MSX HDMI mutlimedia card

Страница 30/56
23 | 24 | 25 | 26 | 27 | 28 | 29 | | 31 | 32 | 33 | 34 | 35

By maxis

Champion (512)

Аватар пользователя maxis

20-12-2014, 19:46

Grauw wrote:

maxis: Sounds great now! Smile

Excellent. Thanks, Grauw. So, I'll stop here with the audio HW development for now and concentrate on the graphics as the time will permit.

By lexmcfly01

Resident (64)

Аватар пользователя lexmcfly01

22-12-2014, 18:30

Crear work maxis! I can't belive it!

By lexmcfly01

Resident (64)

Аватар пользователя lexmcfly01

22-12-2014, 18:31

Great work! dam corrector...

By ivanovic

Rookie (22)

Аватар пользователя ivanovic

23-12-2014, 11:50

Just came across this thread today, this project looks very promising
Also Meteor webpage, specially the introductory post in http://meteor-m.com/wordpress/?page_id=48 are great, with clear and nice explanation of the goals.
Nice tribute to MSX!
Thanks Maxis!

By maxis

Champion (512)

Аватар пользователя maxis

24-12-2014, 00:08

@Lexmcfly01: Спасибо!
@Ivanovic: Thank you!

By maxis

Champion (512)

Аватар пользователя maxis

30-12-2014, 00:56

Dear MSX Gurus,

Do you know any MSX/MSX2/MSX2+/TR models in their standard configuration (non-modified), where the MSX slot CPUCLK is not provided by the VDP, but rather a free running clock?

For example, DAEWOO CPC400S(with digitizer, PAL version), YAMAHA YIS805 with digitizer can have an independent 3.579545 MHz clock oscillator installed as the factory option, which provides the clock to all the internal resources but fully asynchronous to the VDP. However, that option was never installed AFAIK.

Thank you,

By Grauw

Ascended (9379)

Аватар пользователя Grauw

30-12-2014, 18:46

maxis wrote:

Do you know any MSX/MSX2/MSX2+/TR models in their standard configuration (non-modified), where the MSX slot CPUCLK is not provided by the VDP, but rather a free running clock?

From what I understood, this applies to many or most MSX models?

By maxis

Champion (512)

Аватар пользователя maxis

30-12-2014, 23:26

Grauw wrote:
maxis wrote:

Do you know any MSX/MSX2/MSX2+/TR models in their standard configuration (non-modified), where the MSX slot CPUCLK is not provided by the VDP, but rather a free running clock?

From what I understood, this applies to many or most MSX models?

Normally on the wast majority of MSX computers, the SLOT and CPU CLOCK are generated by the VDP.
However, I would like to know what are the exceptions.
CPU CLK as VDP CLK derivative is currently required by Procyon in order to sync the MSX internal VDP to Procyon VDP model without an external video cable.
In the worst case, the external video cable between the MSX video out and Procyon sync in must be added (ugly but reliable). Almost all the MSX computers are equipped with RCA VIDEO output.

By rogermm

Master (130)

Аватар пользователя rogermm

31-12-2014, 17:48

Is MSX VDP 50/60Hz interrupt enough to get both VDP syncronized? Maybe a PLL using the 50/60Hz vertical signal as a reference frequency?

By maxis

Champion (512)

Аватар пользователя maxis

31-12-2014, 18:53

rogermm wrote:

Is MSX VDP 50/60Hz interrupt enough to get both VDP syncronized? Maybe a PLL using the 50/60Hz vertical signal as a reference frequency?

Unfortunately, the MSX slot bus doesn't output the VDP IRQ.

So currently Procyon runs the calibration loop only once at the MSX splash screen, which picks up the VSYNC interrupt and resets Procyon Vcounter accordingly. Then, all the tracking occurs by using CPU 3.57 MHz clock, knowing that it is either /6 clock derivative of 9938 or /3 derivative of 9918. PLL is already in use but to generate the 100 MHz clock from 3.57 MHz.
So, in the worst case, the HSYNC will be also in use for the GENLOCK. VSYNC can't be used due to the excessive phase noise.

Therefore, I either can use 3.57 MHz CPU clock if the CPU is synchronized to VDP, or the external CVBS from MSX video output. Unfortunately, I see currently no other solution possible. And I'd like to avoid using the external cable to connect the MSX video output to Procyon for synching.

Страница 30/56
23 | 24 | 25 | 26 | 27 | 28 | 29 | | 31 | 32 | 33 | 34 | 35