Proper Addition of Text Notes on PCBs

[tedj1]

Hi, I'm making a PCB that involves exclusively surface mount components, except for numerous through hole headers and sockets for connecting to extraneous equipment, including occasional drop-in LEDs to check for function in critical areas that I otherwise pull out and open circuit, consuming no current when not needed and ultimately not to be included in any final/perfected design. I do that in anticipation of possible problems, because I don't in all cases have the luxury of breadboarding and the circuit is somewhat experimental and any convenience tricks for checking circuit functionality simply and easily will be helpful. Fortunately, it's a slow speed circuit for which such temporary as-needed indicator LEDs will be appropriate. To assist in proper orientation of those LEDs, for example, I want to include some top side text in addition to the 'Name' fields. For example, to check that those LEDs are oriented right in their sockets, I want a note printed alongside the socket to the effect of '|PulseCheckLED', the '|' indicating the cathode side or flat side of the LED and the rest of the text indicating what function or circuit subset is being displayed by the LED at a glance. I'll do the same with, for example, a three pin connector, with text also printed on top alongside the connector with 'Red_Gnd_Green' printed to quickly indicate at a glance how the wiring should be done to a common cathode RGB LED somewhere physically nearby though not on the PCB itself, helpful to get everything right during assembly and wiring/cabling.

In Eagle's Visible Layers dialog, the tValues layer is not included in the 'Preset_Top' layer in Eagle, thus is not generally included in any printed PCB text, which I further assume is standard practice throughout the PCB manufacturing industry. For that and the following reasons, I avoid the tValues layer and I just preserve whatever text new devices contain in their 'Value' fields after import (generally through the wonderfully convenient Samacsys part downloader and Library Loader utility available through Mouser that works so well in Eagle), which makes adding new parts into circuits and dropping those parts onto the PCB a breeze. BTW, innovations like that which link parts suppliers and Eagle so seamlessly and make the job of the PCB designer so much easier are of great value and actually make circuit building much more fun. Device 'Value' fields usually contain manufacturer part number information, so those would seem to be better left alone. Those fields pop up on the PCB with part inclusion and I always just delete them. As per others' advice, I adopt the usual convention of R1, R2, C1, C2, Q1, Q1, IC1, IC2 in the 'Name' fields, which Eagle generally keeps track of automatically, that I include on the tNames layer for help in component placement.

Since tDocu is included in the default Preset_Top layer, I assume that is the place to put my additional text notes and I just add those with the Text icon and arrange as necessary.  Is that proper practice?

Please feel free to correct any of my assumptions and practices with criticisms, corrections and clarifications, as you please. Thanks so much. Eagle and PCB design have a long learning curve.

[one-of-the-robs · Accepted solution]

It's not the layer presets for the board editor that you need to worry about. If you want text on the board, it has to be on a layer that's included in the CAM job you use to generate silk screen Gerber files. Generally, that excludes tDocu, which tends to be for additional annotations on a part placement drawing.

If I'm placing extra text or drawings on my boards, I put them on the xPlace layers.

[tedj1]

Thanks.  I learned something new.  xPlace layer it will be.

Also, this site appears to be a good place to get a good idea of the look and feel of the PCB.

https://us.beta-layout.com/pcb/configuration/

It might not be equivalent to the CAM processed gerber stack, but it helps.  (the PCB Top and Bottom views)