Re: News : ARM Trying to Buy AmperComputing

On 1/23/25 8:57 PM, rbowman wrote:

On Thu, 23 Jan 2025 21:59:58 +0100, D wrote:
 

I've seen some tutorials utilizing the GPIO pins. I imagine that that is
where it would come in handy to avoid a birds nest of cables and crappy
soldering.

 I use solderless breadboards and Dupont wires when playing around. It's
quick and dirty, emphasis on the dirty part. The preformed jumpers are
neater but they're a bit of a PITA. I've seen videos of people pressing
them in with no problems but that ain't me.
 I haven't done a PCB in decades and never was very good at it but that was
before software to help with the routing. There's still a lot of overhead
for a DIY project.
 https://www.instructables.com/DIY-PCB-using-Liquid-Photoresist/

   I used to make two masks on transparency film using
   a laser printer. The masks are mirror images. You
   put the two toner layers smack together. This tends
   to fill all the little gaps. OK for 3mm spacing apps.
   Might be too fuzzy for modern submini chips.
   SMD is now sometimes the only way to get chips - and
   that means careful 'oven' work. Super-pain. Basically
   PCB development is moving out of the realm of human
   makers, everything's too tiny.

That's the basic procedure I followed. For one-offs I used presensitized
PCBs rather than spreading it on myself. For volume I'd make a silkscreen
but then you're into a whole other art form. The artwork was tape and
transfer symbols on mylar.
 Then you move on to etching. I used ferric chloride which is fairly nasty
stuff and tends to dye everything in sight yellow. Another choice was
sodium persulfate. I never used HCL and hydrogen peroxide. That seems to
have its fans.
 Then if you finally wind up with a flawless PCB the fun begins, drilling a
crap load of holes. A Dremel drill press helps. Depending on the board
material, buy a lot of bits.

   Still have my Dremel press - and boxes of the little drills.
   Patience, patience - and a steady hand.

All that makes the online services look extremely attractive.

   THESE days YES ! However back in the day most fabricators
   wanted 1000 units minimum .....
   Copper MILLING also works, grind away the unneeded copper
   on the PCB. Gotta HAVE one of those mills, of course. Not
   worth it unless you do a LOT of protos.