Jump to content

MIDIbox NES?


unsocial

Recommended Posts

Wikipedia says:

CPU: Ricoh 8-bit processor based on MOS Technology 6502 core' date=' custom sound hardware, and a restricted DMA controller on-die

    * Main RAM: 2 KiB plus expanded RAM if present on the cartridge

    * ROM: Up to 49128 bytes (just shy of 48 KiB) for ROM, expanded RAM, and cartridge I/O; bank switching can expand this by orders of magnitude

So it seems to use the chip outside the NES, you'd need to make a simple single board computer, based on other 6502 SBC projects, but designed for the pinout of the NES CPU, and with extra circuitry for the audio output.  Program just enough 6502 code into it to interface between the CPU and a Core board, then write a MIOS NES app. 

Simple  ::)

Link to comment
Share on other sites

  • Replies 64
  • Created
  • Last Reply

Top Posters In This Topic

Dont want to make any extra publicity but i own a MIDINES cart and it does the job for me,

a funny annectode is that theres a PIC inside of it :)

Ive modified a NES motherboard to fint in a 1U rack and soldered the stereo audio touts to RCA plugs on the chassis.

fun fun... But i plan on maybe adding a MIDIBox in front to allow for greater flexibility/arpegios and especially a polyphony-from-MiDIChannel hack.

Link to comment
Share on other sites

just that it's been said

for all the people with PAL version NES console who plan do buy a MIDINES.

It will work (after the CIC hack) but it's absolutely out of tune  :o

I just bought such a cardride and now I have to find a way to alter the NES cpu clock timing.  :'(

btw, my first post

cheers

e-toy

Link to comment
Share on other sites

just that it's been said

for all the people with PAL version NES console who plan do buy a MIDINES.

It will work (after the CIC hack) but it's absolutely out of tune  :o

I just bought such a cardride and now I have to find a way to alter the NES cpu clock timing.  :'(

Oh, thats very sad indeed. the tables are hardcoded with the NTSC pulse lenghts i guess.

But you could just buy a NTSC NES on ebay for 10 dollars, rip the innards and do something like this:

this thing is still a "playable" NES console, well if you can bother opening the rack mount each time you want change the cartridge :)

Web search for "portable NES" and youll get all the pinouts you need. I did the "stereo mod" and one of the many "video amplifiers" mods.

I also de-CIC 'ed it and placed a brand new ZIF connector.

I dont want to discourage anyone from making a MIDIBOX NES in any case. Just for me, my goal is to have MIDI versions of most/all

important late 70's and early 80's video game/computer sound chips, and this was, for me the shortest path for the NES, both finance, and time wise.

643_NESRACK_jpg208d869b0fdeec6ece4be2ed6

Link to comment
Share on other sites

just that it's been said

for all the people with PAL version NES console who plan do buy a MIDINES.

It will work (after the CIC hack) but it's absolutely out of tune  :o

I just bought such a cardride and now I have to find a way to alter the NES cpu clock timing.  :'(

There must be a timing oscillator or crystal on there somewhere you could change?

Or you could download Syntendo

%7Boption%7D

Link to comment
Share on other sites

  • 4 months later...

Seems like there were some good ideas here. Has anyone tried out building a single-board computer or tried integrating this into MBox stuff yet? The MIDI cartridge looks like it's probably going to be the best bet otherwise, although $90 + shipping seems like a lot of $$$ to throw down for a simple soundchip...

Link to comment
Share on other sites

like vedge said

this was, for me the shortest path for the NES, both finance, and time wise.

that's absolutley right. even if 90$ + seems to be lot of money, you will need much more (particularly time)to develop a new system based on MIOS.

In the meantime i found a solution to "tune" my PAL NES  :)

I used an LT1799 Frequency generator as Crystal substitution for the CPU clock. Now I can tune my console in a wide range.

greets

e-toy

Link to comment
Share on other sites

In the meantime i found a solution to "tune" my PAL NES  :)

I used an LT1799 Frequency generator as Crystal substitution for the CPU clock. Now I can tune my console in a wide range.

greets

e-toy

hey e-toy! can you describe in more elaborate detail the mod you did to your PAL NES? I also run Midines on a PAL NES and would really appreciate your advise!

Link to comment
Share on other sites

i had to reopen my NES to make a picture

With the pot on PIN 3 of LT1799 you can adjust the CPU clock frequency (tune)

right tune will be at arround 3,8K so you can use a 5k or 10k pot.

cables should be as short as possible. CPU clock frequency is about 28 Mhz.

Note that you wont get a picture out of the console anymore because the GPU will also be "tuned" and

TV cant sync anymore to this frequency.

greets

e-toy

PAL NES tunemod_thumb.gif

PAL NES tune mod2_thumb.jpg

1084_PAL_NES_tunemod_gif9e58413bb4b26158

1088_PAL_NES_tune_mod2_jpg9a786423338e72

Link to comment
Share on other sites

  • 2 weeks later...
  • 2 months later...

go ahead and try  ;)

for me graphics arn't really important, as I only need it for music purpose.

But you could easy make a simple hack to toggle between Gaming tune and Music tune. Just use two pots an a switch to toggle between the two different values.

Or even easier. Buy an NTSC Console! (and hope that your'e TV is able to display NTSC Video)

If someone knows an other working hack that alter the tune of sound without change the video frequency, let me know  ;)

Link to comment
Share on other sites

  • 2 weeks later...
  • 4 months later...
Quote
Actually, I know NOTHING about NES's, I don't even know if they generate sounds via the video chip as per the VIC or not, that's just what I would do.

 

NES' soundchip is builtin CPU. If your purpose is making a midibox with NES soundchip you can take NES' CPU. Sound out directly through pin 1 and 2 of NES' CPU.

 

For guy who want making music on real NES you can use a Nes tracker and test your tune on a special cartridge who use SD card for loading any game or Nes sound format. This cart is for using on Famicom hardware, but with an 60 to 72 pin adaptor you can use on US or PAL NES.

 

nessd1.jpg

nessd2.jpg

 

 

 

 

Edited by Dr.Wily
Link to comment
Share on other sites

  • 6 months later...
http://web.archive.org/web/20030805180424/http://greybox.norfair.org/proto_r4.jpg  <-- this would look nice sitting next to a midibox core inside a case.  if the circuitry is 3.8" x 6" or smaller i'll mill out a couple prototypes of the SBC MIDIbox_NES module boards ;)  i would like to hear what this can do!  i know the SID module sounds AMAZING!
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...