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About willyvmm

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    jmp $e477
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    Atari Hardware

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  1. HI again. Finally i got a fully working display, so i can show You that is really working Enjoy.
  2. Compiled diagnostic software has been attached to the blog post as well as link to source code repository. If your screen is blank, and is a mcufriend type, likely is just broken. You may use serial console (arduino serial console) to get some debug output. https://retrohax.net/atari-800-xl-refurb-sdrive-max/ w.
  3. @E474 it depend on Your difficulty definition. Compared to blinking LED id Rocket science. Compared to Apollo guidance computers od easy. Yo have to know how to read datasheet, how the software is working, how the hardware isvworking, and what to expect. Then is easy. I have no idea how mamy LCD types are sharing same layout and can be used with Arduino. @mamejay if Your LCD is working with original firmware, then it is not ili9325. The ili9325 seems to be an early version of lcd controller family, and is not compatible with newer chips. (Also more difficult to program). I have dissected some of the mcufriend lcd's, and there is possibile to mount at least 5 different LCD on PCB that are almost identical. The Only way to identify your lcd chip is to run a diagnostic software. Another problem is quality. 2 of 4 was broken when arrived. Only white screen and problem with reading id. One of them has identified itself as Renesans R61xxx (afair). So... It's lottery.
  4. HI. Some time go my friend (Drygol/Lamers) has bought a 2.8" display ... but received a 2.4" mcufriend based on ILI9325 chip. As the firmware do not support this display, I have done "driver" that support this lcd controller. Link with compiled firmware and link to source code that support this LCD is available here: https://retrohax.net/atari-800-xl-refurb-sdrive-max/ Pull request is pending, and hopefully will be merged with official firmware soon. Best Willy
  5. Hi. Thanks. Again, great job. I just started to do the same, ... but i will only complete the data. I did analyzed only MFM mode, so the following covers only ED and DD. Following FDC279x datasheet, all gaps ($4E bytes) , except one, between IDAM and DAM, can be shortened to be as short as 2 bytes. But, it is not recommended because of PLL synchronization. And the only critical structure is sector layout. All firmwares, are creating identical sector layout (using different software). IndexDatamark is optional, and is not required. SyncMarks, are special bytes, wroten with missing clock bit - its FDC special feature, "commands" F5 and F6. F5 "command" write A1 byte with missing clock bit. (pre DAM sync mark) F5 "command" write C2 byte with missing clock bit. (pre IndexMark sync mark) F7 "command" write 2 bytes CRC, calculated by Hardware In every case sector layout is identical, and is achieved by using different software tricks. MFM sector layout: 12 x $00 3 x PRE DAM sync (F5 "command") 1 x $FE (IDAM) 1 x Track number 1 x Side number 1 x Sector number 1 x Sector Length ($00 = 128, $01 = 256, $02 = 512, $03 = 1024) 2 x CRC (F7 "command") 22 x $4E (GAP - may not be shorter) 12 x $00 3 x PRE DAM sync (F5 "command") 1 x $FB (DAM) xx x DATA (128 or 256 bytes of data, it could be also 512 or 1024) 2 x CRC (F7 "command") 24 x $4E (PostData Gap) (this varries, and is sometime located in leadin area, usually 24 bytes.) All firmwares are using long track LEAD-IN, that is overlapped by last bytes/sector leadout, it is (i guess) to erase any remaining data on track. Thats, not true for xf551 - because of using Index hole. IndexMark, and PreIndexMark Sync are optional, and not required by FDC. I think this should help to explain all. Btw. I could not find any info, that 1050 is not supporting $4E/$4F commands.
  6. Thanks. It makes sense. I took a qiuck peek into 1050 ROM, and can say that info provided in link from 1'st post is absolutelly fabricated... maybe it match its bigger brothers drives (ST) but not 8bit, specially 1050. So i'll have to examine 1050 ROM, and TopDrive (easiest) ROM to find the proper track layout. or Just hook logic analyzer to my 1050 and have some fun
  7. Hello folks. I need to know a logical structure of DD atari floppy track. I found some info here: http://www.ataripreservation.org/websites/freddy.offenga/megazine/ISSUE6-FDTECH.html.. but it seems that is somehow wrong. As SD and ED looks reliable (SD/ED uses ca. 97% of theoretical capacity.), DD track exceeds theoretical limit of bytes on the track. Theoretical capacity is 6510 bytes/track for MFM encoding, alnd half of that for FM encoding. for DD track: 51+18*(112+256)=6675, its 165 bytes more that theoretical capacity ... Is there someone who can explain that? Or Could someone upload Kyroflux image of DD track ? (perfectly would be get it as MFM decoded stream) Or any other idea ? Br. willy.
  8. No. Sorry. Buyt you can send me an email and I will put you on a list.
  9. SOLD OUT. For now. There will be some more after easter, but unfortunatelly the price will be higher. Any question? Just ask me.
  10. Many people are asking me how to buy etc, so i started new thread: http://atariage.com/forums/topic/230666-skunkboard-sillyventure-edition-how-to-buy/
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