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My First PCB - USB Midi Controller - any feedback?


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Hi all, I've put together a design for a MSP430 Midi controller running over USB. I really wanted to learn how to make a PCB so this is my first design (and also first time doing the schematic for the MSP). 

Hoping to get some feedback before I send it to be made. I used a rule set template for seeed studio (which has no errors now) and have been referencing some of TI's designs but I imagine I've missed a few things. Any comments or constructive criticism is much appreciated =) 

 

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Thank you heaps for the comments!

 

The pinout convention for a 3 pin SBW header is TST, RST, GND. Pretty minor, though, so if you already settled on the other way, it's OK. Or add another GND hole on the other side of the header so you can choose which side to put the ground when you solder in the header.

 

Not settled, just how I put it so will change - ty!

 

A small capacitor to GND on RST/TDIO is also recommended.

 

One of my boards occasionally reset when nearby equipment was switched on or off. This was fixed with a 100pF capacitor. I think TI recommends 1nF.

 

That's interesting you ran into some issues with it - I was looking at a few example schematics released by TI (dev boards, etc) and a few had caps in there but said "DNP" which I took as "Do Not Populate" so didn't include. The one with the reset button includes a 1nF cap and I also found some TI documentation that says it needs to be less than 2.2 nF (http://www.ti.com/lit/ug/slau278v/slau278v.pdf).%C2'>

 

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USB powered devices can sometimes have very noisy power rails depending n the enviroment. and 47k isn't the strongest pullup, so a bit of extra capacitance sometimes helps to ensure you don't get a noisy reset line.

 

I noticed with my most recent MSP430F55xx board that it would enter BSL mode when unplugged and plugged back in without waiting a second or two. I tracked it down to my design not featuring a pulldown on the PUR pin. So if you're still in design phase, might be worth adding this 1M ohm pull down.

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