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Re: MSX2 Compatible Computer Project [message #7921 is a reply to message #7920] Sat, 22 August 2020 08:36 Go to previous messageGo to next message
muellerk is currently offline  muellerk
Messages: 32
Registered: February 2019
Member
> Well, I use the F4 / FMPAC module as a mixer input in OMEGA: U48. I connect the AMP -GND output of the FMPAC to pins 2-4 of U48.

yes you can, but a additional summing-R for U48 is needed: see Summing_R-Network_U48.png

> Is it safe to do this with the circuit you send me?
> What security measure could I take, do I compare the signals with the oscilloscope?

1. you should delete the marked resistor in the schematic: see Modified2_Sound-Interface.png
2. you should measure the amplitude that are feed to the summing network of U48 from the F4/FM-Pack. The amplitude should be in
the same range as from the other sound sources (that simplifies life). Check that the sum of all sources does not overdrive U48
on its output. If the amplitude needs some adjustment, try to adjust R3 & R4. Rxx for U48 should be left as is to keep the
voltage range the same for all inputs.

I have always a bad feeling using elkos when the DC potential on both legs is on the same level (due to the polarized nature of elkos). Check the DC-level on both sides, the (+)-leg should be more positive then the (-)-leg (obvious fact, but this thought is based on some very exciting personal experiences I had during my business life with this ;-) Wink. If this can't be garantieed try to use a film capacitor or two elkos in +][- -][+ series connection.

Kurt
Re: MSX2 Compatible Computer Project [message #7951 is a reply to message #7921] Tue, 08 September 2020 08:43 Go to previous messageGo to next message
jordi.solis is currently offline  jordi.solis
Messages: 111
Registered: March 2017
Senior Member
Thank you for your answer I didn't saw it until now.
I mentioned that I sue the AMP output, so it includes a resistor and capacitor like in your defined schema, good.
However the mixed sound from the FMPACK was too low and so I increased this by modifying R4 (like your Rxx) to 1k.
I don't know if that was risky but it actually works.
I can compare the current amplitude on the mixer and at the U48 output. Then I will probe what this schema does.
thank you.
Re: MSX2 Compatible Computer Project [message #7977 is a reply to message #7951] Sun, 20 September 2020 18:38 Go to previous messageGo to next message
jmannz is currently offline  jmannz
Messages: 7
Registered: September 2020
Junior Member
Hi
Another successful build here. Thank you for sharing.
I do have one strange issue. I have built a few cartridges and they seem to function if the rom file is 16K or less. I did see the post about reprogramming the GAL and have done this but the issue remains.
Have tried with PAL and NTSC bios with the same result. As i am yet to get a 32K file that works could somebody be so kind as to share or provide a link to a know good 32k rom file so i can test it.

Many Thanks
John

Update:
The 32k roms I have do work in a emulator but on the Omega

[Updated on: Fri, 25 September 2020 17:47]

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Re: MSX2 Compatible Computer Project [message #8001 is a reply to message #7977] Tue, 06 October 2020 11:56 Go to previous messageGo to next message
jmannz is currently offline  jmannz
Messages: 7
Registered: September 2020
Junior Member
Problem solved.
Seems my lack of MSX knowledge was the issue. Swopping the upper and lower halves of the 32K ROMS solved the issue.
Re: MSX2 Compatible Computer Project [message #8004 is a reply to message #7977] Tue, 06 October 2020 23:59 Go to previous messageGo to next message
jordi.solis is currently offline  jordi.solis
Messages: 111
Registered: March 2017
Senior Member
jmannz wrote on Mon, 21 September 2020 03:38
Hi
Another successful build here. Thank you for sharing.
I do have one strange issue. I have built a few cartridges and they seem to function if the rom file is 16K or less. I did see the post about reprogramming the GAL and have done this but the issue remains.
Have tried with PAL and NTSC bios with the same result. As i am yet to get a 32K file that works could somebody be so kind as to share or provide a link to a know good 32k rom file so i can test it.

Update:
The 32k roms I have do work in a emulator but on the Omega
Hi John,
You say you built some cartridges? What schematic did you use?
The problem may be with the connection design you are using. Does the /CS12 signal reach the enable chip correctly?
I have used the schematic of the MSXpi card. With a 32K ROM chip you can activate /CS1 and load a 16K game (first half of memory) activate /CS2 and load another 16K game (second half) or activate the /CS12 signal if you have a game that occupies 32K.
You can compare that scheme with yours to see if there are differences.

regards.
Re: MSX2 Compatible Computer Project [message #8008 is a reply to message #8004] Fri, 09 October 2020 20:48 Go to previous messageGo to next message
jmannz is currently offline  jmannz
Messages: 7
Registered: September 2020
Junior Member
Hi
Thanks for the reply.
I have vert simple cartridge PCB's with jumpers (No mapper or other chips). the selections are
select CS_1,CS_2 or CS_12 and connect to OE (Pin 22)

With CS_12 connected to Eprom OE (Pin 22) and halves swopped the rom works fine.
as this is a 27C512 I have 2 x 32k roms and can select them by setting A15 low or high

https://github.com/Wierzbowsky/SGC_ImageCreator was the reason i tried swopping the halves

Regards
John
Re: MSX2 Compatible Computer Project [message #8020 is a reply to message #4137] Tue, 13 October 2020 13:32 Go to previous messageGo to next message
martinmurphy30 is currently offline  martinmurphy30
Messages: 4
Registered: September 2020
Junior Member
Hi guys, I'm new here and have also built a working omega. I have recently made myself a copy of The Cure and patched it to work on my hx-10, however it crashes on my omega (both patched and original ROM files) anyone else had this issue?
Re: MSX2 Compatible Computer Project [message #8026 is a reply to message #8020] Fri, 16 October 2020 20:18 Go to previous messageGo to next message
jmannz is currently offline  jmannz
Messages: 7
Registered: September 2020
Junior Member
@martinmurphy30

What size is your rom file?.
Flick me copy or point me to obtain a copy and I will test it on my Omega.

Regards
John
Re: MSX2 Compatible Computer Project [message #8027 is a reply to message #8026] Sat, 17 October 2020 06:37 Go to previous messageGo to next message
martinmurphy30 is currently offline  martinmurphy30
Messages: 4
Registered: September 2020
Junior Member
Thanks for the reply John, the ROM is 48k and can be downloaded here:https://www.msxdev.org/msxdev-archive/msxdev05/
Will be interesting to see if it works for you.
Re: MSX2 Compatible Computer Project [message #8029 is a reply to message #8027] Sat, 17 October 2020 15:42 Go to previous messageGo to next message
jmannz is currently offline  jmannz
Messages: 7
Registered: September 2020
Junior Member
The Rom boots with the splash screen and then the next screen "Press fire" I don't have a joystick so no fire to press Smile
Then it restarts with the same sequence. So i can only assume this is normal behavior. This s the rom file as downloaded no patching.
Re: MSX2 Compatible Computer Project [message #8030 is a reply to message #8029] Sat, 17 October 2020 15:46 Go to previous messageGo to next message
jmannz is currently offline  jmannz
Messages: 7
Registered: September 2020
Junior Member
Next question.
Has anybody got a TDC:600 floppy controller or clone to work. Mine just goes to a blue screen. I have tried various rom versions all with the same result.
Could somebody be so kind as to test a TDC:600 in the Omega

Many Thanks
John
Re: MSX2 Compatible Computer Project [message #8033 is a reply to message #8030] Sun, 18 October 2020 09:15 Go to previous messageGo to next message
martinmurphy30 is currently offline  martinmurphy30
Messages: 4
Registered: September 2020
Junior Member
After the press fire screen it should play the video intro and music, if it just restarts then it appears to be some kind of incompatibility with the omega. my copy plays perfectly on my hx-10, but crashes on the omega. Which bios are you using? I'm using a NTSC bios but mite try a pal one to see if it makes any difference.
Re: MSX2 Compatible Computer Project [message #8034 is a reply to message #8030] Sun, 18 October 2020 09:18 Go to previous messageGo to next message
martinmurphy30 is currently offline  martinmurphy30
Messages: 4
Registered: September 2020
Junior Member
https://msxmakers.design.blog/proyectos/proyecto-tdc-600/
Jordi has tested the floppy controller on his omega and it works fine.
Re: MSX2 Compatible Computer Project [message #8037 is a reply to message #8034] Mon, 19 October 2020 02:05 Go to previous messageGo to next message
jmannz is currently offline  jmannz
Messages: 7
Registered: September 2020
Junior Member
martinmurphy30 wrote on Sun, 18 October 2020 09:18
https://msxmakers.design.blog/proyectos/proyecto-tdc-600/
Jordi has tested the floppy controller on his omega and it works fine.
Thank you
Re: MSX2 Compatible Computer Project [message #8038 is a reply to message #8034] Tue, 20 October 2020 07:14 Go to previous messageGo to next message
jordi.solis is currently offline  jordi.solis
Messages: 111
Registered: March 2017
Senior Member
martinmurphy30 wrote on Sun, 18 October 2020 18:18
https://msxmakers.design.blog/proyectos/proyecto-tdc-600/
Jordi has tested the floppy controller on his omega and it works fine.
Thanks
Re: MSX2 Compatible Computer Project [message #8039 is a reply to message #8038] Tue, 20 October 2020 07:15 Go to previous message
jordi.solis is currently offline  jordi.solis
Messages: 111
Registered: March 2017
Senior Member
I really had no idea that you were interested in my progress.
I don't know if you can understand or translate my blog. Thanks for your interest.
If someone wants to collaborate and help me by translating the content into English it would be wonderful.
I thought everyone here knew like me or even more.

I intend to extend the omega with FM / MUSIC, Turbo button, a disk drive without wasting a slot, designing a wide case for the extensions, and of course I do not have that much time, any help is welcome.

I would also like to build a BUS monitor cartridge with stop and go, step by step and logic test. Surely it doesn't fit, well on multiple cards.

[Updated on: Tue, 20 October 2020 07:17]

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