Fixing STE microwire "mixer" error

Troubles with your machine? Just want to speak about the latest improvements? This is the place!

Moderators: Mug UK, Zorro 2, Greenious, spiny, Moderator Team

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Fixing STE microwire "mixer" error

Postby AtariZoll » Tue Jan 20, 2015 7:48 pm

Some people observed problems with unbalanced audio volumes of PSG and DMA by STE, Mega STE years ago . There should be possible to set PSG volume -12db with microwire in SW, but it never worked - I talk about serious sources like Atari ProfiBuch.
I looked today schematic of microwire in STE, and there is something very wrong.
viewtopic.php?f=16&t=27440
Correction took some 15 minutes:

STEmicrwFix.png


And proper setting of microwire mixer is not %01 for this, but %10 :D I wonder how this went this way in Atari . Seems that communication between SW and HW crews was bad.
Anyway, this correction is very useful. For instance, now sound quality in modded Xenon 2 is better, because PSG volume settings remain same, 4-bit, while I needed to lower them down, so used less bits, what made not so good volume changes by sound effects. And will help in other cases where DMA and PSG audio works simultaneously in STE.
You do not have the required permissions to view the files attached to this post.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Tue Jan 20, 2015 8:55 pm

How to perform fix: no need to desolder anything - just cut pin of resistor R531 which leads to 2 capacitors. Solder there, to resistor new 10K resistor, and other pin of it to point where R531 was soldered. Add shortcut from common point of 2 resistors to pin 5 of IC. That's all.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
exxos
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 4933
Joined: Fri Mar 28, 2003 8:36 pm
Location: England
Contact:

Re: Fixing STE microwire "mixer" error

Postby exxos » Tue Jan 20, 2015 9:09 pm

AtariZoll wrote:Some people observed problems with unbalanced audio volumes of PSG and DMA by STE, Mega STE years ago . There should be possible to set PSG volume -12db with microwire in SW, but it never worked - I talk about serious sources like Atari ProfiBuch.
I looked today schematic of microwire in STE, and there is something very wrong.
viewtopic.php?f=16&t=27440
Correction took some 15 minutes:
.


Ahh nice :) Have you tried a link instead of that 10K resistor ?

Also (if you haven't already) check that the bias has not voltage has not changed on the centre point of those 2 10K dividers.
4MB STFM 1.44 FD- VELOCE+ 020 STE - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - various clutter

http://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
http://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.
http://ataristeven.exxoshost.co.uk/Steem.htm Latest Steem Emulator

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Wed Jan 21, 2015 8:38 am

Exxos: what I wrote in other thread about shorting resistor was not good idea. But I left that text, with text of my first impression too - because this was really unexpected, shocking to see something like this. Only at second look on schematic I saw how really bad is it. This mod affects not voltage level of central point. This is just proper AC divider done with resistors.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

nichtsnutz
Atarian
Atarian
Posts: 6
Joined: Wed Oct 16, 2013 7:09 pm

Re: Fixing STE microwire "mixer" error

Postby nichtsnutz » Wed Jan 21, 2015 9:47 am

Hello AtariZoll,

some years ago I had taken measurements of the microwire interface of the ste.
I observed that I had to set the mask register always to $FFFF and set the data
as follows to get a correct communication as is described in the LMC1992 datasheet:

Bits [15..14] = '10' , microwire address of the LMC1992.
Bits [13..09] = '00000' , 5x dummy bits , they are allowed according to the datasheet.
Bits [08..06] = functioncode of the LMC1992.
Bits [05..00] = functionparameter of the functioncode.

here an image:

mw5.png


If you set a bit in the mask register to '0' then the microwire enable signal will go to '1'
and possible do a wrong initialization of the LMC1992 I think , because the datasheet
states that the falling edge of MW_ENABLE is the indicator of the communication start.
Here a possible wrong communication:

mw4.png


I hope this could help a little bit.

Vassilis
You do not have the required permissions to view the files attached to this post.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Wed Jan 21, 2015 10:05 am

Thanx nichtshutz, but I tried 4 different microwire setting codes already, and all worked fine - there were no lost, wrong bits. Setting was always same, proper. Schematic says everything, that's all what I can say. Really no point to talk more about microwire programming.

Here is YouTube video, recorded from mixer fixed machine. Now all sounds are well balanced, without any changes in game's PSG code. http://youtu.be/Ei_LF-oBl2A
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

nichtsnutz
Atarian
Atarian
Posts: 6
Joined: Wed Oct 16, 2013 7:09 pm

Re: Fixing STE microwire "mixer" error

Postby nichtsnutz » Wed Jan 21, 2015 10:21 am

Hello AtariZoll,

ok , good to know that the programming works , I was not sure , thank you !
So I will have to make the hardware change some day to my ste ...

Greetings ,
Vassilis

User avatar
qq1975b
Atari God
Atari God
Posts: 1077
Joined: Tue May 15, 2012 9:15 am
Location: Barcelona

Re: Fixing STE microwire "mixer" error

Postby qq1975b » Sun Jan 25, 2015 11:59 am

Is it possible to see a picture of the mod done, please? :oops:
I would like to avoid a missunderstanding on the modified schematics because I am not yet used to reading them completely. Thank you.
Trying to learn...

User avatar
exxos
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 4933
Joined: Fri Mar 28, 2003 8:36 pm
Location: England
Contact:

Re: Fixing STE microwire "mixer" error

Postby exxos » Sun Jan 25, 2015 12:09 pm

qq1975b wrote:Is it possible to see a picture of the mod done, please? :oops:
I would like to avoid a missunderstanding on the modified schematics because I am not yet used to reading them completely. Thank you.


It would probably be a good addition to the hardware stuff on my site to :)
4MB STFM 1.44 FD- VELOCE+ 020 STE - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - various clutter

http://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
http://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.
http://ataristeven.exxoshost.co.uk/Steem.htm Latest Steem Emulator

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Sun Jan 25, 2015 4:37 pm

There is picture, thanx to Anemos: http://forum.8bitchip.info/hardware-16/ ... %27-error/

I'm really not in mood to post here HW mods. Almost always threads were spammed by Simbo and with many posts - here some 10 :x
Next one will be on my forum, and here only link there .
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
troed
Atari God
Atari God
Posts: 1446
Joined: Mon Apr 30, 2012 6:20 pm
Location: Sweden

Re: Fixing STE microwire "mixer" error

Postby troed » Mon Jan 26, 2015 9:30 am

Awesome detective work and find.

Hippy Dave
Atari Super Hero
Atari Super Hero
Posts: 515
Joined: Sat Jan 10, 2009 5:40 am

Re: Fixing STE microwire "mixer" error

Postby Hippy Dave » Mon Jan 26, 2015 6:58 pm

AtariZoll wrote:Some people observed problems with unbalanced audio volumes of PSG and DMA by STE, Mega STE years ago . There should be possible to set PSG volume -12db with microwire in SW, but it never worked - I talk about serious sources like Atari ProfiBuch.
I looked today schematic of microwire in STE, and there is something very wrong.
viewtopic.php?f=16&t=27440
Correction took some 15 minutes:

STEmicrwFix.png


And proper setting of microwire mixer is not %01 for this, but %10 :D I wonder how this went this way in Atari . Seems that communication between SW and HW crews was bad.
Anyway, this correction is very useful. For instance, now sound quality in modded Xenon 2 is better, because PSG volume settings remain same, 4-bit, while I needed to lower them down, so used less bits, what made not so good volume changes by sound effects. And will help in other cases where DMA and PSG audio works simultaneously in STE.

After reading this, it appears you need a modded STE 'and' a modded Xenon 2 to get the right sound. I would call this a Xenon 2 bug, not a STE bug. Simbo's suggestions are better because they are more versatile.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Mon Jan 26, 2015 7:24 pm

Hippy Dave wrote:After reading this, it appears you need a modded STE 'and' a modded Xenon 2 to get the right sound. I would call this a Xenon 2 bug, not a STE bug. Simbo's suggestions are better because they are more versatile.


What you talk is pure nonsense. First of all - it can't be Xenon 2 bug because Xenon 2 has only PSG sound - therefore it can not have bug in sound level balance. Only could say that my Xenon 2 mod is buggy, because I'm stupid lamer, who can not do anything right, and I was not able to make it right :mrgreen:

Now let see the facts, what you, Hippy Dave could self to check: at least 2 people here said same as me: that PSG audio is much louder than DMA one, and that microwire setting for 12db lower PSG volume makes it muted instead. Then, since Atari self published that -12db mixer setting, we can deduct that is is because there was need for that. Because PSG level is not balanced with DMA audio level, and they used crap LM1992 chip which has no separate volume controls. I think that first error here is that default setting is bad. They should lower PSG level with 2 resistors, or add simple amplifier for DMA. Idea with 12db lower PSG level controllable by SW is not bad too, but is not supported in HW. Will not speculate again what could be the reason.

My HW mod is in perfect harmony with that optional 12db silencing. Harms nothing, because default setting is still same. As time passes there will be more SW what can benefit from that. And people too. Those who came here with ridiculous arguments must not do this mod. Please start own thread with your ideas and solutions, SW what can use it. I guess that it's easier to add some modded PCI PC audio card :lol:

Ahh, and here is very cheap and versatile idea: instead this mod add variable resistor (potenciometer) to PSG output, before capacitors leading to microwire - than can adjust it as you like any time, any SW.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
exxos
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 4933
Joined: Fri Mar 28, 2003 8:36 pm
Location: England
Contact:

Re: Fixing STE microwire "mixer" error

Postby exxos » Mon Jan 26, 2015 7:41 pm

I agree with AtariZoll. Imagine 2 audio sources, DMA, PSG going into a "mixer" chip, only the DMA line is going via a 100K resistor. What is the outcome ? DMA is a lot quieter than PSG audio. That is the problem. Its pretty much a BUG in the Atari HARDWARE itself. I think its awesome that AtariZoll found this problem and did a simple fix for it. Also shows that nobody else since STE was first made has even noticed this problem!
4MB STFM 1.44 FD- VELOCE+ 020 STE - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - various clutter

http://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
http://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.
http://ataristeven.exxoshost.co.uk/Steem.htm Latest Steem Emulator

User avatar
Anemos
Obsessive compulsive Atari behavior
Obsessive compulsive Atari behavior
Posts: 127
Joined: Sat Sep 27, 2008 1:14 pm
Location: Greece
Contact:

Re: Fixing STE microwire "mixer" error

Postby Anemos » Mon Jan 26, 2015 8:58 pm

So the mod works as it should, gives very good sound in modded Xenon, but trying some other games seems to have generally improved the sound, that in some as I said, maybe might use the DMA channel dunno.
Atari 1040 STE - 4mb - TOS 1.62
Atari 1040 STF - 1mb - TOS 1.00

mikro
Hardware Guru
Hardware Guru
Posts: 2018
Joined: Sat Sep 10, 2005 11:11 am
Location: Kosice, Slovakia
Contact:

Re: Fixing STE microwire "mixer" error

Postby mikro » Sat Feb 04, 2017 3:01 am

AtariZoll wrote:And proper setting of microwire mixer is not %01 for this, but %10 :D

Can you explain this in more detail, please? %01 is documented as "DMA + YM2149" (original volumes), while %10 means "DMA only". How that could be correct setting for bad YM volume?

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Mon Feb 06, 2017 9:15 am

mikro wrote:
AtariZoll wrote:And proper setting of microwire mixer is not %01 for this, but %10 :D

Can you explain this in more detail, please? %01 is documented as "DMA + YM2149" (original volumes), while %10 means "DMA only". How that could be correct setting for bad YM volume?

Of course, that stays for modded mixer, not for original circuit . Btw. I don't see much sense in muting YM in mixer. You can mute it simply by controlling YM chip - like writing 0-s to all sound registers.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

mikro
Hardware Guru
Hardware Guru
Posts: 2018
Joined: Sat Sep 10, 2005 11:11 am
Location: Kosice, Slovakia
Contact:

Re: Fixing STE microwire "mixer" error

Postby mikro » Mon Feb 06, 2017 9:58 am

AtariZoll wrote:Of course, that stays for modded mixer, not for original circuit . Btw. I don't see much sense in muting YM in mixer. You can mute it simply by controlling YM chip - like writing 0-s to all sound registers.

So what happens if I write %00 to the Microwire while having your fix? Still muted? Also, %01 means the original volume levels with your fix? (i.e. YM too loud)

And on the same token, you mentioned somewhere that one can swap lines leading to pins 4-5 and 25-26 and get default (I guess %01) fixed volume levels, how are other bit combinations affected in such case?

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Mon Feb 06, 2017 11:44 am

It does not affect STE default mixing - when YM level is louder.
Bit combinations are, for original HW:
0 0 = DMA + (YM2149 - 12 db) - but it works not, YM level is still 0 db
0 1 = DMA + YM2149 - that would be default mode
1 0 = DMA only - don't see that was ever used
1 1 = reserved

With mod, you need to set mixer mode 10, only then YM level will be lowered. If you swap those lines, then lowered volume will be default mode - that may be helpful for those complaining on to high audio level on RCA connectors.
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

User avatar
Cyprian
10 GOTO 10
10 GOTO 10
Posts: 1701
Joined: Fri Oct 04, 2002 11:23 am
Location: Warsaw, Poland

Re: Fixing STE microwire "mixer" error

Postby Cyprian » Mon Feb 06, 2017 12:12 pm

"1 0 = DMA only - don't see that was ever used" could be useful for e.g. GEM DMA mod player for muting keyboard click
Lynx II / Jaugar / TT030 / Mega STe / 800 XL / 1040 STe / Falcon030 / 65 XE / 520 STm / SM124 / SC1435
SDrive / PAK68/3 / Lynx Multi Card / LDW Super 2000 / XCA12 / SkunkBoard / CosmosEx / SatanDisk / UltraSatan / USB Floppy Drive Emulator / Eiffel / SIO2PC / Crazy Dots / PAM Net
Hatari / Steem SSE / Aranym / Saint
http://260ste.appspot.com/

User avatar
BoNuS
Atari Super Hero
Atari Super Hero
Posts: 765
Joined: Mon Jan 19, 2009 12:45 pm
Location: The Netherlands
Contact:

Re: Fixing STE microwire "mixer" error

Postby BoNuS » Mon Feb 06, 2017 12:43 pm

I bumped into this "hardware error" during the programming of my game. Very annoying indeed.For the TT and STE version we had to UP the DMA samples and lower the samples in the chip music to overcome the problem, after I tried for (god knows how) long to solve it with the software settings...
Still doesn't sound as good as the Falcon but okay, it works....
http://bonus.home.xs4all.nl/
( I have just to much Atari stuff)

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Mon Feb 06, 2017 1:31 pm

Cyprian wrote:"1 0 = DMA only - don't see that was ever used" could be useful for e.g. GEM DMA mod player for muting keyboard click

Usual, and simpler way is to disable it via system variable at $484 - reset bit 2 .
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

AtariZoll
Fuji Shaped Bastard
Fuji Shaped Bastard
Posts: 2978
Joined: Mon Feb 20, 2012 4:42 pm
Contact:

Re: Fixing STE microwire "mixer" error

Postby AtariZoll » Mon Feb 06, 2017 1:35 pm

BoNuS wrote:I bumped into this "hardware error" during the programming of my game. Very annoying indeed.For the TT and STE version we had to UP the DMA samples and lower the samples in the chip music to overcome the problem, after I tried for (god knows how) long to solve it with the software settings...
Still doesn't sound as good as the Falcon but okay, it works....

Yes, in Falcon it is done properly. Lower sound quality than on Falcon ? Not surprising. Perhaps that LM chip self makes sound worse - it was intended for cheap TVs.
P.S.: I did not see SW where YM and DMA audio was used simultaneously. Can you give some examples ?
Famous Schrodinger's cat hypothetical experiment says that cat is dead or alive until we open box and see condition of poor animal, which deserved better logic. Cat is always in some certain state - regardless from is observer able or not to see what the state is.

mikro
Hardware Guru
Hardware Guru
Posts: 2018
Joined: Sat Sep 10, 2005 11:11 am
Location: Kosice, Slovakia
Contact:

Re: Fixing STE microwire "mixer" error

Postby mikro » Mon Feb 06, 2017 10:11 pm

AtariZoll wrote:It does not affect STE default mixing - when YM level is louder.
Bit combinations are, for original HW:
0 0 = DMA + (YM2149 - 12 db) - but it works not, YM level is still 0 db
0 1 = DMA + YM2149 - that would be default mode
1 0 = DMA only - don't see that was ever used
1 1 = reserved

With mod, you need to set mixer mode 10, only then YM level will be lowered. If you swap those lines, then lowered volume will be default mode - that may be helpful for those complaining on to high audio level on RCA connectors.

Thank you very much for the information.

Just out of curiosity, how hard is to make this "right", i.e. %00 would be lowered YM sound level with your mod and the rest as it used to be?

User avatar
BoNuS
Atari Super Hero
Atari Super Hero
Posts: 765
Joined: Mon Jan 19, 2009 12:45 pm
Location: The Netherlands
Contact:

Re: Fixing STE microwire "mixer" error

Postby BoNuS » Tue Feb 07, 2017 7:45 am

AtariZoll wrote:
BoNuS wrote:I bumped into this "hardware error" during the programming of my game. Very annoying indeed.For the TT and STE version we had to UP the DMA samples and lower the samples in the chip music to overcome the problem, after I tried for (god knows how) long to solve it with the software settings...
Still doesn't sound as good as the Falcon but okay, it works....

Yes, in Falcon it is done properly. Lower sound quality than on Falcon ? Not surprising. Perhaps that LM chip self makes sound worse - it was intended for cheap TVs.
P.S.: I did not see SW where YM and DMA audio was used simultaneously. Can you give some examples ?


Well in my game it's done, BeGEMeD. I don't know about anybody else trying it. And only on STE/TT ofcourse.
Big tip: Don't use the internal speaker, use external one's. Internal is really crap (totally useless in my opinion).
On the TT it sounds okay once the internal speaker is OFF...

I had to up the volume of the samples for the STE/TT so much that to be honest their a bit over the top.
But otherwise the YM sound is so loud that you can't hear the speech.
http://bonus.home.xs4all.nl/
( I have just to much Atari stuff)


Social Media

     

Return to “Hardware”

Who is online

Users browsing this forum: No registered users and 1 guest