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  1. M

    External cv inputs and attenuverters board

    they won't be crazy; the input will go up to 1/2 VREF and sit there (also see here); so yes, there might be ways of dealing with this in software, though doing it in hardware seems to me the better/easier approach. it's a borderline case anyways, it can be avoided simply by not patching...
  2. M

    External cv inputs and attenuverters board

    sorry for being unclear: i didn't say put 100k after all the CVs, i said keep in mind the ADS8688 inputs behave weird when floating (which they will, under certain circumstances, in your schematic as is). that might bother you or not. using a voltage follower + (say) 100k *pull-down* resistor at...
  3. M

    External cv inputs and attenuverters board

    i also have difficulties figuring out what's going on, but fwiw ... keep in mind that the ADS8688 inputs can't float* (because of the way the integrated front end works). that would happen though, if i see it right, everytime you patch an otherwise unconnected cable into one of those switching...
  4. M

    Teensy 4.0 First Beta Test

    received the 1062-beta board -- thanks! no boot-up issues when using external power! (see #1995) quick question about "Drive Strength": i've been playing around a bit with a SPI DAC breakout-board this morning and having difficulties getting it to run reliably. the SPI signals in that case...
  5. M

    Teensy 4.0 First Beta Test

    fwiw / re post #4, the OSC (https://github.com/CNMAT/OSC) and MIDI libraries both work ok. (NB: i didn't extensively test all the various options (like midi clock), and didn't test USB (yet), but sending/receiving OSC via serial/slipserial (to/from a ESP8285 thingie @ 1000000 baud, in this...
  6. M

    Teensy 4.0 First Beta Test

    it's not very dramatic. i mainly wanted to see how fast things can go. fwiw, i've tested with a board which has a 8 channel ADC and 8 channel DAC on the same SPI bus, both devices have 32 bit wide registers, so that's 32 x write16 per ISR. with transfer16 as is, the (unrolled) read/write stuff...
  7. M

    Teensy 4.0 First Beta Test

    question about "FRAMESZ": would it make sense to maybe integrate this with, say, SPISettings? further upthread KurtE mentioned something along these lines ("a) Update Transfer16 should be simple... Just need to update TCR.FRAMESZ - question to self is to change once and back after the...
  8. M

    Teensy 4.0 First Beta Test

    many thanks! (also @mjs513) (oh, and ... with an eye on the 1062, will the pads for the usb signals still be centred / aligned with the VIN/GND pins?)
  9. M

    Teensy 4.0 First Beta Test

    slightly OT, my apologies -- does anyone (or Paul) have the part-number for the pogo pins used on the beta breakout-board? i can't seem to find the right height on mouser ... thanks!
  10. M

    Teensy 3.2 Noise generated by analogread

    fwiw, not 100% whether that's what you're seeing, but i remember i had weird noise issues when directly interfacing the T3.x ADCs with an op amp. a small series resistor (51R or so) fixes/d it.
  11. M

    Teensy 4.0 First Beta Test

    ... just remembered this again. possible that the pinout on p.1 (and above code) is wrong on UART2 / CTS? on p. 472 of the IMXRT1050RM datasheet it says CTS = AD_B1_00, which would be pin 19, right? (whereas AD_B1_01 / 18 = RTS)
  12. M

    Teensy 4.0 First Beta Test

    ok, just removed the 22R resistor and populated the other pad with 220 ohms and ... it works (i didn't add the 1M pull-up yet).
  13. M

    Teensy 4.0 First Beta Test

    perfect, works! (fwiw: using LM1117-5, as above. i've tried with two different 12V supplies, it'll come up every time now; previously it wouldn't boot at all without the MIC803) re T4: should i try with the PMIC_ON_REQ hardware modification (as per #1910)? sounds simple enough, just not...
  14. M

    Teensy 4.0 First Beta Test

    sure (can't do it before Saturday though ..., i'm out of town for work)
  15. M

    Teensy with a 5V step-up transformer?

    fwiw, the "metal synth" you linked doesn't even seem to track V/oct, so from that perspective whatever you end up doing probably won't matter too much ... (i can see a "cut-off" input, which i'd assume at best vaguely tracks V/oct). chances are you'd be fine just by amplifying the 3.3v DAC...
  16. M

    Teensy 4.0 First Beta Test

    should i try to hack my board for PMIC_ON_REQ and see if that helps? just to make sure: i'd put a 2.2M or so resistor between the two test-points (= pull-up), and populate the second 0402 resistor to the right of the 3v3 regulator (+ remove the other one); which values would work? i think the...
  17. M

    Teensy 4.0 First Beta Test

    i'll hook up the 12V supply when i get back from work. what i can say is that the board does boot up properly when i hot-plug the 5V regulator (i.e., with pre-started 12V, only then plugging the 5V regulator), so yes, it doesn't seem to be the LM1117 per se that's causing problems. that said, so...
  18. M

    Teensy 4.0 First Beta Test

    sure, this is one i had access to this morning. yellow is VIN, blue is 3v3: in this case, the 5V regulator is a LM1117, with 10uF at the input + output (this is the thing in question). (the LM1117 here is fed from a -/+12V supply (2.4A), but details here are beyond control of the designer, so...
  19. M

    Teensy 4.0 First Beta Test

    thanks, Paul. i've tried but it doesn't help it, unfortunately. fwiw, i've tried with three different PSUs (both linear and switching), which either feed a local 5V LDO (800mA) or a RECOM DC/DC converter, which in turn feeds the VIN pin. for now / testing purposes, it's not a biggie, i can bring...
  20. M

    Teensy 4.0 First Beta Test

    yeah, hung / not booting, 'temperamental' was vague phrasing, sorry ... it looks much like the issues reported here, PSU coming up too slow; i have some leftover MIC803s (140ms), so i figured i might give this a try, but i'm not entirely sure i'm getting the "button"-vocabulary in the datasheet...
  21. M

    Teensy 4.0 First Beta Test

    hi ... a question about the "ONOFF" pin/signal: it looks as if T4 is somewhat temperamental with it comes to using (certain) external power supplies, much like T3.6 (but unlike T3.2). in the latter case, to make sure the thing boots up properly, a/the solution is/was to use a supervisor (e.g...
  22. M

    TeensyMIDIAudio PCB and MicroDexed/MicroMDAEPiano: Synths based on the Teensy

    fwiw, i've also given this a spin on some prototype module i had lying around https://www.instagram.com/p/BujANL0ot-o/ ... butchered up the code a bit to make it work with CV/gate. it's great fun; too bad coming up with a decent UI and so on would be a bit of an undertaking ...
  23. M

    Teensy 4.0 First Beta Test

    fwiw, it's more questions rather than feedback: is/will be FlexSPI2 as, say, capable as a/the second SPI port? (sorry if this was discussed previously in this thread, it's grown a bit unwieldy). lack of a second SPI port was (to me at any rate) one of the main bottlenecks of T3.2, so me too...
  24. M

    Control Voltage and the Eurorack Ecosystem

    fwiw, there's probably no "go to" way, but you'll probably find there's only so many ways you want to do this. it also somewhat depends on what it is you want to do (pitch or LFO/envelope type CV). your basic two options are: use PWM + filter or a DAC + output stage/filter. the former has the...
  25. M

    Teensy 4.0 First Beta Test

    that i've found, perfect. thanks. trying to get something like the 'flexible scan mode' working, we'll see. ... i've only had the thing for a couple of hours; still have to digest a lot (like is ADC1_HC0 equivalent to ADC0_SC1A, so i'd just use a second DMA channel (as with T3.2) to cycle...
  26. M

    Teensy 4.0 First Beta Test

    great, thanks. i can't seem to find the ADC library though, hence my question ... just the old repo https://github.com/pedvide/ADC edit: ah, ok. hadn't seen manitou's reply, confusion cleared up! thanks
  27. M

    Teensy 4.0 First Beta Test

    hi, got my beta board (thanks!) and trying to read/catch up ... quick question, on p.1 it says "stuff confirmed working [ ...] works ADC". that's re analog.c, right? or the "ADC" library? (in which case i can't seem to find it, just https://github.com/pedvide/ADC )
  28. M

    Teensy 4.0 First Beta Test

    hi, not 100% (and it's getting late here ... ) but shouldn't the line below read AD_B1_00 / 19 ( = GPIO16 | UART2_CTS) rather than AD_B1_01 / 18? https://github.com/PaulStoffregen/cores/blob/master/teensy4/HardwareSerial3.cpp#L61
  29. M

    DC Coupled CS42448 osh park board

    ... the conditioning circuits i've used for O_C won't be entirely suitable for this kind of thing; they're geared towards precision CV / "quantizing", but you've probably figured that out by now. fwiw (i'm not an EE, so take this with a grain of salt), i've made another little thingie...
  30. M

    Audio board lo-fi options

    fwiw, incidentally the SP1200 also came up here the other day: https://www.muffwiggler.com/forum/viewtopic.php?p=2990006 ... the gist being: the SP12/SP1200 should be fairly easy to emulate of sorts using a modern MCU + codec ("fixed" sample rate), or teensy + audio board for that matter...
  31. M

    FM synthesis - 808 drumkit

    fwiw / re 808-ish drums, it should be fairly easy to port some of relevant Mutable Instruments stuff into "audio library" objects. see e.g. https://github.com/pichenettes/eurorack/tree/master/peaks/drums here's a half-baked/aborted attempt (used to work, but haven't tried to compile it in a...
  32. M

    iOS / usb woes

    ... ok, sorry for the false alarm: the midi device started working again after giving it (it seems) a different product name, ie despite the absence of V_USB. same for an old wm8731 break-out board i had lying around (*). so nothing related to iOS 12 or V_USB. the above-mentioned audio device...
  33. M

    iOS / usb woes

    i see, so something did change ... thanks. ... i've never given much thought to finer details of USB detection (or rather, simply been following this: https://www.pjrc.com/teensy/external_power.html ), but poking around a bit, wouldn't/shouldn't this be sufficient to make the host (or ipad)...
  34. M

    iOS / usb woes

    hi, here's a question/issue, which, I suppose, is about iOS rather than teensy: i'm having trouble to get two of my projects recognized as a usb device on an ipad (ipad pro 2017, iOS 12.0, apple camera connection kit). both work fine with a regular/proper computer (macbook pro). the one is a...
  35. M

    wm8731+teensy schematics?

    fwiw, the easiest thing (to avoid having the mod the audio library) should be to simply wire i2s/i2c signals as per the "audio board": https://www.pjrc.com/store/teensy3_audio.html ; the signals are just labelled differently than in the MI schematic: I2S_SIN = RX = teensy pin 13 I2S_SOUT = TX...
  36. M

    Eurorackmodular Teensy/Arduino Sequencer?

    there's no reason why DAC8564 and ADS8343 shouldn't work with teensy, so yeah, it'll somewhat depend on the details, and your DIY skills. - for a _standalone_ sequencer, it might not be a bad choice, mainly (IMO) because the thing comes with boost converters / onboard dual supply, so you can...
  37. M

    clicking noise interference (at higher frequencies) on SPDIF output T3.2 or T3.5

    IIRC that had to do with jitter/quality of the MK20's MCLK at various I2S_MDR_FRACT settings (see here) and downstream: "If you set I2S_MDR_FRACT to anything other than 0 or 1, the MCLK output is terrible").
  38. M

    file.seek(pos)

    fwiw, here's two ways to do this: 1. wait until the header has been parsed, then seek: you'd do this approx. here 2. slightly more complicated, separate the file open / file parse, play/seek, and stop/close operations, and keep a "prefetch" buffer, as was done here. the advantage being it...
  39. M

    Getting +/-5v audio signals into the Teensy 3.x analog inputs

    note the schematic doesn't show the low pass / capacitor in the feedback path (it's value will depend on the sampling frequency; in case of OC: 560p ~ 8.6kHz cut-off / 16.7kHz Fs); also that's the kind of (DC-coupled) circuit you'd use for CV inputs rather than audio; i guess it'll do for...
  40. M

    Getting +/-5v audio signals into the Teensy 3.x analog inputs

    if you want to omit the +/- 12 V bus, you'd have to bias the op-amp* differently, like so: that's the circuit used at the O&C outputs, rather than inputs. in that case, V_out = - (R2/R1)*V_in + (1+R2/R1)*V_bias. R1 is typically/conventionally 100k ("high" impedance), so for a 10V input range...
  41. M

    3.6 as a Modular Synthesizer DSP

    mmh, i'd also think this might be something of a niche requirement. but *if* this is going to happen, for the sake of DIY, i'd vote for one that can be soldered by hand easily, ie CS42432, CS42448, or AD1937/38/39 rather than the TI or Maxim ones. or would the pretty big if involve a PJRC board...
  42. M

    Teensy 3.x and SH1106 OLED via SPI

    yeah, i remember he mentioned something about trying. but i don't think he didn't followed up on it. one thing to make sure is the SPI clock is actually putting out 30MHz, not 60MHz or something, which might be too much for the display to stomach. (see...
  43. M

    Teensy 3.x and SH1106 OLED via SPI

    have you tried the gutted code / set-up works with 3.2? anyways, while the OC code as is compiles for 3.6 (and i suppose for 3.5), i think you'd only get static on the display (... is what i've heard. i haven't looked into this myself, because my kickstarter 3.6s got lost in the mail). i'd...
  44. M

    3.6 as a Modular Synthesizer DSP

    neat, our vague schemes for an OC mk2 looked somewhat similar, minus the extra SRAM; and still focused on CV applications, mainly. fwiw, the main bottleneck in the existing version was/is the single SPI port on the MK20; running the display and DAC off the same bus was ok for the intended use...
  45. M

    Who has already got his / her kickstarter teensies? (international shipping)

    sure, i had sent a message on the 22nd. all sorted now. thanks for the refund.
  46. M

    Who has already got his / her kickstarter teensies? (international shipping)

    or what's the preferred way of contacting you? PMs to PaulStoffregen on the forum are disabled.
  47. M

    Who has already got his / her kickstarter teensies? (international shipping)

    ok, i've sent a message via kickstarter. thanks!
  48. M

    Who has already got his / her kickstarter teensies? (international shipping)

    same here, shipping to Germany. should i be worried? or contact UPS?
  49. M

    K66 Beta Test

    quick question: am i reading the MK66 datasheet correctly in that (unlike T 3.1/2, but like T LC) there's no 470R resistor connecting V_REFH to VDDA, right? (sorry if this has been addressed/answered before. quick search didn't turn up anything)
  50. M

    Audio: How to start SD files from a particular point, not the start

    here's one way: https://github.com/mxmxmx/eurotrash_mkII/tree/master/soft/libraries/Audio that's coming with some primitive prefetch thing, too.
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