Setting CPU speed by software

By vanfanel

Champion (446)

vanfanel's picture

24-06-2010, 20:06

Hello there again!

I've found that I've to set my cpu speed at 3.75Mhz for Metal Gear and Gradius (for example) to run at the correct speed.
That's great, except that my MSX doesn't have an external turbo switch (it's FPGA-based computer and it's inside a home-made wooden box).

So, is there any small MSX-DOS program to set the CPU speed? ROMLOAD is supposed to do the work with the /T:0 parameter, but I don't see ths parameter has any actual effect at all!

regards

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By nikodr

Paladin (748)

nikodr's picture

24-06-2010, 21:17

taken from http://map.grauw.nl/resources/msx_io_ports.php

LD A,8
OUT (040H),A ;out the manufacturer code 8 (Panasonic) to I/O port 40h
IN A,(040H) ;read the value you have just written
CPL ;complement all bits of the value
CP 8 ;if it does not match the value you originally wrote,
JR NZ,Not_WX ;it is not a WX/WSX/FX.
XOR A ;write 0 to I/O port 41h
OUT (041H),A ;and the mode changes to high-speed clock

I think you need to change that code.The above code changes from 3.75 to 5.37

I think Nyyrikki would be the one to ask regarding such stuff :)

By Tanni

Hero (556)

Tanni's picture

25-06-2010, 15:13

Vanfanel, can you privide a picture from that FPGA in its wooden box?

By vanfanel

Champion (446)

vanfanel's picture

25-06-2010, 19:21

Sure!

http://www.flickr.com/photos/50145424@N03/4733602108/

It has drilled holes for the connectors in their exact places. Tell me if you need more or better pics!

By RetroTechie

Paragon (1563)

RetroTechie's picture

25-06-2010, 20:59

If that's a 1chipMSX-in-a-wooden-box, you can set one of the dipswitches on the bottom (see here for details).

If that's not a 1chipMSX, we want to know everything about it! LOL!LOL!

By Tanni

Hero (556)

Tanni's picture

25-06-2010, 23:37

Just searched for ''steampunk'' today: http://de.wikipedia.org/wiki/Steampunk

There's a PC with unusual casing.

If you like to provide more, yes, it would be interesting! Thanks!

By vanfanel

Champion (446)

vanfanel's picture

26-06-2010, 11:44

Well, here's my photo stream on flickr. There, you can see more pics about my MSX (NOT an PCM, but an ALTERA DE1 on a wooden box).

http://www.flickr.com/photos/50145424@N03/

Please ignore the pics of me handing a TEKKEN3 arcade rom board and a pirate zapper :D Just look at the pics at the beggining of the page.
There you can see the wooden box I used, the holes I made for connectors, and some games I play in this MSX:
-Penguin Adventure
-Space Manbow in MSX2+ glory
-Snatcher, installed to HD

All in all, it's an MSX with 4MB RAM, HD and new hardware :D

The ALTERA DE1 can be easily purchased in spain, it's around 140-Euros, and it's a VERY cool FPGA board.

By vanfanel

Champion (446)

vanfanel's picture

26-06-2010, 11:44

Well, here's my photo stream on flickr. There, you can see more pics about my MSX (NOT an PCM, but an ALTERA DE1 on a wooden box).

http://www.flickr.com/photos/50145424@N03/

Please ignore the pics of me handing a TEKKEN3 arcade rom board and a pirate zapper :D Just look at the pics at the beggining of the page.
There you can see the wooden box I used, the holes I made for connectors, and some games I play in this MSX:
-Penguin Adventure
-Space Manbow in MSX2+ glory
-Snatcher, installed to HD

All in all, it's an MSX with 4MB RAM, HD and new hardware :D

The ALTERA DE1 can be easily purchased in spain, it's around 140-Euros, and it's a VERY cool FPGA board.

By Tanni

Hero (556)

Tanni's picture

26-06-2010, 13:39

Nice. Thank you!

By NYYRIKKI

Enlighted (6016)

NYYRIKKI's picture

27-06-2010, 10:34

@vanfanel

?derorrim era serutcip ruoy yhW

By vanfanel

Champion (446)

vanfanel's picture

27-06-2010, 20:58

NYYRIKKI

!wonk t'nod I, mac s'koobcam ym desu tsuj I