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Old 02-16-2012, 04:41 AM
Jim McDougall Jim McDougall is offline
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Default Patch LED Display

I am trying to see if I can use the MD24 to drive a 3 digit LED display to display patch numbers and I am a little confused because the firmware manual indicates only using 6 bits for the program change mapping but midi patches are numbered 0 through 127 so to decode 127 you would need 7 bits.
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Old 02-16-2012, 04:13 PM
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John John is offline
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Quote:
Originally Posted by Jim McDougall View Post
I am trying to see if I can use the MD24 to drive a 3 digit LED display to display patch numbers and I am a little confused because the firmware manual indicates only using 6 bits for the program change mapping but midi patches are numbered 0 through 127 so to decode 127 you would need 7 bits.
Hi Jim,

The bits are numbered from 0, so there are 7 bits 0 thru 6.

Please let me know if this isn't the answer to your question.
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Old 04-06-2012, 05:24 AM
Jim McDougall Jim McDougall is offline
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Ok -- so how do I get from here to a 3 digit display -- they typically look like this
http://www.ebay.com/itm/320537737104...84.m1438.l2649

how do i get from 8 bit binary to control this? --- all of the led driver chips I have found are 4 bit BCD single segment --- or SPI or I2C multi segment
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Old 04-08-2012, 12:04 AM
Jim McDougall Jim McDougall is offline
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Another possibility cropped up --- can I use the outputs of the MD24 as digital inputs to another processor ? Specifically this one
http://www.coridium.us/PROplus.php

If I take 21 MD24 outs as 3 by 7 bit outputs covering patch changes on three channels then I can write a program that runs on this processor that does the counting and output the individual patch numbers to an I2C connected multi-line display. That would still leave multiple Inputs on this board that I could use to monitor other statuses and use a series of I2c displays on the I2C line.
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Old 04-11-2012, 08:24 PM
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Quote:
Originally Posted by Jim McDougall View Post
Ok -- so how do I get from here to a 3 digit display -- they typically look like this
http://www.ebay.com/itm/320537737104...84.m1438.l2649

how do i get from 8 bit binary to control this? --- all of the led driver chips I have found are 4 bit BCD single segment --- or SPI or I2C multi segment
Really, the best way to do this would be for me to write a LED matrix output functionality for the MD24 outputs and put in some 7-segment modes, like the MIDI CPU has.

Otherwise, you'd want some kind of chip that takes a parallel binary output and converts to a 3-digit seven-segment drive. Not sure if that exists.
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Old 04-11-2012, 08:25 PM
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Quote:
Originally Posted by Jim McDougall View Post
Another possibility cropped up --- can I use the outputs of the MD24 as digital inputs to another processor ? Specifically this one
http://www.coridium.us/PROplus.php

If I take 21 MD24 outs as 3 by 7 bit outputs covering patch changes on three channels then I can write a program that runs on this processor that does the counting and output the individual patch numbers to an I2C connected multi-line display. That would still leave multiple Inputs on this board that I could use to monitor other statuses and use a series of I2c displays on the I2C line.
Yes--if you're willing to do that kind of development, that could work.
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Old 04-11-2012, 11:44 PM
Jim McDougall Jim McDougall is offline
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Great -- Coding for this processor is easy as it has a basic compiler and I have written a couple of programs in this Basic for their smaller processors. It runs this basic at about 10000 lines per sec so it runs very fast -- and the I2C interface working with Matrix Orbital displays is dirt simple. These displays also have matrix keyboard and 6 GPIOs accessible via I2c so if I use 4 displays I could add another 24 digit ins to the same processor if necessary. (Severe overkill !) But I could do brightness and contrast adj by individual.display.
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