One chip MSX improvement project

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By doctorxyz

Supporter (7)

doctorxyz's picture

04-05-2017, 22:47

I would like to suggest the following feature: A RGB-YPbPr converter (maybe on th9958 core), enabled/disabled by some Keyboard button combo. There is a link with the related code, I hope this helps:

By caro

Champion (511)

caro's picture

02-04-2018, 17:44

Updating OCM based on DevBoards:
1) The system boot loader has been modified - the boot process is displayed on the screen.
2) In addition to the initial start to power on and by pressing the KEY0 button, during which the system BIOS boots up,
there is a "warm" start without loading the BIOS on the KEY1 button and from the keyboard, by simultaneously pressing Ctrl + Alt + DEL.
3) I tried to implement the so-called "ScanLine" mode - for inclusion, in any VIDEO mode it is necessary to press SHIFT + PrtScr.

By Fabf

Champion (260)

Fabf's picture

02-04-2018, 20:57

Hi Caro
I can't open DE0-nano project with Quartus 13.0.1
I have this error :

Error (125048): Error reading Quartus II Settings File C:/Users/Fabf/Desktop/de0n_src_180402/emsx_top.qsf, line 330
	Info (125063): set_global_assignment -name ENABLE_CONFIGURATION_PINS OFF
Error (125048): Error reading Quartus II Settings File C:/Users/Fabf/Desktop/de0n_src_180402/emsx_top.qsf, line 331
	Info (125063): set_global_assignment -name ENABLE_BOOT_SEL_PIN OFF

By caro

Champion (511)

caro's picture

02-04-2018, 22:34

I'm using version 14.1 of Quartus II (64-bit), which was bundled with devkit DE0nano

By caro

Champion (511)

caro's picture

19-04-2018, 05:44

By erpirao

Paragon (1224)

erpirao's picture

11-05-2018, 20:32

I have a doubt in the zemmix / ocm / de1:
is the turbo-VDP still active?
I remember at the time, this table of HRA!
OCM (3.58 MHz mode, normal VDP) -------------------------
YMMM = 19797
HMMM = 19718
HMMV = 8237
LMMM = 14792

FS-A1ST (R800) -------------------------------------------- -----
YMMM = 16211
HMMM = 18961
7809 LMMM = 13541

OCM (3.58 MHz mode, VDP Turbo) ---------------------------
YMMM = 3596
HMMM = 3580
HMMV = 1267
LMMM = 3261

Hmm ..
The difference in speed seems to have the difference in each command.
but those who have the Zemmix tell me that you do not notice that much difference.

By gaula82

Resident (42)

gaula82's picture

14-05-2018, 14:20

@caro, long time DE1 MSX user here thanks to your fantastic work!
I have a petition some questions:
1) Could you please make VGA scanlines configurable via dip switches on the DE1? Or at least could you tell me how to modify the sources so VGA scanlines are ON by default?
2) The new MGLOCM.COM command does not work on current DE1 core. It is a very useful command to load ROMs! Could you update sources with latest KDL version so it works, please?
3) I have an spanish keyboard. How can I configure the core to use the right layout, please?

By Grauw

Ascended (10074)

Grauw's picture

04-12-2018, 23:40

Grauw wrote:

Crossposting a bug report from here:

Grauw wrote:
Avkooi wrote:

My setop is a One Chip MSX with multi mente. It is flashed with the latest stable KdL firmware. I use the following sound chips:

PSG/MSX-Music/SCC+ - emulated by OCM (emulated MegaFlashRom SCC+ in slot 2)
MSX-Audio - Toshiba HX-MU900 with MSX-audio ROM and 256K sample memory (thanks Bas!)
YM2151 - Yamaha SFG-05
YMF278B - Moonsound clone by Reprofactory (Thanks ericb!)

The only problem I encounter is the MSX-Audio isn't working when the SFG-05 is inserted in the other slot. It plays fine when the Moonsound is inserted, but not in combination with the SFG. It just doesn't show up in VGMPlay. Are these chips sharing ports or something, or did I do something wrong? (BTW: Unknown Reality doesn't even start if the SFG module is connected)

The SFG and Music Module should not conflict, and they work fine together on my turboR. However I can indeed reproduce the problem you experience on my Zemmix Neo.

After looking into it a bit further, it appears to be an OCM bug; the MSX-AUDIO detection is very simple, it simply reads I/O port C0H and expects the value 6. However, when the SFG is inserted, the value 0 is returned and thus the MSX-AUDIO is not detected, and VGMPlay does not try to play on it.

More strangely though, when I check the value from Basic with ?INP(&HC0) it does return 6. Turns out that in assembly code, when I use in a,(0C0H) it returns 0, but when I use ld c,0C0H ; in a,(c) it does return 6, while that should make no difference whatsoever. So there seems to be a bus timing problem with this combination of modules in the OCM, that I can’t do much about.

Just to hail back to this old post;

It was later discovered that the Y8950 MSX-AUDIO status register’s bits 1-2 are not returning a high signal, but rather are hi-z (not connected). That means they depend on whatever happens to be on the bus at the moment that it’s read. Usually this is 1 due to pull-up resistors, but this is not guaranteed.

So, there is no OCM issue. Nowadays the VGMPlay MSX-AUDIO detection has been amended to take this into account. Other software should also not rely on reading 06H from the status register to detect the MSX-AUDIO (though they often do).

By Tabajara-Labs

Expert (95)

Tabajara-Labs's picture

06-04-2019, 10:32

Has anyone redrawn the schematics on eagle and willing to share? I don't want to redo everything....Thanks! Smile


Champion (271)

HRA!'s picture

18-11-2019, 21:45

Good day!

I am back in OCM development.
I got DE0-CV and DEOCM.
It has a larger FPGA than OCM.

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