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Lorin Millsap

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Everything posted by Lorin Millsap

  1. Just some further updates. I have finished the assembly of the board along with the patches that Kevin has documented. It’s not working yet, and my schedule has been very full this week. I’ve ordered some parts I need to build a test rig, and I have a logic analyzer that I just got. So not much to report yet. But just in summary my test rig lets me get to the very basics and monitor and control many parts of the system. Sent from my iPhone using Tapatalk
  2. On that, the RAM works perfectly. For unpopulated chips there is no wrap around or skip. Reads from unpopulated chips will give erratic results, mostly random residual values. To check how much ram is present you need to write a non-random sequence then attempt to read that sequence back. If the sequence returned matches the sequence written that RAM is populated. Otherwise it is either unpopulated or there is a fault. Sent from my iPhone using Tapatalk
  3. Already been tried. It doesn’t have an effect. Sent from my iPhone using Tapatalk
  4. Sorry I guess I misunderstood the question then. It is a two layer board. Sent from my iPhone using Tapatalk
  5. No possibility of that. Yes it is a multi layer board. Sent from my iPhone using Tapatalk
  6. Indeed. In theory it should just work. But for some reason it isn’t. Sent from my iPhone using Tapatalk
  7. Well actually the schematics for the time being are classified. I of course have a copy, but Kevin has asked me not to share them and I will abide that. I am still assembling the board and then I will apply fixes to known bugs. Then I can start checking things with the scope and also use some other tools to see what I can learn. Sent from my iPhone using Tapatalk
  8. I figured it’s been a while since the last update. So I’m just letting you know where things are at. Kevin has sent me one of the prototype boards in the hopes that we can figure out why certain parts are not working. Timing on the ROM and RAM is stable, the two VIA chips are also stable. There is some odd behavior on the banking latches, and the audio and video are not working. We are certain it’s a timing issue and we will let you all know when that issue is resolved. By sending me a proto board the hope is that we have a second set of eyes since trying to debug it over email and phone calls isn’t very productive.
  9. Very nice. I would like a true parser but that’s probably not going to happen. Sent from my iPhone using Tapatalk
  10. Originally the 816 was our cpu choice but it was dropped for a variety of reasons. Sent from my iPhone using Tapatalk
  11. We are very familiar with this. It’s not something we want. Technically the statement isn’t exactly true either. CPLDs and FPGA have technical differences but those differences have little effect on end results. There are CPLDs that are more powerful and complex than some FPGAs. Both implement programmable logic and the difference is really just how the result is achieved. Sent from my iPhone using Tapatalk
  12. Very valid points. Making it MSDOS like May seem more familiar but will break compatibility with legacy IEC devices which is a design goal even if that doesn’t resonate with everyone. So I think these are excellent points to bring up and any mistakes do need to be corrected. Sent from my iPhone using Tapatalk
  13. The keyboard (and mouse) driver is being improved and yes there are a couple ideas bouncing around on that but the most prevalent is to set the driver to have two modes. The main default mode works like the setup we have now. Then the RAW mode pushes the actual RAW PS/2 data to the buffer instead of the interpreted codes. So to see if a certain key is being pressed you need only check the buffer. However that code hasn’t been written yet as the dev team has been very busy on other projects. Sent from my iPhone using Tapatalk
  14. I’m not posting this as an official update announcement as it’s not finished but wanted to whet your appetites. Also big shoutout to @Michael Steil and @Frank van den Hoef. Frank wrote the main driver which was way faster and more complete than the old one and Micheal extended its functionality. The next emulator release has major improvements to the DOS for the SD card filesystem. The main ones are: A lot of progress has been made with the X16 DOS. It's almost feature complete, and almost has feature parity with CMD floppy and hard drives. • Long filename support • You can open files for reading (OPEN2,8,2,"FILE") or for writing (OPEN2,8,2,"FILE,P,W"), read and write data, have four of them open at the same time, etc. etc. • Overwriting files is done with "@:". • You can copy files (DOS"C:BACKUP=ORIGINAL"), concatenate files (DOS"C:ALL=FILE*"), all with wildcards. • You can rename files (DOS"C:NEW=OLD"). • You can delete files (DOS"S:R*,Q*"). • You can lock/unlock files (DOS"L:R*" or DOS"F-L:R*"/DOS"F-U:R*"). • Like on CMD devices, create directories (DOS"MD:DIR), delete them (DOS"RD:DIR), change them (DOS"CD:DIR). • You can use paths everywhere (DOS"C//BACKUP/:FILE.TXT=FILE.TXT", DOS"$//BACKUP/:A*") • All commands and paths support drive/media numbers (DOS"$1:*"), but only 0 (current) and 1 (only supported partition) work. • You can get partitioning info (DOS"GP"+CHR$(1)) like on CMD hard disks. • You can even read/write DOS memory and execute code in a DOS context (M-R, M-W, M-E). Yeah, not that useful. • All error messages on the status channel (just type "DOS") are consistent with 1541/1571/CMD drives, e.g. 01, FILES SCRATCHED,05,00 etc. What's missing: • Open file for appending (,P,A). • Show/change disk name. • mkfs (N) • fsck (`V') • timestamp support What's missing that I'm not sure should be added: • REL files • block read/write API Sent from my iPhone using Tapatalk
  15. That already exists and it will absolutely work as is. Sent from my iPhone using Tapatalk
  16. An external SPI option I think is a good compromise especially if an SPI 2,4, or 8 implementation can be done. The single SPI using a shift register should be adequately fast as well. Sent from my iPhone using Tapatalk
  17. Please keep this thread on topic. We are discussing RS232 serial, not PS/2. Sent from my iPhone using Tapatalk
  18. NMI is reserved for PS/2. Technically you could snag it. Basically there are 2 6522s. The first one handles the PS/2 ports, joysticks, and the IEC bus. This VIA has its IRQ wired to NMI because we found that PS/2 was not working on all keyboards due to timing issues largely caused by IRQ handling delays. By moving it to NMI that eliminated audio, video, and other events from the IRQ and allows the KERNAL to assume that the only NMI events are keyboard or mouse related. If you enable a TIMER in VIA 1 it could be used as a watchdog. You’d just have to hook into the NMI loop. Are you guys opposed to an SPI UART? Sent from my iPhone using Tapatalk
  19. I don’t know how you figure. Firstly the high RAM is controlled with $0000 and $0001, with $0000 controlling which of the 256 possible banks is currently selected. But in the previous setup disabling does not create a 257th possibility. It is the same as bank0. As to injecting the IRQ and NMI handlers as far as I knew there is already an injection point located in RAM. Sent from my iPhone using Tapatalk
  20. 1. To do so would make the logic more complex. This ends up being the same two ZP locations the C64 uses anyway. 2. We looked at mapping IO elsewhere but found that doing so adds a lot more complexity which slows everything down and uses more parts. Having more contiguous memory doesn’t make sense if it’s not actually contiguous. Sent from my iPhone using Tapatalk
  21. Actually that’s no longer true. The banking is done without using the VIAs at all. It is now selected using latches shadowed at $00 and $01. This freed up the valuable VIA pins. Sent from my iPhone using Tapatalk
  22. Well short answer is it doesn’t have it. Technically remapping and banking are not the same thing. And remember the X16 is supposed to be simple. Sent from my iPhone using Tapatalk
  23. Because it wasn’t excluded. It would have to be implemented. Those are cpu functions and the X16 doesn’t have a MMU. Sent from my iPhone using Tapatalk
  24. Neither can be relocated under the current model. Sent from my iPhone using Tapatalk
  25. Sorry. You are correct. The other shift register is in the other VIA and it is not available. Sent from my iPhone using Tapatalk
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