TM4C123GH6PM: Possibility of controlling VBUS and/or 3.3V pins via SW1 or SW2?

The 2 "power points" you identify (VBus & 3V3) are unlikely to accommodate your "switching" desire.    While it is unclear w/in your writing - a simple mechanical switch (completely separate from your LPad) may be an option for you - unless you seek MCU control to switch the EL wires On/Off.      Again - the post is unclear as to what's (really) required.

That said - the use of (very) simple, small transistors - driven by the MCU's GPIO under program control - provide great flexibility and should have (few) issues in sourcing 100mA.    It should not prove too hard to create a program which drives multiple such wire lights in sequence - yielding a compelling visual effect.     Note that if it is true that 100mA IS required - you will likely have to employ a separate power supply for the FET - EL wire combination.     The ground of that power supply must tie to the ground of your LPad.

Indeed - 100mA "IS TOO MUCH" to ask of the MCU (from any vendor).     The MCU should NOT be treated as, "Beast of Burden" but instead as a "Smart - yet 90 lb. weakling."   

We're not told of the "ideal" voltage requirements of your EL wire lights (or similar.)      Armed w/(both) your voltage & current requirements - adequate (inexpensive) transistors (likely FETs) can be suggested...

Thank you for your very informational reply!

I do need MCU control for the switches simply due to needing an interrupt handler to be able to toggle the El wire lights, similar to any blinking light. I am able to connect the switch in series with the VBUS and El wire to turn the lights on and off but no blinking effect with an interrupt.

As far as voltage goes for the El wire, it runs AC only so to power it, I have an inverter to take any DC source such as AA batteries and input 50-120V AC RMS to the El wire. Inverter itself needs at least 5V from my testing and 100ma to see any noticeable illumination.

The transistor idea is one I came across on other posts here on TI and definitely an idea worth trying out if this project is feasible in the end.
I really do appreciate your input on this!

Thank you - here's a link to a small signal FET which our firm (and many others) employ repeatedly - in satisfaction of requirements just like yours. I'd prefer you to read/review the spec - and see if you can "share in" the design effort. (you're smart enough - and questions ARE allowed) While that firm name IS new - it is the continuation of "NXP" - thus a giant. Note that our forum vendor was not listed as carrying this well known, small signal FET. (otherwise I'd have listed theirs...)

Note that the DC ratings for this device are 60V and 350mA - thus nicely "guard-banded" for your application.

assets.nexperia.com/.../2N7002P.pdf

[edit] Thinking a bit more - I believe that while (most always) an "N FET" outperforms "P FET" - the "P FET" will prove "simpler for you to drive" as the typical MCU GPIO voltages (w/out) modification should work well.    (avoiding voltage boosting, especially - as the N FET demands)

Certain of these P FETs appear in arrays (or multiples) which simplifies your use & construction.     How many "channels" of EL Wire would you like to employ?    Armed w/that data - I can direct you to a good candidate "P FET Array."     (maybe)

Hi again Cb1,

I need to run two channels of el wire, one wire for each switch (PF0 and PF4). Both channels will employ an interrupt for toggle when switch is activated while off when no switch activity.

Regards,

Michael

i wasn't clever enough (earlier) to ask you:

• your prototype skill & interest
• the urgency of this project
• relative importance of performance vs. cost 

It is always a nice gesture if we "outsiders" promote this vendor's products - and I believe, "TPS22969DNYR" (described as an "IC Load Switch") best satisfies the requirement matrix - listed above.    The device is capable of switching up to 6A - is extremely compact - costs 1.35 (USD) @ quantity 1 - and some 7K are "in stock" at (disti) Digi-Key.    There is even a pre-built Eval board - bearing this device - in stock and priced at 25 (USD).    (such an eval board "saves" you from the time/effort/cost of design & assembly of a custom pcb.)

We must note that the device is small - you may have to enlist one w/assembly skills to properly "reflow" solder this device.    Here's a photo:    (I would have posed "King Kong" next to the chip - to better illustrate size & scale - but he was (somehow) unavailable.    (something about a "film!") 

tps22969.pdf

If you can design a pcb to hold several of these devices i believe that will prove best for you.

If not - then the examples this data provides - should enable you to: "Search for, find, and construct your prototype using (similar) yet larger (possibly DIP style) devices.    The distributor earlier noted has an excellent "Search facility" which is accessed from their first, web page.

One last caution - Pin PF0 cannot be immediately used as you propose.    (it and PD7 default into another mode of operation - and must be "unlocked" to enable them to perform as GPIO Outputs.    which is what you require.)    I believe it simpler for you to (forget) about PF0 for now - and choose another pin.

Also - there is NO requirement for you to add the complications (always) introduced by "Interrupts."     You may write "normal code" which drives the 2 outputs in a recognizable sequence - and is free of interrupts.   Only later - when you've achieved proper operation - would I, "Seek the refinement of Interrupts."     Adding "difficulty" up front - is NOT famed for yielding success - too often delays & (may) damage devices...