Minimig Discussion Forum

I am using my minimig for games/demos and not WB (as I have another one for that). I am curious if someone
can tel me:

What am I missing out on when I stick with the PIC ? I know the upgrade is easier with ARM vs. PIC.

Which features in the newest core can I not enjoy when I only have PIC controller ?

(PS! I am not interested in hardfiles, nor any turbo modes are important)

However: I am eager to hear if I _have_ to upgrade to ARM to continue using the newest cores in the future, or if PIC versions of the FW will be released aswell as the ARM versions ?


Regs,
Espen

If your PIC based Minimig is just for gaming and watching demo, you will miss nothing but a bit lower floppy transfer speed.

Since there is 2 available PIC firmware for current FPGA release, you may chuse your "warrier"... firmware

PYB091224:
- 2 floppy
- no hdd support
- fat16 w/ 8.3 file name list

PGL091230:
- 4 floppy
- hdd support
- fat32 w/ long file name list (non scrolling file name like in ARM)

Both version provide full memory usage, if the pcb experienced ram upgrade.
It always will take a little time after any new FPGA release, because PIC sources need adaption and recompile to match it.

However, the ARM board will be a good choice if you like to speed-up any data transfer of sd/mmc card. Its also more easy to upgrade its firmware. I dont want to miss it!

Still its very nice to use standard PIC based Minimig with the great firmware done by Quille!

Hi,

There are also quite few OSD UI improvements like:
1.) Hires OSD display (Larger filenames displayed)
2.) Sorted directory lists when selecting files
3.) Scrolling of filename longer than available display
4.) More user friendly menus when selecting new kickstart hdfiles etc

However best features by far are:
1.) Speed... especially when using HD files.
2.) Expandability because ARM has much more RAM/FLASH space than PIC

Anyway I'm trying to keep up PIC firmware feature vise to ARM firmware but I can't make it preform better because lack of PIC ram and original pic clock.

Recently I have reached rom limits so without some really good optimizations I don't think I will be able to extend it further.
I'm going to try to fit in (but I can't promise anything):
1.) Multi block transfer for HD files, hopefully this will show a bit performance but this is not real bottleneck so I might drop this feature
2.) Menu selection of different FPGA core to allow running alternate cores
3.) Allow FPGA bootrom to request sending files from SD card to support separate rom loading for alternate cores

I'm still considering continuing PIC development on different PIC device from same family so speed would stay same but I would be able to cram more features and hopefully keep up with ARM controller development. And all you should do is to buy new PIC put in tinyboot loader init and replace current one.

Quille

I have a PIC24HJ128GP502 over here. It's the same package, remappable peripheral pins but it's not completely PIN compatible, need to move 2-3 pins. However, considering this is a through-hole device, it should be easy to make a simple vero-board adapter for it and voila, 40MHz pipelined operation, 8kB of RAM, 128kB of flash.

Oh, and 8-channel DMA for most peripherals.

Hi,

I was considering some PIC which is pin to pin compatibile with current one. Othervise ARM conroller is same thing daughter board own clock etc. Idea was to keep it simple enough for average minimig user to change pic by themselves

Something more like PIC18LF2682 or PIC18LF2685. Just more rom and bit more RAM.

Anyway I'm not sure these two would work (lack of my knowledge in electronics) pin out looks same...
But, no DMA, no higher clock so speed would stay same but It would be possible to fit more features since flash is 3x bigger.

Quille

Well, there would be a distinct difference in price between the ARM board and a PIC24H daughterboard, the latter has remappable pins etc. so very few pins need moving, namely FSEL2, DIN, 2 power connections and an extra ground. Simple enough that it could be done on strip veroboard by pretty much anyone who can wield a soldering iron. If, in addition, you move PROG_B and INIT_B and jumper off MCLR, you can have an ICSP header, since you can program a 24 fine at 3.3V VCC *and* have in-circuit debugging, which can be useful for development.

Either way, I'll have a look at the devices you are proposing and see if there are any show-stoppers but I don't think there should be really.

Hi guys.

Thanks for the detailed aswer to my original question. I will stick to my PIC then as I just need the minimig for old-skool games.

But I do like the idea ot putting a new PIC in the socket using a small adapter. I think buying a pre-made ARM board is nice, but it's no fun just to buy it and plug it into the socket It is no fun to buy the kit either, and solder the kit.

I truly like the idea of making the veroboard-interface and put a kick-ass PIC in place and rock on the hell of the original PIC with this one

Not that I need it -- but hey, with old-skool modding and things like this it is more fun to actually build and modify than to actually use the finished product
(at least, that is my opninion).


Keep up the great work on the PIC versions, dude!!!



//Espen