On 10/17/2021 at 8:10 AM, Mtemal said:
I think the ICE40HX8K-CB132 is probably a good candidate that will have enough room for a full X-16 FPGA. I dunno if It’s going to require an external RAM chip to handle the X16 banking.
From the number of logic elements, it's about comparable roughly to an 80's cpu afaik, but it runs at a whopping GHz. It is difficult to solder at home onto a board which is difficult to make at home. The price however, WOW that's cheap as chips ! With prices like that I would think to look at FPGAs for other projects...
You need RAM. nothing that size can do decent video.
On 10/19/2021 at 3:59 AM, Wavicle said:
The iCE40HX8K-CB132 is a tough sell for a couple of reasons:
It's a BGA package which is a bit more fiddly for non-machine placed parts and cannot be soldered without a reflow oven.
It requires 4 PCB layers with 3.35 mil traces to access all IOs.
It lacks the 1Mb SRAM in the iCE40UP line (this is why the X8 has 64K main memory + 64K VRAM, it's using the SRAM for both)
With only 128Kb of block RAM, it would require external SRAM no matter what
yes yes huh and yes. I agree with this.
On 10/19/2021 at 6:27 AM, BruceMcF said:
If you have an "X8" on an FPGA capable of accessing a separate 1MB of RAM ... why not just make it fully compatible with the X16p and have the originally described X16e [...]After all, by that point you've pushed the price point into the $50-$100 range, so you've given up the price point that made the X8 intriguing in the first place.
I personally think that having an
onboard bus for ram is a good option, because once you have the hardware available to access one Sram or Rom in DIP,
that's the end of memory entirely, you no longer need to budget for larger memory so long as there is the Address and data bus exposed so that people can add their own. The project that shall not be named takes such an approach, because people will measure by the base model with un-expanded memory knowing full well that adding memory is a job a cat can do. (so long as a dog makes a tutorial video).
PLUS there is the added benefit that you can try before you buy, or at least not get in as deeply as purchasing a fully expanded version.
On 10/19/2021 at 3:07 PM, Mtemal said:
@EMwhite I’m not sure if imaginary is the right term. The prototypes exist. The PCB and FPGA files that are available should allow someone to build their own X8 if they have the parts in the BOM. I would be surprised if there isn’t someone running the “X8” on another FPGA solution considering that the Verilog files are in the FPGA folder.
It's the investment barrier. You have to invest in learning all about FPGA and verilog and dip your toes in the YIKES! and then learn the actual programming to write your software, so is a scary, although perfectly do-able, option.
Plus, once you have made the investment you're giddy with new knowledge and spaced out with imagination thinking of all the possibilities of what you can do with that new found knowledge and exploring beyond the X(men) projects.
On 10/19/2021 at 3:12 PM, Mtemal said:
@Wavicle I was hoping for a clever way to use a BGA package without having to increase the complexity of the PCB layer.
there are some clever solutions, but many people won't try them at home, they'd figure it too fiddly.
