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latigid on

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  3. 8x24 LED matrix

    in MIDIbox NG

    Posted

    No problem, hope it's helpful!

    You will need to figure out the wiring puzzle. The following links might be of use:

    http://ucapps.de/midibox_ng_manual_ngc.html -> search "LED_MATRIX" and "DOUT_MATRIX"
    There you can understand how things will look in software.


    http://ucapps.de/mbhp/mbhp_dout_8x8leds.pdf
    http://ucapps.de/mbhp/mbhp_dout_8x16leds.pdf
    http://www.midibox.org/dokuwiki/lib/exe/fetch.php?media=home:users:ilmenator:rgb-led:midibox_rgb-led_matrix_8x8_v1.3_schematic.pdf
    https://github.com/midibox/mios32/blob/master/apps/controllers/midibox_ng_v1/cfg/tests/blm16x4.ngc

      

    DOUT_MATRIX n=1  rows=4  inverted=0  sr_dout_sel1=1  sr_dout_r1=2  sr_dout_g1=3

    This is an .NGC example of one four-row matrix. In theory you could share the same sr_dout_sel1=1, though you still need dedicated RGB columns. As you have common-anode LEDS: 

    inverted_sel=1 and (optionally) inverted_row=1

    commands should be used when defining the matrix.

     

    6 hours ago, doc.g4 said:

    create one larger matrix using sparks fun type shiftreg break out boards then to a MIDIBOX DOUT BOARD.

    This: https://www.sparkfun.com/products/10680 ?

    You don't need that if you will use DOUTX4 PCBs. You can get creative with how you assemble IDC cables, no need to follow the original order or total number of conductors.

     

    6 hours ago, doc.g4 said:

    i thought i could connect a  second 72 led matrix into SR U12 via q4-q7

    I guess you could consider defining an 8-row matrix?

    If you save one shift register but give yourself a wiring headache, maybe the simpler approach is better. See ilmenator's approach for an 8x8 RGB matrix. 

     

  5. 8x24 LED matrix

    in MIDIbox NG

    Posted

    Still not totally easy to follow but I get more where you're coming from. I would prefer to draw it out as a logical table rather than a netlist. Are the LEDs on boards and you want to use DOUTX4 PCBs to drive them? Or are the shift registers also on your LED boards? 

    4x source rows as selection pulses will work, though you get no faster multiplexing as that's limited to a doubled 4x pattern. But colours can only be 16 columns wide. 

    If using DOUTs, you could buss two IDC10 ribbon cables and define them as one matrix but you still need a second DOUT to drive the 'second' matrix (third LED board). I would suggest simply to use 3x DOUTX4 boards and define three separate matrices with 4x source rows each. 

  7. 8x24 LED matrix

    in MIDIbox NG

    Posted

    MB_NG supports multiple matrices. You just need to define the shift register where each block of 8 is connected. If any block is less than 8 wide, no problem. It will just take more shift register chips to address them. 

    Best idea is to draw a circuit diagram of how the LEDs are arranged. Then for each contiguous block, that is one shift register with a maximum of 8 rows or columns. You probably need sink transistors (NPN) on the rows unless your current draw is low. 

    Please keep posts public so other travellers can benefit from any knowledge or lessons. 

  8. 8x24 LED matrix

    in MIDIbox NG

    Posted

    You can create a matrix with 9x rows (sink side) and 8x3 columns (R/G/B source sides).

    So you need 5x 74HC595 chips because they only have 8x outputs. You also have 7x rows spare as it is a 16x8(x3) matrix.

    If you have buttons you can connect 1x DIN 74HC165 chip to the columns with diodes to the switch inputs. 

     

  11. midiphy SEQ v4+

    in MIDIbox SEQ

    Posted

    Hi Simon and a happy new year to you too!

    We try to keep track of the "successfully built" SEQ v4+s in this thread, so I don't think you got a serial number yet as you were posting in the "troubleshooting" thread? Happy to assign you #39 if you want to post a pic here?

    Best,
    Andy

  12. midiphy Eurorack Expander Modules

    in MIDIbox SEQ

    Posted

    Hi,

    What meters do you have? Some have a "high-res" function that is activated by holding the backlight button (Fluke meters). Another option is to buy resistors with better tolerance (e.g. 0.1%) but they will be more expensive. In the end, the CV is calibrated on the SEQ and has a variable gain with the first op amp stage. So you should be fine.

    For more than eight outputs, simply chain the J19 data from the superDAC board. RC1 should still be set for all DACs. 

    Best of luck and happy new year!

    Best,
    Andy

  14. Trying to figure out LED resistor values (and also my MB6582 Lives Again!)

    in MIDIbox SID

    Posted

    For time-multiplexed LEDs you can exceed the 20mA current rating or whatever the datasheet says. Some even give a peak current rating that is valid for a given duty cycle (normally 10% rather than our 12.5 or so) and pulse time.

    Totally depends on your LEDs. A tip is to use super bright ones, but probably you already have something installed. In the SEQ v4+ we use 47R but these are superflux RGB LEDs designed for more forward current. Generally the higher the pulse energy, the lower the lifetime of the LED. 

    Keep in mind that the 74HC595 outputs are overdriven in this configuration. Your +5V rail will sag and in the worse case it won't be enough to power the PIC properly. But many MIDIboxes work fine like this :).

     

    • Like 1

  20. cv - multi - levelshifter?

    in Miscellaneous

    Posted

    Yep, this is how AOUT modules work!

    For the switchable solution I developed quad-channel THT boards, should still have some available if you are interested.

    Otherwise: op amp with gain, two inverting amps in series, second with switchable gain also as a summing node (offset for bipolar CV).

  25. midiphy SEQ v4+

    in MIDIbox SEQ

    Posted

    3 hours ago, gresade said:

    I want to extend my Midibox SEQ V4 with CORE_STM32F4 and V4+ firmware that is based on wilba CS frontpanel with midiphy PCBs. But I did not find schematics to check the connector pin signals, if they are compatible. From first sight it looks like it may be possible. Specifically I want to use:

    Sure, all parts and ports are compatible.

     

    3 hours ago, gresade said:
    • RES-SD PCB to add a SD-card socket (this one is not super important)

    You can also use a wCore if you prefer to breakout your SD card and LEDs to the rear panel, otherwise the DISCO core should work without requiring RES-SD. The wCore J16E header is a combination of J16 plus the LEDs on the DISCO board plus reset.

     

    3 hours ago, gresade said:
    • MIDI8 PCB instead of using the longer-size 2xMIDI_IO

    Just as you wrote

     

    3 hours ago, gresade said:

    The I2C header is 1:1 pinned with the corresponding I2C header on the Core. So it is more convenient to wire up. You can of course go for 8x I2C outs with the firmware "hack", but this was not implemented in the midiphy SEQ v4+ on TK.'s recommendation. Still, it was shown to work in at least one case, so if you feel it is worth it, go for it!

     

    3 hours ago, gresade said:
    • LINETX PCB for the line transmission to eurorack extension

    Basically the same

     

    3 hours ago, gresade said:
    • Eurorack modules (I read they should be compatible somewhere)

    Yes, all fine, AOUT (not AOUT_NG) in the SEQ config.

     

    3 hours ago, gresade said:

    Are the connectors on these boards compatible to the  CORE_STM32F4 connectors? Is there a documentation on the board schematics (especially the connectors pinout)?

    There are schematics on the wiki but all was designed to be 1:1 pinned with existing boards.

     

    3 hours ago, gresade said:

    Looking at the I2C PCB , there are 4 flat-cable connectors at the bottom at the board, what are they good for? I need more Midi outs, not ins, so maybe sticking with the MIDI_IO and using two I2C PCB to get 8 outs may make more sense (especially space wise), the Heidenreich case has not so much space.

    The I2C modules can theoretically connect analogue inputs and the ADCs are quite decent. So these headers are used to connect the AINs. In practice there is nothing in the software to scan them, so the headers should remain unpopulated unless you plan to write I2C drivers/modify the app.

    Greetings,
    Andy

     

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