7 MHz test.kitune-san wrote: ↑Tue Jul 12, 2022 11:58 pm I am trying 7MHz on the core right now.
It will take time.
Wait.
Will not work except for 8088BIOS due to problems with DMA address switching.
7 MHz test.kitune-san wrote: ↑Tue Jul 12, 2022 11:58 pm I am trying 7MHz on the core right now.
It will take time.
Wait.
Can you share how you are achieving 7Mhz?kitune-san wrote: ↑Thu Jul 14, 2022 4:18 pm7 MHz test.kitune-san wrote: ↑Tue Jul 12, 2022 11:58 pm I am trying 7MHz on the core right now.
It will take time.
Wait.
Will not work except for 8088BIOS due to problems with DMA address switching.
I know, but it's possible to do a nick/name search when writing a PM. Won't hurt to try and contact these folks here or ask on Discord. I won't myself coz I wouldn't know what exactly to ask for...
CRT SCR$ Project - building a collection of high-quality photos of CRT displays
CRT ART Books - retro-gaming books with authentic CRT photos
I changed biu_max.v to run on the edge of the CPU clock.MicroCoreLabs wrote: ↑Thu Jul 14, 2022 4:25 pmCan you share how you are achieving 7Mhz?kitune-san wrote: ↑Thu Jul 14, 2022 4:18 pm7 MHz test.kitune-san wrote: ↑Tue Jul 12, 2022 11:58 pm I am trying 7MHz on the core right now.
It will take time.
Wait.
Will not work except for 8088BIOS due to problems with DMA address switching.
In the current design, as the clock frequency is increased, the sdram read time exceeds the machine cycle time.MicroCoreLabs wrote: ↑Thu Jul 14, 2022 5:03 pmWhy is this?Achieving speeds faster than 7 MHz is more difficult with SDRAM.
SDRAMs usually have sub 100ns access times and the controller is running at 100Mhz, correct? So shouldn't we be able to perform a complete read/write cycle to the SDRAM within a single 8088 clock cycle? Maybe two? Im confused why the increasing the 8088 bus speed would have much of an effect on the SDRAM access time.In the current design, as the clock frequency is increased, the sdram read time exceeds the machine cycle time.
The Ready signal can be used, but the effect of increasing clock frequency is reduced.
I have merged these changes with the latest changes from the prebeta 1.4 branch, into a new experimental branch called prebeta 1.4-7mhz.kitune-san wrote: ↑Thu Jul 14, 2022 4:43 pm Please do not merge this code into the main as it is still experimental.
Not at the moment, when the core becomes part of the official MiSTer repository it will be evaluated, the thing is that changes have to be made to the framework (MiSTer_Main) to support this feature, it has already been thought about, and it is interesting.wark91 wrote: ↑Thu Jul 14, 2022 6:44 pm For the boot.rom containing the bios and IDE-XTL, it could be great to have two boot roms (for example boot.rom and boottandy.rom).
If on OSD "Model Tandy 1000" is selected and at the reset it will load boottandy.rom and the other case it will be boot.rom.
What do you think ?
A bit off topic but the first 286's and 8088/86 are more or less in the same league, 286 is much more advanced in some features, but not too much.
A separate thread was created for all this discussion.Mills wrote: ↑Thu Jul 14, 2022 7:35 pmA bit off topic but the first 286's and 8088/86 are more or less in the same league, 286 is much more advanced in some features, but not too much.
386 is a different story, also it is 32 bit, and ao486 does a great job recreating that.
I tested it and I'm very happy that it got a lot faster. But the speed of the "prince of persia" is still awkward. Perhaps if you improve the speed to 10Mhz, I’ll be able to play fairly smoothly then. Thank you for your hard workspark2k06 wrote: ↑Thu Jul 14, 2022 5:55 pmI have merged these changes with the latest changes from the prebeta 1.4 branch, into a new experimental branch called prebeta 1.4-7mhz.kitune-san wrote: ↑Thu Jul 14, 2022 4:43 pm Please do not merge this code into the main as it is still experimental.
This way, all users will be able to make use of the 7Mhz coupled with the latest changes with COVOX/DSS and UART up to 921.6K:
https://github.com/spark2k06/PCXT_MiSTe ... 51af85551e
The improvement is very noticeable in games like Prince Of Persia, or Titus The Fox:
PREBETA_1_4_7MHz.jpg
MiSTer_PCXT_7MHz.jpg
I use 6.22 and double dragon works well, I was told dos 6.22 does not use more ram that older version, it even uses less ram than others like version 5 for example.
https://ctrl-alt-rees.com/2021-01-06-wh ... emory.html
Code: Select all
MS-DOS
Version Bytes Total Bytes Free Bytes Used Notes
3.30 654,336 599,360 54,976
3.31 654,336 598,384 55,952 Support for HDD partitions over 32MB
4.00 655,360 563,088 92,272
4.01 655,360 569,296 86,064
4.01c 655,360 588,464 66,896
5.00 655,360 583,280 72,080 MS-DOS Editor (EDIT.COM) and QBasic added
5.00a 655,360 583,280 72,080 Bugfix release for the above
6.00 655,360 582,192 73,168 New disk utlities, DoubleSpace disk compression
6.20 655,360 581,472 73,888
6.21 655,360 581,472 73,888 DoubleSpace removed
6.22 655,360 581,472 73,888 DriveSpace added
IBM PC-DOS
Version Bytes Total Bytes Free Bytes Used Notes
1.00 654,336 642,192 12,144
1.10 654,336 641,936 12,400 Double sided disk support
2.00 654,336 629,648 24,688 Hard Disk Drives, subdirectories, device drivers
2.10 654,336 629,648 24,688
3.00 654,336 615,440 38,896 Support for larger disks
3.10 654,336 615,408 38,928 Networking support
3.20 654,336 608,368 45,968 3.5” 720K floppy support
3.30 654,336 599,504 54,832 3.5” 1.44MB floppy support, extended partitions
4.00 655,360 564,656 90,704 DOS Shell, EMS 4.0 support
4.10 655,360 564,640 90,720
5.00 655,360 583,248 72,112
5.00.1 655,360 583,232 72,128
5.02 655,360 581,696 73,664
6.1 655,360 590,768 64,592 First version after split with MS
6.3 655,360 590,752 64,608 SuperStor Disk Compression added
7.0 655,360 591,568 63,792 Memory optimizations, Stacker disk compression, Rexx
2000 655,360 591,488 63,872
does the double dragon work dos 6.22 in PCXT_PREBETA_1_4_7Mhz?
does the double dragon work dos 6.22 in PCXT_PREBETA_1_4_7Mhz?flynnsbit wrote: ↑Fri Jul 15, 2022 2:44 pmhttps://ctrl-alt-rees.com/2021-01-06-wh ... emory.html
Code: Select all
MS-DOS Version Bytes Total Bytes Free Bytes Used Notes 3.30 654,336 599,360 54,976 3.31 654,336 598,384 55,952 Support for HDD partitions over 32MB 4.00 655,360 563,088 92,272 4.01 655,360 569,296 86,064 4.01c 655,360 588,464 66,896 5.00 655,360 583,280 72,080 MS-DOS Editor (EDIT.COM) and QBasic added 5.00a 655,360 583,280 72,080 Bugfix release for the above 6.00 655,360 582,192 73,168 New disk utlities, DoubleSpace disk compression 6.20 655,360 581,472 73,888 6.21 655,360 581,472 73,888 DoubleSpace removed 6.22 655,360 581,472 73,888 DriveSpace added IBM PC-DOS Version Bytes Total Bytes Free Bytes Used Notes 1.00 654,336 642,192 12,144 1.10 654,336 641,936 12,400 Double sided disk support 2.00 654,336 629,648 24,688 Hard Disk Drives, subdirectories, device drivers 2.10 654,336 629,648 24,688 3.00 654,336 615,440 38,896 Support for larger disks 3.10 654,336 615,408 38,928 Networking support 3.20 654,336 608,368 45,968 3.5” 720K floppy support 3.30 654,336 599,504 54,832 3.5” 1.44MB floppy support, extended partitions 4.00 655,360 564,656 90,704 DOS Shell, EMS 4.0 support 4.10 655,360 564,640 90,720 5.00 655,360 583,248 72,112 5.00.1 655,360 583,232 72,128 5.02 655,360 581,696 73,664 6.1 655,360 590,768 64,592 First version after split with MS 6.3 655,360 590,752 64,608 SuperStor Disk Compression added 7.0 655,360 591,568 63,792 Memory optimizations, Stacker disk compression, Rexx 2000 655,360 591,488 63,872
After the uart HDD speed update, if I run Tetris (Spectrum Holobyte) on the pcxt core, the graphics break at a certain level. Is there any solution?spark2k06 wrote: ↑Sat Jul 16, 2022 8:02 am Updated prebeta 1.4 and prebeta 1.4 7mhz branches:
https://github.com/spark2k06/PCXT_MiSTe ... 0e641f0db7
https://github.com/spark2k06/PCXT_MiSTe ... c60fc7d9d8
The Tandy 320x200x16 mode is "high resolution", so identification and use of this mode is easy.
- CGA Mode Detection 320x200x4
Temporary solution for ghost lines in Tandy BIOS, switch to 200 lines with MODE 200 of Tandy MSDos 3.2:
I don't know, but I find it hard to believe that the reason is the increase in UART speed, if it happens "randomly", it would also happen earlier.suww37 wrote: ↑Sat Jul 16, 2022 12:34 pmAfter the uart HDD speed update, if I run Tetris (Spectrum Holobyte) on the pcxt core, the graphics break at a certain level. Is there any solution?spark2k06 wrote: ↑Sat Jul 16, 2022 8:02 am Updated prebeta 1.4 and prebeta 1.4 7mhz branches:
https://github.com/spark2k06/PCXT_MiSTe ... 0e641f0db7
https://github.com/spark2k06/PCXT_MiSTe ... c60fc7d9d8
The Tandy 320x200x16 mode is "high resolution", so identification and use of this mode is easy.
- CGA Mode Detection 320x200x4
Temporary solution for ghost lines in Tandy BIOS, switch to 200 lines with MODE 200 of Tandy MSDos 3.2:
spark2k06 wrote: ↑Sat Jul 16, 2022 12:49 pmI don't know, but I find it hard to believe that the reason is the increase in UART speed, if it happens "randomly", it would also happen earlier.suww37 wrote: ↑Sat Jul 16, 2022 12:34 pmAfter the uart HDD speed update, if I run Tetris (Spectrum Holobyte) on the pcxt core, the graphics break at a certain level. Is there any solution?spark2k06 wrote: ↑Sat Jul 16, 2022 8:02 am Updated prebeta 1.4 and prebeta 1.4 7mhz branches:
https://github.com/spark2k06/PCXT_MiSTe ... 0e641f0db7
https://github.com/spark2k06/PCXT_MiSTe ... c60fc7d9d8
The Tandy 320x200x16 mode is "high resolution", so identification and use of this mode is easy.
- CGA Mode Detection 320x200x4
Temporary solution for ghost lines in Tandy BIOS, switch to 200 lines with MODE 200 of Tandy MSDos 3.2:
Is there anything that depends on the UART clock other than the UART itself?spark2k06 wrote: ↑Sat Jul 16, 2022 2:16 pm I insist, it seems strange to me that it is a problem of the UART speed, but is it possible that you are using the experimental 7Mhz version? That might make more sense.
In any case, if it's the UART speed, it's not necessary to change the core, in the script set it to 115.2K and it will work anyway, but at the previous speed.