Re: [M100] MIDI with the Model T
On Tue, Mar 10, 2020 at 3:21 PM Tom Wilson wrote: > On Tue, Mar 10, 2020 at 3:16 PM John R. Hogerhuis > wrote: > >> Other issue is powering Arduino. >> > > I don't see that as an issue at all. > There are always ways but portability is important. -- John.
Re: [M100] MIDI with the Model T
Yes, you could do it with a Teensy. The only issue is that the ready made MIDI shiields won't fit on a Teensy, since the Teensy is a different shape than Arduino. So you'd either need to figure out the pin assignment or roll your own I/O board. Tom Wilson wilso...@gmail.com (619)940-6311 K6ABZ On Tue, Mar 10, 2020 at 4:01 PM Hiraghm wrote: > Thanks for all the info! > > My PMA-5 does have the serial connector, but it's a mini-din and I have > no clue what its pinouts are. > > But even though I'd like to use the M100 with the PMA-5 portably, I'd > still like to be able to talk to my MT-32 from the M100. > > > I have a couple of Max232 TTL/9 pin adapters I got for Rasberry Pi > projects, so I guess I could adapt one of those. > > Pardon my Arduino ignorance, but could this connection be made using an > Adafruit Teensy? I've seen projects for connecting keyboards, such as > the M100's which use the Teensy. > > >
Re: [M100] MIDI with the Model T
Thanks for all the info! My PMA-5 does have the serial connector, but it's a mini-din and I have no clue what its pinouts are. But even though I'd like to use the M100 with the PMA-5 portably, I'd still like to be able to talk to my MT-32 from the M100. I have a couple of Max232 TTL/9 pin adapters I got for Rasberry Pi projects, so I guess I could adapt one of those. Pardon my Arduino ignorance, but could this connection be made using an Adafruit Teensy? I've seen projects for connecting keyboards, such as the M100's which use the Teensy.
Re: [M100] MIDI with the Model T
On Tue, Mar 10, 2020 at 3:16 PM John R. Hogerhuis wrote: > Other issue is powering Arduino. > I don't see that as an issue at all. It uses its own power supply, just like the synthesizer will. You can power an Arduino from a 9v wall wart or a USB power supply. If this needs to be portable, a USB power pack works great (although you may have to add some LEDs to keep the load high enough to keep the pack running.)
Re: [M100] MIDI with the Model T
On Tue, Mar 10, 2020 at 1:34 PM Tom Wilson wrote: > > Google search (aside from Model T) says some devices are tolerant of 30720. >> Some devices can be switched to non-standard 38400bps which Model T is >> exactly capable of. >> Also I wonder if there are confounding variables like flow control, and >> wiring? >> -- John. > > > There shouldn't be any issues with flow control: MIDI is about the > simplest serial interface there is: it's a 2-wire current loop. The > specification calls for 1% tolerance, so the most you can vary is 312.5bps. > That makes a maximum of 31,562.5 and a minimum of 30937.5. So 30720 is out > of spec. Devices like the Sound Canvas and Yamaha XG synths can accept data > on the serial port at 38,400, but that's a special case and based on the > firmware of the device setting its internal UART to that speed. > > Yes, I agree it's out of spec. How often it works is a different question. " Devices like the Sound Canvas and Yamaha XG synths can accept data on the serial port at 38,400, but that's a special case and based on the firmware of the device setting its internal UART to that speed. " Right. That's what I understood. Some devices specifically have a (non-standard) feature of being able to operate at 38,400 > I've been thinking about this, and what I'd probably do is use an Arduino > as a translator. You can connect the T-100 to an Arduino through a serial > connection using a simple MAX232 level converter, or your can use the > parallel port to send 8 bits at a time. From there, you can use a MIDI > shield to connect to a synthesizer. You don't need a large program; it's > basically just relaying data with a small amount of buffering. So even an > Uno can do the job. > Parallel port sounds like a good way. Who's going to be running their dot matrix and playing MIDI files simultaneously? Other issue is powering Arduino. -- John. >
Re: [M100] MIDI with the Model T
> Google search (aside from Model T) says some devices are tolerant of 30720. > Some devices can be switched to non-standard 38400bps which Model T is > exactly capable of. > Also I wonder if there are confounding variables like flow control, and > wiring? > -- John. There shouldn't be any issues with flow control: MIDI is about the simplest serial interface there is: it's a 2-wire current loop. The specification calls for 1% tolerance, so the most you can vary is 312.5bps. That makes a maximum of 31,562.5 and a minimum of 30937.5. So 30720 is out of spec. Devices like the Sound Canvas and Yamaha XG synths can accept data on the serial port at 38,400, but that's a special case and based on the firmware of the device setting its internal UART to that speed. I've been thinking about this, and what I'd probably do is use an Arduino as a translator. You can connect the T-100 to an Arduino through a serial connection using a simple MAX232 level converter, or your can use the parallel port to send 8 bits at a time. From there, you can use a MIDI shield to connect to a synthesizer. You don't need a large program; it's basically just relaying data with a small amount of buffering. So even an Uno can do the job. Here's another summary I found: http://www.personal.kent.edu/~sbirch/Music_Production/MP-II/MIDI/midi_physical_layer.htm Although note that his cabling diagram is wrong. MIDI cables should only have the shield connected at one end. Never connect the grounds of two audio devices together through the MIDI cable, as this causes ground loops and hum. So properly designed MIDI cables (as opposed to generic DIN-5 patch cables or PC keyboard extensions) only connect the shield at one end. Tom Wilson wilso...@gmail.com (619)940-6311 K6ABZ
Re: [M100] MIDI with the Model T
On Tue, Mar 10, 2020 at 8:54 AM Mike Stein wrote: > We had a discussion about MIDI a few years ago and it was feasible; there > was a fairly simple interface and some proof of concept software but I > don't recall any actual serious software. > > Possibly some MIDI devices are more particular about baud rate than others > but it worked with my keyboards at the time. > > I wonder if that discussion can still be found in the archive... > > Google search (aside from Model T) says some devices are tolerant of 30720. Some devices can be switched to non-standard 38400bps which Model T is exactly capable of. Also I wonder if there are confounding variables like flow control, and wiring? -- John.
Re: [M100] MIDI with the Model T
We had a discussion about MIDI a few years ago and it was feasible; there was a fairly simple interface and some proof of concept software but I don't recall any actual serious software. Possibly some MIDI devices are more particular about baud rate than others but it worked with my keyboards at the time. I wonder if that discussion can still be found in the archive... m - Original Message - From: Alex ... To: m...@bitchin100.com Sent: Monday, March 09, 2020 10:00 AM Subject: Re: [M100] MIDI with the Model T Yeah I was using the OUT keyword to do like you just said. That baud rate wasn't close enough for my synthesizers to understand it. On Sun, Mar 8, 2020, 18:39 John R. Hogerhuis wrote: If 30720 isn't close enough, you might be able to do it with dedicated code in software (bitbang). But you'll need to use some other I/O pins and and a level shifter. Steve was doing something like this with the cassette port. A third way would be to find a UART that is capable of the baud 31250 and interface it to the bus. -- John.
Re: [M100] MIDI with the Model T
Yeah I was using the OUT keyword to do like you just said. That baud rate wasn't close enough for my synthesizers to understand it. On Sun, Mar 8, 2020, 18:39 John R. Hogerhuis wrote: > If 30720 isn't close enough, you might be able to do it with dedicated > code in software (bitbang). But you'll need to use some other I/O pins and > and a level shifter. Steve was doing something like this with the cassette > port. > > A third way would be to find a UART that is capable of the baud 31250 and > interface it to the bus. > > -- John. >
Re: [M100] MIDI with the Model T
Tom Wilson wrote: > Some other devices, such as certain models of Sound Canvas and a > few varieties of Yamaha XG sound models actually have a serial port > interface built right into the machine. So you could send MIDI data to > one of those without needing the level conversion. > > The only issue is that I'm not sure if or how the serial port can be set > to the correct baud rate. MIDI runs at 31250 bps. I'm not sure how the > T100's UART is programmed at the machine level, so that could be a > concern. Not sure about the MT-32 or other models but I own a Roland SC-88 and there is a switch on the back of the unit allowing to chose between 31250 and 38400 bps. Note that the serial connector is a mini-din and you will need a specific cable, but Roland was kind enough to give the cable's wiring diagram in the SC-88 owner's manual Hiraghm wrote: > I've been reading recent threads about someone using the cassette > interface as a secondary display interface. I suppose maybe that > could be used, instead, too... The Roland serial cable uses handshake signals so you may need to simulate that to know when the MT-32 is ready to receive the next midi frame, as the cassette interface hack only gives you one TX line (unless I missed something :o) ). > So is this idea crazy? Impossible? Waste of time? As long as you're having fun figuring it out, that's never a waste of time ;o) Eric
Re: [M100] MIDI with the Model T
If 30720 isn't close enough, you might be able to do it with dedicated code in software (bitbang). But you'll need to use some other I/O pins and and a level shifter. Steve was doing something like this with the cassette port. A third way would be to find a UART that is capable of the baud 31250 and interface it to the bus. -- John.
Re: [M100] MIDI with the Model T
On Sat, Mar 7, 2020 at 6:14 PM Alex ... wrote: > I tried doing this with my T102 a few years back and couldn't get the baud > rate anywhere close to 31250. > >> >>> What did you try? You need to set the baud rate divisor directly. You cannot use the BASIC port OPEN string or TELCOM to set the speed. Open the port first, then override with OUT commands or ML code. http://bitchin100.com/wiki/index.php?title=Model_100_Serial_Interface I guess the divisor you want to program is 153600 / 31250 = 4.9152 Closes integer divisor is therefore 5. So, Port $BD = 64 Port $BC = 5 Another way of looking at is, the closest you can get is 30720bps. I don't know if that's close enough for compatibility. -- John.
Re: [M100] MIDI with the Model T
I tried doing this with my T102 a few years back and couldn't get the baud rate anywhere close to 31250. On Sat, Mar 7, 2020, 20:34 Tom Wilson wrote: > Serial to MIDI adapters are around - although you'd probably have better > luck finding a design and building one yourself than finding a pre-made > one. (The serial port being the wrong gender doesn't help things.) > > The protocol itself is largely the same, but you need level conversion, > and the baud rate is 31250bps. Not all UARTs can be programmed for that > speed, so that's something TBD. > > Here's a circuit. It looks like it uses a MAX232 for level shifting and a > 6N138 on the input side to make the current loop usable by the MAX. > > If you're just looking to transmit, you can skip the 6N138 and just use > the MAX232 and associated support bits (caps and resistors.) > > Some other devices, such as certain models of Sound Canvas and a few > varieties of Yamaha XG sound models actually have a serial port interface > built right into the machine. So you could send MIDI data to one of those > without needing the level conversion. > > The only issue is that I'm not sure if or how the serial port can be set > to the correct baud rate. MIDI runs at 31250 bps. I'm not sure how the > T100's UART is programmed at the machine level, so that could be a concern. > > One way around this might be to use an Arduino as a buffer - connect the > Arduino and the computer with a simple MAX232 converter, then use the > Arduino to send the actual MIDI messages through a MIDI shield. (Or just > get the musical instrument shield with the on-board synth.) > > > > > > > > > Tom Wilson > wilso...@gmail.com > (619)940-6311 > K6ABZ > > > On Sat, Mar 7, 2020 at 4:38 PM Hiraghm wrote: > >> I vaguely recall a few months back someone talking about some kind of >> MIDI with their M100. >> >> I've got a Roland MT-32 and a couple PMA-5s, and I got to wondering how >> I could interface them to my M100, then maybe write some MIDI >> player/editor software. >> >> Just saw a video tutorial on YouTube where Bisqwit wrote a MIDI player >> program for DOS in GW-BASIC. >> >> A serial port interface, assuming one could be built, would be fast >> enough; iirc MIDI communicates at the same speed as HTerm. >> >> A parallel port interface might be more convenient, if possible... >> >> I've been reading recent threads about someone using the cassette >> interface as a secondary display interface. I suppose maybe that could >> be used, instead, too... >> >> Now I'm wondering if a MIDI keyboard could be interfaced via the bar >> code reader port? >> >> If so... PMA-5 connected via serial, parallel or cassette port, MIDI >> keyboard connected via barcode port, custom software... portable MIDI >> DAW... >> >> So is this idea crazy? Impossible? Waste of time? >> >>
Re: [M100] MIDI with the Model T
Serial to MIDI adapters are around - although you'd probably have better luck finding a design and building one yourself than finding a pre-made one. (The serial port being the wrong gender doesn't help things.) The protocol itself is largely the same, but you need level conversion, and the baud rate is 31250bps. Not all UARTs can be programmed for that speed, so that's something TBD. Here's a circuit. It looks like it uses a MAX232 for level shifting and a 6N138 on the input side to make the current loop usable by the MAX. If you're just looking to transmit, you can skip the 6N138 and just use the MAX232 and associated support bits (caps and resistors.) Some other devices, such as certain models of Sound Canvas and a few varieties of Yamaha XG sound models actually have a serial port interface built right into the machine. So you could send MIDI data to one of those without needing the level conversion. The only issue is that I'm not sure if or how the serial port can be set to the correct baud rate. MIDI runs at 31250 bps. I'm not sure how the T100's UART is programmed at the machine level, so that could be a concern. One way around this might be to use an Arduino as a buffer - connect the Arduino and the computer with a simple MAX232 converter, then use the Arduino to send the actual MIDI messages through a MIDI shield. (Or just get the musical instrument shield with the on-board synth.) Tom Wilson wilso...@gmail.com (619)940-6311 K6ABZ On Sat, Mar 7, 2020 at 4:38 PM Hiraghm wrote: > I vaguely recall a few months back someone talking about some kind of > MIDI with their M100. > > I've got a Roland MT-32 and a couple PMA-5s, and I got to wondering how > I could interface them to my M100, then maybe write some MIDI > player/editor software. > > Just saw a video tutorial on YouTube where Bisqwit wrote a MIDI player > program for DOS in GW-BASIC. > > A serial port interface, assuming one could be built, would be fast > enough; iirc MIDI communicates at the same speed as HTerm. > > A parallel port interface might be more convenient, if possible... > > I've been reading recent threads about someone using the cassette > interface as a secondary display interface. I suppose maybe that could > be used, instead, too... > > Now I'm wondering if a MIDI keyboard could be interfaced via the bar > code reader port? > > If so... PMA-5 connected via serial, parallel or cassette port, MIDI > keyboard connected via barcode port, custom software... portable MIDI > DAW... > > So is this idea crazy? Impossible? Waste of time? > >
