exxos's Atari, Amiga & retro forum

The v3's of the Phoenix Sparkalaphobia for the H4/5 are on their way from the pcb and assembly plant. I hadn't actually realised how small these boards are as the 3D models have been blown up on the screen.

On top of the v2:


How it will be placed on the H/5:

These arrived today. Now to assemble the top side. Looking forward to moving to this board for my development as the original STFM setup I have is not ideal for me. H4/5 is easier to dev on.

Is it me being a noob, or the smd fpga has been replaced by a ball grid array ?

sporniket wrote: 26 Oct 2020 16:35 Is it me being a noob, or the smd fpga has been replaced by a ball grid array ?

That is correct the FPGA is now BGA based (UBGA to be precise) so it can fit within the Blitter socket space. One the chips are cheaper and two it enables us to get the board down to a reasonable size.

Icky wrote: 26 Oct 2020 16:55

sporniket wrote: 26 Oct 2020 16:35 Is it me being a noob, or the smd fpga has been replaced by a ball grid array ?

That is correct the FPGA is now BGA based (UBGA to be precise) so it can fit within the Blitter socket space. One the chips are cheaper and two it enables us to get the board down to a reasonable size.

As someone who knows absolutely nothing about BGA, what techniques and equipment can be used to solder these types of chips at home? :)

I'm seriously impressed with this project!
With the blitters becoming more and more rare this is a huge deal, and maybe open up for adding some additional features (c2p perhaps?)

I've always wanted to go BGA but the chips seemed too much of an arse to solder. In the end i found i could solder an ICE40 inside a 84 pin PLCC package and pretty much do what you did here.

agranlund wrote: 27 Oct 2020 09:33 As someone who knows absolutely nothing about BGA, what techniques and equipment can be used to solder these types of chips at home? :)

It can be done at home but is not the easiest to do. Our assemblers can do this for us and have an x-ray machine so they can check there are no shorts or missing contacts underneath.

agranlund wrote: 27 Oct 2020 09:33 I'm seriously impressed with this project!
With the blitters becoming more and more rare this is a huge deal, and maybe open up for adding some additional features (c2p perhaps?)

Thats the idea is to provide an alternative as they are becoming scarce.

terriblefire wrote: 27 Oct 2020 09:57 I've always wanted to go BGA but the chips seemed too much of an arse to solder. In the end i found i could solder an ICE40 inside a 84 pin PLCC package and pretty much do what you did here.

Yeah - the 84 pin is a little bigger to play with in size, the PLCC 68 doesn't have much room. Am finding that BGA chips are becoming a lot cheaper than the SMT leaded variants.

The most craziest example I have seen for an FPGA in a PLCC-68 package is this and fits directly into the socket. However its very expensive and 3.3V. Just shows how small things are getting. https://www2.hdl.co.jp/en/plink/ap68-10.html

I wonder why they did a hole beside each pin? Some kind of stress relieve on the pcb and get some flex in each pin?

Got my board from @Icky All days ago to attempt to solder the uBGA.

I got my new solder paste printer on the go...

Considering how tiny these pads are it really is amazing that the printer can get down to this resolution :shock: I reflowed the solder as I don't feel confident in lining up the chip by hand without smudging the paste...

After some thinking I needed some way to physically hold the chip in alignment rather than endless trial and error.. So I came up with a template board...


The PLCC68 pins I can put in the template and actual PCB, then the FPGA uBGA chip will be aligned with a hole in the template board. So in theory as soon as the printer has pasted, I can use the template to manually align the chip and reflow it in one go..

With the PCB already having the solder melted, I plan to just dose it up with lots of flux and then put the chip on.. I can always press down a little bit now it is held in place with the template to make sure the IC pads are touching on the PCB properly.