13 replies to this topic

[Kvetch]

Hi folks. I have decided to add a midi merger to my midibox project.

Currently my Midibox consists of 2 core modules that do not have LCD screens, and are used as midi filters and processors that alter the signals going between my Shruthi-1, my EMX and my ESX.

I figured because they have no LCD screen I could power the merger from the same power source. So I connected up the J2 output of the core to J4 on my merger kit form Mikes Site, plugged MIDI out of my interface to MIDI in 1 on the merger, and MIDI In of my interface into the Out on the merger. Im just getting 'No response from core' message in MIOS Studio 2.2

Ive also tried using MIDI In 2 on the merger instead of In 1, but same thing. Im a bit confused in general about what voltages should read on the merger, and also the pics of the merger show all different orientations for caps.



That merger pic shows the capacitor at the top left with its negative stripe pointing up towards the edge of the PCB, but then the images inside midimerger_pcb_v1.zip show the opposite.

Im rather confused in general with the midimerger project

[Kvetch]

Also am I correct in thinking with the above circuit the power has to come from J2 on a core and cant come direct from the DC input jack?

[nILS]

You can power the board via J1 with AC/DC (J1 goes to the rectifier, then to the 7805, ie the merger has a full PSU section).

So I connected up the J2 output of the core to J4 on my merger kit form Mikes Site

J2 of the core needs to be connected with J2 of the merger board. Since the merger doesn't really have any other port, I assume that's a typo? Semi-edit: I just noticed it's actually called JP4 in Mike's layout... Your caps are correctly aligned (at least they match with the pcb layout).

The voltages on the merger should be essentially the same as on the PIC18F core module.

What are you trying to do atm? Upload the merger app? Is the bootloader preburned on the PIC? If not, you'll need to burn the hex file, not upload it. Do you have another core that you could check the PIC in? Do you get upload requests from the PIC in MIOS Studio?

[Kvetch]

I requested that the bootloader be burned on the chip when I bought from Mikes store so I assume its on there. But MIOS studio doesnt recognise the core at all. Ill try swapping PICs with my working core module when I get home tonight and see what happens. Thanks for the suggestion, Ill keep you posted

[Kvetch]

OK heres an update:

When I measure the VDD I get exactly 5V at all points I should except the one Ive boxed in blue:





I dont know if the merger from Mikes site is supposed to have 5V at that point as the above image is just general core measurements, but Ive resoldered the joint in question and its just 0.0V.

Also I took the PIC out of the merger and put it in my working core and still get 'no response from mbhp core' in MIOS Studio. So I presume this means that if the above joint is not supposed to be 5V then its because my bootloader isnt burned. If this is the case how would I go about getting it burned as I know nothing about this process. I requested a bootloader to be loaded when ordering from Mike.

Thanks in advance!

[Kvetch]

Another update. Mike has emailed me back and confirmed he definitely burned the bootloader onto the PIC, so now Im really confused, as when I put it into my working core I dont get the 'bootloader is up and running' message. So confused....lol

[Kvetch]

Another update again. Big thanks to Mike for his quick responses to me by email. He has confirmed with me my PIC I ordered for the merger was burned with 'midimerger_pic18f_with_bootloader.hex'

This would explain why MIOS Studio doesnt really see the core, but I still dont have a working merger and dont understand why. I get the correct voltages in the correct places. I just dont get it.

Im totally stuck on this one :(

[nILS]

Okay, if the firmware is good and the voltages are good, typically your best bet would be the optocouplers. Replace one of them with a known good one from a working core and see if you can get a loopback test to work (PC Out -> merger in, merger out -> pc in, play some notes in MIOS Studio, they should show up in the input monitor).

[Kvetch]

Thanks again nILS, Ill try your suggestion soon as I get home tonight and report back. Im sure I must be very close to getting a working merger here.

[Kvetch]

Finally got the chance to try this out and loopback works fine! Basically it seems like every test I do points to the core being working fine, yet it wont actually do as its supposed to in the end.

[nILS]

Um... The loopback working actually does mean the merger is doing just what it's supposed to do: It takes the incoming MIDI (from 2 inputs) and outputs it to the MIDI out... I don't quite see what the problem is here

[Kvetch]

Im as confused as you nILS, basically all tests work fine, but when I plug a single MIDI source or pair of MIDI sources into the inputs, I get nothing from the output.

[TK.]

Hope that you won't hate me for this obvious question, but just to ensure: you've to connect the MIDI OUT of your MIDI source to a MIDI IN of the merger, did you consider this?

Best Regards, Thorsten.

[nILS]

but when I plug a single MIDI source or pair of MIDI sources into the inputs

Wait, what? You just said the loopback works. Which means it's working. Stuff from the merger's MIDI in is forwarded to the merger's MIDI out.

Did you actually do this?

PC MIDI out >-------------------> Merger MIDI in (1 or 2)
PC MIDI in <-------------------< Merger MIDI out

Connect the midi device in MIOS Studio

Play notes in MIOS Studio on the cute little keyboard window.

Watch the notes show up in the MIDI In Monitor in MIOS Studio.