Trouble connecting IIC modules to CORE32 (MidiSeq v4)

MIDIbox SEQ
1

Hi there,

My MidiSeq V4 has 3 IIC modules connected to the core but none of them is responding (none of the lights are flashing).

I followed the MidiSeq V4 interconnections diagram but nothing happens. I put the 1k resistor between Vd and SC.

In the Midi Seq Menu, IIC1, IIC2, IIC3 and IIC4 appear with a * (meaning they cannot be recognized nor selected I guess).

Here is a picture of the 3 IIC modules, just in case :

One last thing, just to be sure : IIC modules on a CORE32 only provide MIDI OUT, right ? Does this mean that only the MIDI OUT plug of each module is usable ?

Thanks for your help!

IIC-modules.jpg
IIC-modules.jpg1024×768 355 KB

2

Only the OUTs work with the core32 running SeqV4.

The the green LED on each module should be lit when the power is applied. The red LED should flash with MIDI OUT.

Make sure the correct header (J4)on the core is used and that you have the wires the right way around.

3

J4 on the CORE is connected to J2 on the IIC modules. I checked voltage and the modules do receive a little more than +5v.

Any idea from here ?

(If midi IN on the IIC modules with CORE32 are not enabled, I think I’ll remove them to gain space… I mean, when they work OK !)

4

Hi!

Do you have programmed PIC’s in IIC modules?

>Yes, you can remove midi in sockets, and you can also remove optocouplers from

IIC modules.

Best regads, IGI

5

Thanks for the confirmation… but I have to make them IIC modules work first ! :hmm:

6

The green LED notifies that the module is correctly powered, and that the IIC_MIDI firmware is up & running.

A Ground/5V connection is already sufficient for this state.

Check the polarity of this LED (short leg: cathode)

If you don’t remember the length of the legs anymore, look into the LED: here the longer terminal is the cathode, the short one is anode.

See also following photo:

Best Regards, Thorsten.

mbhp_iic_midi_leds.jpg
mbhp_iic_midi_leds.jpg800×1006 138 KB

7

Solved !

Thank you (again) Thorsten. It was a combination of wrongly-soldered diodes (how could I do such a mistake!!!) and 1K resistor on STM32 J4 whereas apparently it is not needed with my STM32 revision. IIC1, 2 and 3 work great and I’m sooo happy to let go my external midi splitter…

Now I’m trying to find back the connection for MIDI OUT3 on STM32 (I read that… but where? :rolleyes: )

All the best, Gael

8

Midi out 3 is on the interconnections pdf here

You will need to use an opto coupler etc as midi out 3 is at TTL levels.

9

On the mbhp_core_stm32_midi3_extension.pdf file, it seems that only the MIDI IN 3 needs the 6N138 optocoupler…

I tried without the optocoupler using two 220ohm resistors and +5v from J2 with no ground but it doesn’t work… I’m gonna try with ground and see what happens !

10

IT WORKS !

You just have to solder the wires correctly… :whistle:

Thanks again Thorsten !