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Help with duo-color matrix mapping


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Hello there!

I want to build my version of a SEQ4+ and I am currently a bit stuck with the mapping of the LEDs.

Specifically, in the configuration file MBSEQ_HW.V4, there is a mapping variable BLM8X8_DOUT_GP_MAPPING. Can someone help me how to figure out, how those mappings are laid out?

I attached a spreadsheet with the configuration I have in mind (in italic the definitions I'm unsure if they make sense). I want to use BLM8X8_DOUT_GP_MAPPING = 3. Is it correct, that this configuration uses 2 SR for the LEDs in a Matrix configuration?

Cheers, stahl


Edited by stahl
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GP LEDs are (unfortunately) not free assignable, therefore BLM8X8_DOUT_GP_MAPPING has been introduced to consider different hardcoded options:

So, from documentation point of view, Option #1 is probably the most save solution because you can compare Wilba's schematic with yours.

The mapping is implemented in https://github.com/midibox/mios32/blob/master/apps/sequencers/midibox_seq_v4/core/seq_ui.c line #3579 (search for "seq_hwcfg_blm8x8.dout_gp_mapping == 1")

Best Regards, Thorsten.

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Thank you TK, looking at the code and config helped me to figure it out.

Matrix A LED mapping (BLM8X8_DOUT_GP_MAPPING 3)

	0	1	2	3	4	5	6	7
M2	GP1-R	GP1-G	GP2-R	GP2-G	GP3-R	GP3-G	GP4-R	GP4-G
M3	DT1-R*	DT1-G	DT2-R	DT2-G	DT3-R	DT3-G	DT4-R	DT4-G
M6	GP5-R	GP5-G	GP6-R	GP6-G	GP7-R	GP7-G	GP8-R	GP8-G
M7	DT5-R	DT5-G	DT6-R	DT6-G	DT7-R	DT7-G	DT8-R	DT8-G
* DT = DIRECT_TRACK (selection button leds)

I didn't test this yet, but it should be right.

Cheers, stahl

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It looks correct when I compare with the code, and actually it seems that the comment is wrong:

      // BLM_X DOUT -> GP LED mapping
      // left/right half offsets; green,red
      // 0 = 8,9        1 = 11,10       2 = 13,12       3 = 15,14
      // 4 = 40,41      2 = 43,42       3 = 45,44       4 = 47,46

should be:

      // BLM_X DOUT -> GP LED mapping
      // left/right half offsets; green,red
      // 0 = 9,8        1 = 11,10       2 = 13,12       3 = 15,14
      // 4 = 41,40      2 = 43,42       3 = 45,44       4 = 47,46

So, 0 and 4 follow the same "swapped order" like other Duo-coloured LEDs.

do you agree?

Some additional hints:

  • the relation between row M1..M8/column 0..7 and the 74HC595 output pins can be confusing - many people connected the pins in mirrored order in the past - be careful about that, otherwise the GP pin assignments have to be changed in the source code (-> you will need a local build).
    Wilbas schematic is a good reference in which order data lines have to be connected
  • 1st and 2nd color (typically "red" and "green") can be swapped during runtime in the Options page
  • for all other LEDs the assignment doesn't matter because they are free configurable in the MBSEQ_V4.HW file - you can try out once the front panel is working

Best Regards, Thorsten.

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