal pad sized frames available in the Sparkfun Aesthetics library and many more in the base Eagle libraries so why create a new one? None of the Eagle frames I looked at have the features I want. The Sparkfun letter sized frame has the OSHW license reference embedded in it. I love OSHW but the frame puts text in the layout view that interferes with resizing of the layout. I'd rather have that embedded in the OSHW logo than in the more generic frame. In addition I just submitted a board where there is no date or revision info on the PCB. Just an oversight on my part but annoying. Worse it is the second time I've made that mistake. I am therefore looking to automate or at least remind me so I don't do that again. Finally, I kind of like the "European Style" frame with the grid-border for helping to locate parts which is currently only available in the A4 sized frame in the Sparkfun library.

The new frame has several attributes. Like the Sparkfun frame it is derived from, the frame automatically fills in the filename, last saved date/time and the sheet number. It also has the following attributes that you can set manually by clicking on the frame with the attributes tool or by right-clicking the frame origin and selecting attributes from the popup menu.

- >CNAME this would be the company name
- >DESIGNER this would be the name of the engineer or draftsman that prepared the drawing & layout
- >CREVISION this would be the version code for this design
- >DATECODE this the date code that will be on the PCB

Each of these are arbitrary strings. You could set them to whatever you like. The frame is not just a schematic symbol. It also has a "package" definition that places the CNAME, DATECODE and CREVISION strings in the bottom layer copper on the PCB. You therefore have an "automatic" link between the drawing and the PCB. i.e. It will be harder for me to make my mistake again and leave off this information.

Example text on PCB:
REDBOX ENGINEERING
07JUL2014
v2.1

Is this the best solution? I don't know but I find it useful. I submit it as much as an example of utilizing attributes as I do as an improved frame. If it doesn't work for you, change it. If you have an improvement, share it!

Thanks for reading.
- Chip
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By shakilabanu
#172881
Thanks for sharing. I for one can use this immediately.