Tascam FW1884 to MidiBox

[normen]

Hi,

I have a Tascam FW 1884 DAW Controller with two FE-8 Extenders for which there is no driver support anymore (the device uses FireWire). As I mainly use the control surface I want to build a MidiBox core into it to continue using it.

I have built a MidiBox remote before and just love the platform.

First I thought about using the new Motorfader core and a PIC Core per 8 faders but when looking into the boxes the PCB's are so nicely accessible and separately wired I thought it might be possible to reuse the motorfader circuitry. Luckily I have the service manual and layout of the device but sadly I'm not very savvy in these things.. I found out theres some 10bit A/D's working on the PCB, maybe theres a way to make a MIOS PIC talk to that? Or maybe with the new platform?

Here is some screenshots of the layout, it also contains the IC numbers, I wouldn't want to upload the whole service manual but tell me if you need to see other areas to tell me more.

This should be the touch and input stage I guess

And this is the motor driver chip it seems

There is not much more on the fader PCB so this is the data bus / PWM signal the PIC would have to work with.. If it can?

I'd be happy about any hints, maybe I don't have to rip out the whole fader PCB (to which the faders are soldered :/ ) then it would be a totally clean heart transplant so to speak.

Cheers and keep on MidiBoxing everybody :D

Normen

Edited July 18, 2012 by normen

[normen]

As a small update to the thread (I'll post everything about this endeavor here), I found out that Ploytec (the comany that does the GM5 midi chip) also does a USB 2.0 Audio board that should allow me to revive the audio part of the Tascam FW1884 interface as well!

Its a 16in/8out USB audio interface and the analog input section of the Tascam is just about the ideal companion to this board. As with everything in the FW-1884 the analog input and output sections are nicely separated and deliver exactly what this board needs via a ribbon cable. This should allow me to just throw in this board and have a full 8 mic-pre 8 line-out interface (maybe I can even make the ADAT part work some time).

On a sidenote, the GM5 midi evaluation board from ploytec is also just about ideal for the FW1884 as the GM5 needs optocouplers and midi ports for the additional 4 ports that are not on the board. Guess what, the FW1884 has 4 midi inputs and outputs and the board contains all necessary optocouplers and circuitry so I again only have to take a ribbon cable and connect it. :D

Sometimes the world can be so nice, I am getting suspicious here ;)

Cheers,

Normen

Edited April 13, 2012 by normen

[ilmenator]

I am not sure if the clean layout of the original hardware alone really justifies the effort of adapting MIOS to work with the components on the original board. I do not have a lot of experience with motorized faders, but from what I have seen in the schematics a drop-in replacement would probably mean that you provide analog inputs to read the fader positions, digital inputs for the touch sensors, and analog outputs for the motor control voltages (CV). All that sounds like far more effort than simply using one or two MF_NG modules.

Also, you would have to do some coding to get the system running - but you would not benefit from any updates TK would provide (think bugfixes or added functionality), because you would have a one-off custom solution.

If it is difficult to mount the faders properly without the original board, there is always the possibility to cut traces on the original board.

Best, ilmenator

[normen]

I am not sure if the clean layout of the original hardware alone really justifies the effort of adapting MIOS to work with the components on the original board. [..] All that sounds like far more effort than simply using one or two MF_NG modules. [..]

Thank you very much for the answer!

As I'll probably aim at simulating the Tascam Protocol as opposed to the Mackie Control Protocol I am already down to creating a separate application.. I guess I'll have to put some work into understanding the MF_NG module but from what you say I take it this would require the whole MIOS base to be adapted? Or are you talking about "normal" AIN AOUT modules here? I don't even know how similar (or different) the shift registers used by MIOS and the AD on this board work.. (why the heck do they convert the touch signals there already?)

I still think a drop-in replacement board would be very interesting as Tascam stopped support for this product and a similar one (US-2400) and I guess these will make great MidiBoxes when they pop up on ebay.. Maybe the app could even support the calibration protocol of the MIOS Studio MF_NG app. But as said, I am a noob in this respect and have to research a lot when I'm doing this kind of stuff so if you just told me "forget about it, makes no sense to think about it" in a nice way then I guess I'll have to live with that :)

Update on the USB Audio mod

The microphone and Line input circuitry with phantom power etc is in a separate block at the back of the device like I said before. Though now I saw that most of the analog preamp circuitry before the A/D is indeed on the main board of the Tascam FW1884 which I intend to remove from the device. This means I'll have to design a board with that input circuitry which gives me a chance to improve a bit on the used NJM4580 Op-Amps (maybe I'll use some OPA2604s). Luckily analog audio circuitry is something I don't have too much problems with ;)

Cheers,

Normen

[ilmenator]

...so if you just told me "forget about it, makes no sense to think about it" in a nice way then I guess I'll have to live with that :)

Well, as always in DIY: your mileage may vary :flowers:.

Creating your own board to mount the faders onto will be quite costly, as the board is going to be large. Also, I would assume that the one in the main unit looks different from the one in the extender units. So that will be two different design then?

[normen]

So that will be two different design then?

Yeah, for the main unit I'll also need two motorfader boards (I think?) as it sports a master fader in addition to the other 8 faders. The layout of the boards (FE-8 vs FW-1884) is very very similar though, the master fader is basically its own small circuit and the rest of the board is 1:1 the same as the one of the FE-8 (of which I have opened one to get further insight / start measuring and experimenting). I was thinking about using the new MIOS core for the main unit especially as now I also plan to integrate an audio board, I suppose the headroom and connectivity of the new platform will provide useful one way or the other.

For now I planned one PIC Core with a few DINX and DOUTX (some buttons are laid out as matrices, still gotta check how exactly I use that with the LC emulation) and one MF_NG module per device (or two for the master), then a GM-5 USB midi in the main unit. As I said, the 4 additional MIDI in/outs with optocouplers are already in the main unit. This way I could connect the two FE-8 via MIDI to the main unit instead of FireWire (using the original MIDI connectors on the main unit) and go to the PC via the GM5 USB port. The Audio part would be a completely separate USB port, allowing to use the units audio and midi part with different computers even (which will be handy in my project studio).

[normen]

So.. after spreading the single purchases over a few months I now started to build a PIC Core and DINX/DOUTX module and ripped apart one FE-8.

I finally decided to desolder the faders and use MF_NG boards (which are still on their way, parts are there).

Without the main board and the fader board theres a lot of space in the FE-8 :)

This is the circuitry on the board above, basically a button and a LED matrix, the LED matrix has some inverting transistors on the columns that make it unnecessary to keep high voltage on the inactive rows.

For the application, I was poking the assembler code for the LC and the button matrix with a stick for some weeks but as getting to a state where I would be able to fluently read and write assembler code would take a month or so I decided to do the button and LED matrix in C. I also got the PIC with the largest program memory, guess that will be handy as a C-based programmer ;) The MIOS C API really is nice, I never worked with it before, only hacked around in assembler projects.

So then it only took me some hours after I had the general workings of the FE-8 matrix worked out. The DINX module is driven +5V=on and the matrix works basically the other way round as the matrix in the MIOS blm examples. Modified the DINX module to support that and created a board where I can plug the DINX and DOUTX module onto female pin connectors. Since the pin rows of the DINX are "blocked" by the resistors I simply pushed the pin rows through to the bottom and soldered them there.

Now I can attach the two boards to the main board and replace/reuse them if needed. The purpose of this is to connect the modules to the 17-pin connector for the FE-8 matrix (the cable mess is below, I will probably etch a PCB for that when this prototype is working)

What shall I say.. It works! :D Basically I just keep bitmasks of the registers for each row that is checked (the 8 rows are cycled in my case, theres up to 16 columns in the main unit) and in the Tick method I check which ones changed and send MIDI events accordingly. Works nicely w/o debouncing as it seems, even the encoders.

So now its only about getting the encoder values converted properly which I'll probably do in the tick method based on the note id thats currently reported. If anyone has a better idea (or existing code) for the encoder matrix (which is displayed in the pic above) hit me :D

Expect some more frequent updates from now on ;)

Thanks again TK for making all this possible.

Cheers,

Normen

Edited July 18, 2012 by normen

[normen]

Sooo.. The fader PCBs are there and I connected the faders of the test box and it WORKS :)

Now I only gotta clean up the I/O PCB. Not sure if I'll pursue the "stick on" board thing though, might be the DINX and DOUTX boards are best placed separately.

P.S.: I almost got a broken FW-1884 on eBay. I know the guy who sniped it away is reading this thread, I shall withhold the software and special wiring info ;P