This has been really fascinating... we all know about sectors and tracks and stuff. But before watching this series, I've had very little idea of what that REALLY means... Excellent exploration.
I'm sorry George but I've not had much time to watch your videos on the Floppy Disk subject. I can only guess that based on this video you've made fantastic progress! Congratulations on your accomplishment. I'm sure many from Ben Eater's 6502 crowd will be looking at this with anticipation of bringing a floppy interface to their builds as well.
It's so cool to see the nitty gritty details of this subject. It might make sense later to offload the realtime and error- checking stuff to an MCU, so the CPU can issue commands and read/write FIFOs only as needed, freeing up the CPU for other things.
I don't really want to add an MCU to the FDC as I quite like it being a bit dumber than that - but one day I might add DMA so that it can write the whole sector to RAM without the CPU being involved. Maybe even booting from floppy disk without any ROM in the system!
I think the next step after that would be to also put the filesystem / DOS functionality in there. And eventually you will end up with something somewhat like a Commodore disk drive.
Hey Martin, yes, I was considering using the Acorn DFS format for that. But then, I already have fat32 code that I use on SD cards, that might be easy to adapt. Pretty wasteful on a floppy disc though!
Great project and nice videos! Are you still planning on writing to disks and making videos for that? I'm sure I am not alone in wanting to see that. Keep up the good work!
Hi! Awesome work! As for the random bugged lins in the read images: You're supposed to check the CRC and retry a read if it's incorrect. Its perfectly normal for reads (and writes) to fail randomly from time to time, depending on many factors. Also, where's is the next part? :-)
Yes indeed, it probably is - but the image loading program is not checking the error codes. It is possible that adding retries there would help, and I could make it fill the line with red if it still can't load it. I should have thought of these things at the time!
Hi Brett, it's the one from this video, quite a while ago: th-cam.com/video/cFJX95zQj4w/w-d-xo.html There aren't any significant changes since then, but I have replaced some of the logic with a 16v8 PLD - especially the coordination of cpu clock, write timing, etc.
This has been really fascinating... we all know about sectors and tracks and stuff. But before watching this series, I've had very little idea of what that REALLY means... Excellent exploration.
Me neither! It's really interesting to see these things from the other side of the fence.
Very nice 6502 Homebrew Floppy Disk Controller that is loading data from a floppy disk...
I'm sorry George but I've not had much time to watch your videos on the Floppy Disk subject. I can only guess that based on this video you've made fantastic progress! Congratulations on your accomplishment. I'm sure many from Ben Eater's 6502 crowd will be looking at this with anticipation of bringing a floppy interface to their builds as well.
Thanks Jeff. It's been very interesting figuring all this out, and getting it working.
It's so cool to see the nitty gritty details of this subject. It might make sense later to offload the realtime and error- checking stuff to an MCU, so the CPU can issue commands and read/write FIFOs only as needed, freeing up the CPU for other things.
I don't really want to add an MCU to the FDC as I quite like it being a bit dumber than that - but one day I might add DMA so that it can write the whole sector to RAM without the CPU being involved. Maybe even booting from floppy disk without any ROM in the system!
I think the next step after that would be to also put the filesystem / DOS functionality in there. And eventually you will end up with something somewhat like a Commodore disk drive.
Really neat to see at this level of detail. Thanks for sharing!
The demos of loading picture data to you VGA display were really slick. You could pretty easily build a file system at this point.
Hey Martin, yes, I was considering using the Acorn DFS format for that. But then, I already have fat32 code that I use on SD cards, that might be easy to adapt. Pretty wasteful on a floppy disc though!
Top notch explanation
Very informative videos. Keep up the good work
Thanks Eddie, glad you like them!
Amazing! 😁
Great project and nice videos! Are you still planning on writing to disks and making videos for that? I'm sure I am not alone in wanting to see that. Keep up the good work!
Thanks! Yes I'm still planning to do that, but I don't know when.
Hi! Awesome work! As for the random bugged lins in the read images: You're supposed to check the CRC and retry a read if it's incorrect. Its perfectly normal for reads (and writes) to fail randomly from time to time, depending on many factors.
Also, where's is the next part? :-)
If the second image is corrupt, should not the crc fail?
Yes indeed, it probably is - but the image loading program is not checking the error codes. It is possible that adding retries there would help, and I could make it fill the line with red if it still can't load it. I should have thought of these things at the time!
What are you using for video out these days? Did you refine that VGA system?
Hi Brett, it's the one from this video, quite a while ago: th-cam.com/video/cFJX95zQj4w/w-d-xo.html
There aren't any significant changes since then, but I have replaced some of the logic with a 16v8 PLD - especially the coordination of cpu clock, write timing, etc.
@@GeorgeFoot Thanks. Lost track of it all :)