Custom build pcbs yours, parts mine + AVR studio programming

Hi. I’ve been building shruti-1 using your pcbs and my parts (had most of them).
I’ve just completed the Digital board, I managed to defuse & program the processor (using AVR studio - so it’s doable, in case someone wants to know), uploaded sysex file with factory defaults then I’ve put a jack to the OSC< output and I must say…

I am completely blown away!
I am absolutely surprised with the amount of effort put into designing this clever device, its sounds and GUI. I am just about speechless. I played with it dangling on two 5v wires while holding audio jack against the osc until 3 am last night! It is so absorbing and so much fun I almost forgot I had to build the filter board ! I havent even tried all patches. Anyway great respect for the work done. That’s really impressive and respect to your programing skills and kudos for the enormous time you must have spent on this project!

Since I’ve been sourcing parts myself, I guess they’re somewhat different than yours. Here’s what I’ve encountered so far in terms of parts compatibility.

  • my LCD display displays some strange characters (probably the charset is diffeeren), e.g. something like superscripted “12” instead of a separator character. For example on the page with 16-sequencer notes, I also get a Paragraph character in top right and Enter character in top left.
    Don’t know what should be displayed here instead. So maybe a hint for your future versions to ensure compatibility - use programmed special characters instead of ROM-ones, as they may differ. For me that’s not really an issue, but maybe it’ll help somehow

  • also my pots are noisy (maybe that’s because I only have the digital board now), anyway… the page sometimes changes back and forth as if I am using a pot, while I am not…

  • the biggest surprise so far: the encoder directions are wrong, i.e. turning it left a value increases, right it decreases, of course it also works the opposite direction in menus.

I guess I’ll give a try one day and try to recompile all sources in AVRstudio (AvrGcc).

best regards and kudos again

  • Regarding the special characters, the Shruthi indeed uses programmed characters (no, the kits don’t come with super-custom LCD modules whose drivers chips have a music note character in their ROM). Your problem must be one of the following: 1/ the LCD module you have is not exactly compatible with the HD44780 standard and uses different messages for setting up the custom characters. 2/ your LCD module has a slow startup time and it misses the sequence defining the custom characters which is sent straight at boot. I’ve tried LCDs from a dozen of vendors and have never observed this problem.
  • I have no idea for the noisy pots. Could be your power supply, or a bad solder join on one of the bypass caps…
  • Do you have the reference of the encoder you used? Someone else had the same problem so I’d rather give a warning in the BOM… You can “rewire” the encoder correctly in software by swapping the kPinEncoderA and kPinEncoderB constants defined in shruthi.h

Thanks for your input.

  • you misunderstood me. I guess there are two kind of HF44780 stanard ROM character sets - one with katakana and the other with Cyrillic.
    I mean, the note character actually displays ok. But here and there still I get a random ones. It seems like they are programmed in the ROM (one looks like Paragraph character (mirrored double P), the other like enter (broken down/left arrow) and the third one like “12” both digits in one field, written as superscript. They don’t look like garbage, so it doesn’t look like it missed programming. From what I’ve noticed this “12” character displays instead the separator character you can switch on/off in the config menu. Two weird characters show up on the splash screen, but I guess they are the shruti logo.

  • I’m now running the board on a 5V after a 7805. So I guess the only reason could be the decoupling cap on the adc vcc side of 644. Otherwise pots. Il check the power supply and add some smd filter caps (1nF or sth) to pot sliders and gnd,

  • I have an ALPS encoder from a German guy on e-bay, not sure what exact type it is. I’ll try one day to recompile the code, but for now, i don’t have enough time for this (i’m win avrstudio user - don’t have the toolchain you’re using python/make and stuff to run your scripts).

thanks again for help and for your god work

Ah I see for the weird char… Yes I’m using displays with the “japanese + graphing calculator” ROM, which is the only ROM I have seen so far. Yours probably has accented letters.