From: hardrock@underg.UUCP (hard rock) Subject: Sound Blaster MIDI port Date: 18 Feb 92 21:12:52 GMT I have downloaded a program called CHEAPMID.ZIP, I found it on Point of no return. I was just wondering if anyone else have tried to project. It is suppose to make the interface required to connect midi equipment to the sound blaster. Also when I went to buy the equipment, I could only find the 8 pin chip for the midi, and it talked about a 6 bit chip. Well here is the text for those who are interested. BTW, I haven't tried this out yet, I have created the model, but need some equipment to test it on. --- The following text explains how to build a MIDI interface for the Sound Blaster. The circuit is my own design, but works just like the commercialy available interfaces that retails for $60-$90. Here is the list of parts necessary: Qty. Part 1 Sharp PC900 or HP 6N138 opto-isolator 1 DB15P (15 pin 'D' connector, male. like joystick connector) 3 220 ohm resistors (2 for input, 1 for EACH output you need) 1 3 conductor shielded cable (length is up to you) 2 Female 5 pin DIN connector (1 for input, 1 for each output you need) 1 PC board with pre-drilled holes (about 2" x 2" from Radio Shack) A few short lengths of hook-up wire All of these parts, except the first 2, are available from Radio Shack. Construction techniques are completely up to you, if you want to go ultra-cheap, you don't even need a PC board or enclosure, and you could use a MIDI cable you already have by cutting it in the middle. I used a PC900 out of a non-working organ and cut the end off of a joystick I didn't need and built the whole thing for about $4.00. Buying all the parts new, and using an enclosure with built-in MIDI jacks may cost about $20 or so. Here is a diagram of the DB15P connector (looking at the solder side). 1 5 8 o o o o o o o o o o o o o o o 9 12 15 Here is the 5 pin FEMALE DIN plug (solder side). 2 5 o 4 o o 3 o o 1 This is the circuit for the MIDI INPUT. +-----> To pin 5 of 'D' connector | To pin 15 of 'D' connector <---+ | +-------+-----> To pin 9 of 'D' con | | | | |6 |5 |4 \ +---------------+ / 220 ohm | PC900 | \ resistor | or | / | o HP 6N138 | | +---------------+ +------> To pin 6 of PC900 |1 |2 |3 | | | \ | +-----> No connection 220 ohm / | resistor \ | / +-----> To pin 5 of DIN connector | To pin 4 of DIN connector <----+ Don't overlook the two 220 ohm resistors. Also, for cables longer than a few feet, connect pin 2 of the DIN to pin 5 of the 'D' connector. The output circuit is much simpler. 220 ohm resistor To pin 12 of 'D' connector <---------/\/\/\/\/---------> To pin 5 of DIN con. To pin 15 of 'D' connector <---------------------------> To pin 4 of DIN con. Also, for cables longer than a few feet, connect pin 2 of the DIN to pin 5 of the 'D' connector. This circuit has been built and tested by me, using Voyetra's SPJr, and a cheap-o Casio keyboard. The input and output do work as shown here, but I don't have any other MIDI devices to use to test using more than 1 output device. Theoretically, it should work fine, but it has not been tested. The chances of hurting anything by trying is slim and none. This circuit DOES work, but I make no guarantees, nor will I be held responsible for any damages you may cause from your use of this information. If you have any questions, or would like to buy one already built for you, I can be contacted on: The Lighthouse BBS (207) 255-3700 (username is Ronald Davis) The Music Studio BBS (708) 351-0288 (username is Volstagg) From: bl562@cleveland.Freenet.Edu (Gary P Gabriel) Subject: Re: Sound Blaster MIDI port Date: 20 Feb 92 02:33:01 GMT I built CHEAPMID board of which you speak. I could not get it to work. The Sharp chip was unavailable the the 6N26 is not a direct replacement for the Sharp (PC900?) chip. I found another set of plans, built it, and have used it with relative success. If I can remember where I got it I will post it. From: kdrenard@smoke.brl.mil (Kenneth D. Renard) Subject: Re: SoundBlaster MIDI port Date: 20 Feb 92 13:41:38 GMT I believe there is a mistake in the MIDI-out portion of this design in that pin 15 from the D-connector is the MIDI-in (see SB manual). Pin 12 should go through the 220 ohm resistor to DIN pin 5 as stated in the designs. I'm pretty sure that DIN pin 4 should be +5 volts. Connect it to pin 9 (instead of pin 15) from the D-connector through a 220 ohm resistor. I could not find a PC900 or HP 6N138 opto-isolator, but Mouser electronics crossed it to an NTE 3093 which happens to be an 8-pin DIP. Mouser was very helpful and sent me the pin-out which shows that 2 of the pins are not used. All I need now is the pinout for the HP 6N138 to compare the two. I just completed another design for the MIDI connector, but haven't worked the bugs out yet. I will try to post it soon. Ken Renard From: luthe@jach.hawaii.edu (Rusty Luthe) Subject: Re: SoundBlaster MIDI port Date: 21 Feb 92 10:26:13 GMT Have you tried to get the PC900 isolater from Mix publications? They have been selling them for quit awhile. Good Luck Rusty From: dev@hollywood.acsc.com Subject: SB MIDI circuits I have built the one with the PC900. Only MIDI-OUT works on my synth (I really haven't tested MIDI-IN). Dev Mazumdar dev@acsc.com ============================== A cheap MIDI connector box for the Sound Blaster card v1.2 March 22nd, 1991 by Adam Mirowski mir@chorus.fr ============================== Sound Blaster has a "built-in MIDI interface", but "all you need is a MIDI Connector Box (optionally available) in order to connect your SB to MIDI instruments or keyboards", says the add on the box. The list price for that gadget is as high as $79.95 and anyway it is not available here in France. Also, the MIDI interface is not compatible with the MPU-401 standard (and de facto norm) and is only one-way-at-a-time. So the box is not worth the money, except if you try to set up it by yourself. For $5 you can get the basic functionalities and for $10 everything which comes with the original one. I have heard on Usenet recently that Sound Blaster will soon come out with a standard MIDI interface. Chances are that this circuit will also work with that new version. ! Corrections (AM): SB Pro doesn't seem to be MPU compatible; ! it is already provided with a MIDI Adaptor ! that you can also purchase separately for $25 (probably for ! an old SB.) I suppose that the cabling of this MIDI adaptor ! corresponds to paragraph II of the "SUPPLEMENT" (see below.) ! I was also told that SB v2.0 has a bidirectional MIDI port. ! This could be also the case for SB Pro. Parts ===== Qty Name Type Tandy ref --------------------------------------------------- 1 Optocoupler 4N25 276-9294 3 Resistors 220 ohm 271-015 1 Resistor 1 Kohm 271-023 1 AND gate 74LS08 276-9276 2 DIN plugs Female 5 pins 274-9110 1 Canon DB plug Male 15 pins Not sold [1] Diode 1N914 or 1N4148 276-1122/276-9014 1 Veroboard (*) 5cm by 5cm 8 Wires Not shielded 1 Box to put all that stuff inside [] - didn't use it myself. (*) It is a piece of epoxide with a raster of holes spaced at 2.54mm. On one side there are preprinted copper tracks along each line of holes (in one direction only). You cut off unused portions of the tracks and join the other with straps, so as to get a primitive form of a printed circuit board. You then insert the electronic parts and solder them. Sound Blaster MIDI/Game connector REAL cabling ============================================== +------------------------------------------+ ! Pin Signal ! !------------------------------------------! ! 1 +5V ! ! 2 X button for joystick A ! ! 3 X potentiometer for joystick A ! ! 4 Ground ! ! 5 Ground ! ! 6 Y potentiometer for joystick A ! ! 7 Y button for joystick A ! ! 8 +5V ! ! 9 +5V ! ! 10 X button for joystick B ! ! 11 X potentiometer for joystick B ! ! 12 MIDI out ! ! 13 Y potentiometer for joystick B ! ! 14 Y button for joystick B ! ! 15 MIDI in ! +------------------------------------------+ The interesting pins are 12, 15, 4 (or 5) and 9 (or 8 or 1). BTW, if your joystick Y cable assumes that pin 12 is ground (as it is on a normal game port), it will not work with the SB. Interface cabling ================= The cabling is roughly the same as in the MIDI 1.0 Specification, except that I used a different optocoupler and "AND" gates instead of inverters (simply because Tandy sold the former with docs :-). Numbers between parentheses are pin numbers. ICs have a standard pin numbering scheme. Other parts have pin numbers written on them. For resistors, it's simply to make difference between the two ends. 6 5 4 +--!----!----!--+ Usually ! ! IC seen from the top a hole --> > ! ! ! +--!----!----!--+ 1 2 3 "MIDI-in", "MIDI-out" design the female MIDI plugs. "Game/MIDI" designs the 15 pin female connector on the SB. FROM PIN TO PIN MIDI input part --------------- MIDI-in (4) Resistor1 220ohm (1) Resistor1 220ohm (2) Optocoupler (1) Optocoupler (2) MIDI-in (5) [Optocoupler (1) Diode -] [Optocoupler (2) Diode +] Games/MIDI (9) Resistor4 1Kohm (1) Resistor4 1Kohm (2) Optocoupler (5) Games/MIDI (15) Optocoupler (5) Optocoupler (4) Game/MIDI (4) MIDI output part ---------------- Games/MIDI (12) AND gate (1) AND gate (1) AND gate (2) AND gate (3) Resistor2 220ohm (1) Resistor2 220ohm (2) MIDI-out (5) MIDI-out (4) Resistor3 220ohm (1) Resistor3 220ohm (2) Game/MIDI (9) Games/MIDI (9) AND gate (14) Games/MIDI (4) AND gate (7) Final remarks ============= When using a "veroboard", don't forget to cut tracks under the IC and the optocoupler, or they will be short-circuited. You will probably also want to setup two MIDI cords, to attach the interface to an instrument. To stay under $5, you could use male plugs instead of female ones for the interface and plug them directly into the instrument. When preparing the cords, be careful about not swapping the wires. The pin 4 from one plug must be wired to pin 4 from the other end, and the pin 5 must be attached to pin 5. None of the other pins must be wired, nor the overall cable shielded. There is no ground in MIDI cords. If you want more outputs, you have to slightly extend the MIDI output part. I would rather have only one AND gate input attached to the SB MIDI-out pin and only one MIDI-out plug per AND gate output. If Creative Labs offer 5 MIDI outs in the original Connector Box, it is probably because they use simple inverters (or buffers) and there are 6 per IC. As I previously said, I bought AND gates only because they had data sheets attached, whereas inverters/buffers had not... Direct your remarks to mir@chorus.fr, or to M. Adam Mirowski Chorus systemes 6, avenue Gustave Eiffel F-78182 Saint-Quentin-en-Yvelines CEDEX FRANCE My phone number is +33 (1) 30-64-82-00 I obviously won't take any responsibility for the damages you could do to your Sound Blaster or to your MIDI equipment while using this interface. SUPPLEMENT ---------- I) You can use invertors in place of AND gates. The schematic diagram would be the following (for 2 outputs), instead of the old "MIDI output part" description. !\ !\ SB ! \ 2 ! \ 4 +--------+ 5 MIDI 4 +--------+ SB MIDI ---! >o--+---! >o----! R=220 !----[ out ]---! R=220 !---- +5V out 1! / ! 3! / +--------+ plug 1 +--------+ (pin 9) 12 !/ ! !/ ! ! ! !\ ! ! \ 6 +--------+ 5 MIDI 4 +--------+ SB +---! >o----! R=220 !----[ out ]---! R=220 !----- +5V ! 5! / +--------+ plug 2 +--------+ (pin 9) ! !/ ! ! +--- etc. Pin 14 of the chip must be connected to +5V, and pin 7 to ground, just like with the previous one. Also don't forget to remove the strap between old pins 1 and 2! It is no more necessary and would court- circuit the first inverter. The other inverters in the chip are cabled between pins 13 (input) and 12 (output), 11 and 10, 9 and 8 (all the inverters point to the right). If you try to use CMOS inverters (4... series) instead of TTL ones (74.. and 74LS... series), please remark that CMOS inverters "point" to the left. Tandy references are different for 74.., 74LS.. and 74HC.. circuits. II) If you really want to save money, don't put any AND gate. Connect together the wires going to pins 1, 2 & 3. Don't short-circuit the power supply pins; leave them unconnected. III) For the optocoupler, you could also use a 4N26, a 4N27 or a 4N28. -- Adam Mirowski, mir@chorus.fr (FRANCE), tel. +33 (1) 30-64-82-00 or 74 Chorus systemes, 6, av.Gustave Eiffel, 78182 Saint-Quentin-en-Yvelines CEDEX From rjf@gdwb (Rex Foord) Tue Dec 8 13:48:54 1992 From: rjf@gdwb.oz.au (Rex Foord) Newsgroups: comp.sys.ibm.pc.hardware,comp.sys.ibm.pc.soundcard,rec.music.synth,comp.music,sci.electronics Subject: Re: Looking for that Sound-Blaster to MIDI circuit again. Message-ID: <3442@peking.gdwb.oz.au> Date: 6 Dec 92 11:44:14 GMT References: <1992Dec1.065123.6001@julian.uwo.ca> Followup-To: comp.sys.ibm.pc.hardware Lines: 71 Nntp-Posting-Host: lewis.isd.gdwb.oz.au wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes: >About a month ago, some kind person sent me a text file that described >the circuit needed to create a MIDI interface for the BoudBlaster sound >card. If you can send it to me again, or if anyone else can help me >out, I promise that I won't lose it again.... :) I have just completed a MIDI interface for a soundblaster compatible card - Sound Galaxy BX. It uses the same pin outs as the soundblaster and it all seems to work. here is a rough diagram of the circuit I used. It is based on an article in the soundblaster newsletter, and some other MIDI interface circuits for other systems. 15 pin D connector 220R 1 +5v ------------------------/\/\/\---------------\ \ 4 5 gnd ---------------------------------------------2 MIDI OUT / 5 12 tx ------------------------/\/\/\---------------/ 220R 1 +5v --------------- | | \ | 220R / | R1 \ | / | | | 220R 15 rx -------- | ---------/\/\/\--------\ |C |B |A | \ 4 --------------------- | MIDI IN | 6 8 2 | ----- / 5 | | / \ IN914 --/ | PC900 | --- | | | | | | 5 3 | | | --------------------- | | |E |K | | | | | | 5 gnd -------- ---------------------- PC900 is a high speed optoisolator I built it on a small piece of veroboard in a small plastic box with the 2 MIDI 5pin DIN plugs mounted on the lid. You may want to check R1 above. In one circuit I saw it was a higher value (390R). I used 220R but I haven't looked at the output on a cro to check what the signal looks like yet. I tested it using my synth and it played ok and I was able to record ok. Let me know if you have problems. Could some kind soul who has a real midi interface confirm the value of R1 above? -- Rex Foord PC Support | Information Systems Division |"Time is nature's Email: rjf@gdwb.OZ.AU | Geelong & District Water Board | way of making sure Phone: +61 52 262329 | 61-67 Ryrie St Geelong | everything doesn't Fax: +61 52 218236 | Victoria 3220 Australia | happen all at once" | | W. Allen From: d92-lpe@sham69.nada.kth.se (Lars Persson) Newsgroups: comp.sys.ibm.pc.soundcard.tech Subject: Re: Schematics for SB MIDI Date: 24 Nov 1994 09:33:22 GMT Lines: 67 Message-ID: <3b1ml2$2q0@news.kth.se> References: <3b1i23$24v@news.kth.se> NNTP-Posting-Host: sham69.nada.kth.se Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit I just discovered that my correction of the SB MIDI Adaptor needs some correction! Below is an exact description of the adaptor I built yesterday, and it worked OK. MIDI IN: +-----------> To pin 5 of 15 pin conn. | To pin 9 of <------+ | +---------+----> To pin 15 of 15 pin conn. 15 pin connector | | | | |6 |5 |4 / v v v v v v v v v v +---------------+ \ <- 220 ohm resistor +-------------------+ | Sharp PC900 | / |Also, connect pin | | | | |2 of the MIDI conn.| | | +------> To pin 6 of PC900 |to pin 5 of the 15 | +---------------+ |pin connector. | |1 |2 |3 +-------------------+ | | | ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ \ | +-----> No connection 220 ohm resistor -> / | \ +------> TO pin 5 of MIDI connector | To pin 4 of <------+ MIDI connector MIDI OUT: 220 ohm resistors To pin 12 of 15 pin conn. <---------/\/\/\/\/---------> To pin 5 of MIDI conn. To pin 9 of 15 pin conn. <---------/\/\/\/\/---------> To pin 4 of MIDI conn. +----------------------------------------------------------------------+ | Do the same pin 2 of MIDI conn. to pin 5 of 15 pin conn. connection. | +----------------------------------------------------------------------+ For the 15 pin connector, it might be worth noticing that: pin 9 = pin 8 = pin 1 pin 5 = pin 4 I have used cables about 2 meters each, and it seems to be working. The cables are shielded, but I haven't connected the shields anywhere, so I guess unshielded cables will do just fine! Even though this works for me, you do this at your own risk! But I think it's hard to destroy any equipment with these low-voltage, low-current constructions. Even better luck, Lars Persson ** CS Student at the Royal Inst. of Technology, Stockholm, Sweden ** From: iscott@sempco.uucp (Ian Scott) Message-ID: Newsgroups: comp.sys.ibm.pc.soundcard.tech Subject: Corrected MIDI circuit! Date: 24 Nov 94 11:02:13 CDT Organization: Sim's Electronic Musicians' Publishing Company Lines: 91 To: iscott@sempco.uucp Subject: Re: Schematics for SB MIDI Newsgroups: comp.sys.ibm.pc.soundcard.tech In-Reply-To: Organization: Bartal Design Group, Inc. Cc: Hi-- In article you write: > >Here is a simple MIDI circuit for the standard 15-pin midi interface found >on most soundcards. The circuits that I've found have been a lot more >complex than this. Hypothetically, this circuit should be easier to build >than the more complex ones. If there is any reason whatsoever as to why this >shouldn't work, tell me!! > >This plan was originally made by Ronald Davis. I found it in an 'old' >issure of the Sound Blaster Digest. Any errors, please let me know. > >This is the MIDI IN circuit. >vvvvvvvvvvvvvvvvvvvvvvvvvvvv > > +-----------> To pin 5 of 15 pin conn. > | > To pin 15 of <------+ | +---------+------> To pin 9 of 15 pin conn. > 15 pin connector | | | | > |6 |5 |4 / > v v v v v v v v v v +---------------+ \ <- 220 ohm resistor >+-------------------+ | Sharp PC900 | / >|Also, connect pin | | or | | >|2 of the MIDI conn.| | HP 6N138 | +------> To pin 6 of PC900/6N138 >|to pin 5 of the 15 | +---------------+ >|pin connector. | |1 |2 |3 >+-------------------+ | | | > ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ \ | +-----> No connection > 220 ohm resistor -> / | > \ +------> TO pin 5 of MIDI connector > | > To pin 4 of <------+ > MIDI connector The diagram is close for a Sharp PC900; pins 4 and 6 seem to be reversed. The HP 6N138, according to my data book, is pinned totally differently. Also, pin 2 of the MIDI-IN connector should *not* be connected to pin 5 of the 15 pin, which is ground. Could cause a ground loop if connected. A 1N4148 (or equiv.) diode is usually connected across the opto-coupler's input, cathode to anode of the LED, anode to cathode of the LED. It prevents damage to the LED input from accidental high reverse voltage (static discharge, for example). >-=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- -=- > >This is the MIDI OUT circuit. >vvvvvvvvvvvvvvvvvvvvvvvvvvvvv > > 220 ohm resistor >To pin 12 of 15 pin conn. <---------/\/\/\/\/---------> To pin 5 of MIDI conn. >To pin 15 of 15 pin conn. <---------------------------> To pin 4 of MIDI conn. > >+----------------------------------------------------------------------+ >| Do the same pin 2 of MIDI conn. to pin 5 of 15 pin conn. connection. | >+----------------------------------------------------------------------+ This may or may not work with some cards. It depends whether or not the card's output can properly drive the current loop directly. A TTL buffer chip is usually used between pin 12 of the 15 pin connector and the 220 ohm resistor. And, yes, *here* is where to make the ground connection to pin 2. >Sorry, no MIDI THRU circuit. > > >This thing has been tested by the original creator of the circuit, so, it it >doesn't work, don't blame ME! I won't blame you, but I suggest that you correct your post before someone else does :-) . /-----------------------------------------/--------------------/ / -= Ian Scott =- Internet-ian@theden.com / Klingon son, you / / Internet-sempco!iscott@wupost.wustl.edu / killed my bastard! / / UUCP-wupost.wustl.edu!sempco!iscott / -unknown / /-----------------------------------------/--------------------/