Jump to content

GM5: Least-cost USB-MIDI Interface Chip for 4.50 EUR


TK.

Recommended Posts

  • Replies 732
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

I've often wondered, when you use a USB / MIDI chip like this, is it possible to get it talking to your PIC more efficiently than MIDI itself?  For example, could you build an IIC USB module that can act like multiple MIDI "cables"?  Can it communicate with a PIC at a faster-than-MIDI speed, which could allow for better timing?

Link to comment
Share on other sites

I've often wondered, when you use a USB / MIDI chip like this, is it possible to get it talking to your PIC more efficiently than MIDI itself?  For example, could you build an IIC USB module that can act like multiple MIDI "cables"?  Can it communicate with a PIC at a faster-than-MIDI speed, which could allow for better timing?

In theory yes. In practice it can affect the architecture of the firmware. E.g., required MIDI In/Out buffer size, maximum allowed CPU load, interrupt priorities, etc...

MIOS and most main applications have been designed for MIDI baudrate. Using higher baudrates can lead to failures.

Best Regards, Thorsten.

Link to comment
Share on other sites

since there are many avr with usb, why the monome creators used a ftdi chip?

did tk ever cosidered to implement those chips in mbhp?

regarding gm5: did the creators write dedicated driver? is there a  standard tool like ez-usb for cypress?

what happens if i connect two gm5 to a computer?

and what happens in i try to connect two (or more) usb modules (cypress based) to a single computer?

i'm curios about the case in wich i build many usb midiboxes and i intend to use all these with a single computer...

Link to comment
Share on other sites

since there are many avr with usb, why the monome creators used a fdti chip?

Just ask them, and please let me know about the reasons.

did tk ever cosidered to implement those chips in mbhp?

Yes, TK has considered this several times. There are at least three reasons why I don't find them suitable for MBHP:

- SSOP package, you are not able to solder this with a soldering iron

- expensive (because you need an additional adapter board SSOP->DIP (or similar) format)

- MIDI protocol not natively supported, a proxy is required which makes the usage complicated and error prone whenever you upgrade to an operating system which isn't supported by the proxy

regarding gm5: did the creators write dedicated driver?

Both: standard USB-MIDI and dedicated driver for windows (which hopefully fixes the known flaws which are documented at my website - I will test this)

is there a   standard tool like ez-usb for cypress?

You don't need a programmer, the closed-source firmware is already programmed into the chip.

what happens if i connect two gm5 to a computer?

We will see... ;)

As mentioned in my initial posting, I won't order the first batch before I tested the chip under Windows and MacOS

and what happens in i try to connect two (or more) usb modules (cypress based) to a single computer?

i'm curios about the case in wich i build many usb midiboxes and i intend to use all these with a single computer...

You will see multiple devices - the max configuration I ever tested was 3 MBHP_USB and 1 MBHP_USB_PIC module.

I guess, that for the GM5 chips it will work the same way...

Best Regards, Thorsten.

Link to comment
Share on other sites

You will see multiple devices - the max configuration I ever tested was 3 MBHP_USB and 1 MBHP_USB_PIC module.

I guess, that for the GM5 chips it will work the same way...

Best Regards, Thorsten.

mmmhh... so there is no need to modify the driver, in cubase\nuendo i'll se many midi ports as many usb modules i connect to the pc. right?

i just plug a second module and it will be recognized..

regarding the general concept: if i actually build a midibox with usb it's like building two machines in one: a midi-usb interface and a classic midibox controller.

in the monome project (if i understand) midi (or osc) data is generated by a software (the driver that recives serial signals from the hardware device)

this solution transfers "complexity" from the mcu to the driver.

don't you think that all the pic-usb problems could be solved using such a configuration? so there re no midi issues at all before the driver

anyway i'll join monome forum to get more infos

Link to comment
Share on other sites

this solution transfers "complexity" from the mcu to the driver.

don't you think that all the pic-usb problems could be solved using such a configuration? so there re no midi issues at all before the driver

The big plus of the GM5 solution is that we finally have the chance to get an industy quality custom driver for a cheap USB-MIDI chip. If the "complexity" was transferred into the driver, this would mean we couldn't use this driver and a custom driver had to be made. A good driver is exactly the thing that was missing for the previous Midibox-USB solutions, so willingly decide to not use the original GM5 driver would be one of the most stupid things to do.

I'm wondering what's your motivation to question and complicate concepts before it was even fully tried out and tested? Can't you just be happy that a good solution seems near, wait like everyone else and then decide if that solution is suitable for your needs?

S

Link to comment
Share on other sites

i was just curious, seppoman.

the questions i made regard general usb handling in diy projects, and are not strictly related to gm5 or to mios.

of course i'm happy about gm5 "as-is"

i only underlined that in a "monome like" solution you can freely handle midi, osc, qwerty or mouse control with less worry for mcu programming. i'm curious about the solutions in this direction

Link to comment
Share on other sites

OSC is cool, but my primary focus is on MIDI, therefore you won't find alternative solutions from my side. This doesn't mean, that a skilled programmer wouldn't be able to build other protocols into his MIDIbox firmware.

i only underlined that in a "monome like" solution you can freely handle midi, osc, qwerty or mouse control with less worry for mcu programming. i'm curious about the solutions in this direction

With MIDI, a MIDIbox can easily talk with any MIDI compatible device without firmware changes. For example, it doesn't matter if you control a MIDIbox SID directly from your MIDI keyboard, from your hardware sequencer, or from your computer. You can especially control it from all these devices the same time with the same protocol, and without baudrate adaptions.

Or a MIDIbox SEQ can not only send data to your computer, but to any MIDI device without firmware changes.

Today, OSC is still only useful in conjunction with computers. So, why not using a Proxy which converts MIDI into OSC instead of OSC (or any other plain serial stream) into MIDI? From the functional point of view, it's the same, you only need to find a clever MIDI event coding. Yes, OSC has also advantages, but just compare them with the possibilities already given by MIDI, and decide by yourself which advantages are stronger.

We could also say: it's a different philosophy. Example: go to youtube, and watch my stribe demo (keywords: "stribe ucapps"). Search for other stribe demos, and tell me, which solution is using MIDI as transfer protocol, and which one is using OSC. Do you see any function, which cannot be realized with MIDI?

As mentioned above, most firmwares have been tailored for MIDI baudrate. However, a generic device like a x*y button/LED matrix could also run with a much higher baudrate, but most MIDIbox firmwares are "a bit" more complex than a minimal  application like Monome... anyhow, it's the same: a skilled programmer should know, how to change the baudrate, and what it means for his application.

Btw.: do we really need to talk about such technical topics in a "bulk order" thread?

Best Regards, Thorsten.

Link to comment
Share on other sites

Per chip you will get one physical MIDI IO, and up to 5 virtual MIDI In/Out devices ("MIDI cables") to your operation system (which makes this solution multiclient capable). Number of "cables" can be configured, so you can also get only a single pair of MIDI cables if you prefer this.

Thorsten, i confess: i misunderstand something.

Please circle  correct answer(s):

option 1:

we get the full depicted interface, which is ready to fire, we only need to solder it together. (or it even comes prebuilt)

option 2: we get the chips (and...)

A) Do we get something else per chip too, or only bare chips with ?

B) You're going to build the circuit, effectively replacing existing one, and implementing it within MBHP.

option 2.1 we get ONLY the chips from ploytec, cables, but not the pcb.

Then, if so, is it possible within this batch to get from ploytec at least one of their standard USB-MIDI interface pcb, in addition to chips, like it appears on their homepage? I need it this interface for other uses too, rather than for MBHP exclusively.

thanks for patience, stay tuned!

:)

Vlad

Link to comment
Share on other sites

Hi Kartoshka,

Please circle  correct answer(s):

option 1:

we get the full depicted interface, which is ready to fire, we only need to solder it together. (or it even comes prebuilt)

option 2: we get the chips (and...)

A) Do we get something else per chip too, or only bare chips with ?

B) You're going to build the circuit, effectively replacing existing one, and implementing it within MBHP.

option 2.1 we get ONLY the chips from ploytec, cables, but not the pcb.

Then, if so, is it possible within this batch to get from ploytec at least one of their standard USB-MIDI interface pcb, in addition to chips, like it appears on their homepage? I need it this interface for other uses too, rather than for MBHP exclusively.

read this:

I'm planning to start a bulk order for "GM5" - this is an Atmel AVR based USB chip with preburned USB-MIDI firmware (out-of-the-box solution)

3.50 EUR pp. for a batch of 250 chips

Order won't be started before compliance check passed under Windows and MacOS, at least 250 chips are in the waiting list, and everybody has prepaid

Note that a MBHP PCB for this chip isn't available yet, I will create a layout once we got the first batch.

So, please add your name and the quantity of chips to this list

  -> http://www.midibox.org/dokuwiki/tk_gm5_bulkorder

What do you think you will get? ;)

S

Link to comment
Share on other sites

Btw.: do we really need to talk about such technical topics in a "bulk order" thread?

you're right. but i have a last question.

yoy sayd that ftdi chips are difficult to solder. but what is the difference with the fm chips or the cypress or the gm5 itself?

i saw the picture on the ploytec site and it seems that they use the smd version of the avr

or there is such an intermediate format?

Link to comment
Share on other sites

yoy sayd that ftdi chips are difficult to solder. but what is the difference with the fm chips or the cypress or the gm5 itself?

i saw the picture on the ploytec site and it seems that they use the smd version of the avr

or there is such an intermediate format?

SMD != SMD - there are differences between package formats and pin pitch...

To give you an impression:

this is the pitch which is good for DIY, and which can be expected for GM5:

smd_fine.jpg

And this is the pin pitch of a FTDI chip:

smd_bad.jpg

(sorry, but my camera had problems to zoom this properly ;))

Best Regards, Thorsten.

Link to comment
Share on other sites

Ok, after a phone call I got some very good news:

1) each GM5 chip provides 5 physical MIDI IO ports!

(means: 0.70 EUR per IO port - compare this with commercial interfaces! :))

2) an external EEPROM for storing the vendor ID won't be required - and we will get our own vendor/product ID

(I will use one of the IDs which have been sponsored by voti.nl)

3) the windows driver will be multi-client capable

No need for virtual cable/router workarounds

MacOS is multi client capable w/o additional driver

4) They consider to sell PCBs

More infos (especially about the prices) soon

Best Regards, Thorsten.

Link to comment
Share on other sites

Addendum: you are allowed to re-enter the quantity of chips you are planning to buy to give over people the possibility to join the first batch order. Please only take care, that the n x 250 pieces criteria is fullfilled

Best Regards, Thorsten.

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...