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    Speed would need to be up to 2mhz. Iím designing...

    Speed would need to be up to 2mhz. Iím designing a harware module that acts as a man-in-the-middle between a keyboard assigner cmos (that reads a keyboard matrix and generates a 4-bit keycode signal)...
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    12-bit parallel data Vs FTM's

    I'm trying to figure out which pins to assign to a 12-bit parallel data line (all sync'd). At first i thought I'd group the pins by GPIO port, for example on t3.6 GPIOC has pins...
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    Also wanted to mention, this is a much more...

    Also wanted to mention, this is a much more responsive & steady clock for the critical timing of my project. Before, I was using midi cc to alter the speed of the 1mhz clock using ...
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    This worked for me on pin33. Thanks for the leg...

    This worked for me on pin33. Thanks for the leg up! Gave me a very nice 1mhz signal. I love examples :) Using that code and the port mappings in your link, I was able to modify this to work on pin3....
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    I had this problem recently, TeensyDuino kept...

    I had this problem recently, TeensyDuino kept telling me it could not compile for Teensy 3.6. couple of suggestions;

    1. delete arduino 1.89 and reextract zip file, then re-install teensduino. That...
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    Thanks defragster. I am buffering the pwm output...

    Thanks defragster. I am buffering the pwm output so iíll see if i can drive it directly from pin 3 while still feeding the clock to the rest of the signal chain.
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    Maybe i misinterpreted what it can do. From the...

    Maybe i misinterpreted what it can do. From the link you sent, which I read through a couple times, it seemed like it could only display a frequency measurement. Like if you feed it a 1mhz clock it...
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    i think iím gonna have to learn about using FTM...

    i think iím gonna have to learn about using FTM timers, as Theramingenieur mentioned. Itís just really heavy stuff for a novice, and not many examples around to get the ball rolling.

    getting an...
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    Thanks Tactif, Examples are always very...

    Thanks Tactif,

    Examples are always very helpful. Which teensy model did you use this for? Iíll see if i can do a search in the datasheet to see if i can easily adapt this to pin 3.
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    Is it possible to watch a pwm output (lets say up...

    Is it possible to watch a pwm output (lets say up to 1mhz) and increment a counter on every positive clock pulse?

    Iím using pin 3 FTM1 timer (linked to only pin 3 & 4) to generate a variable pwm...
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    Thanks, that worked adding it at the end. I'll...

    Thanks, that worked adding it at the end. I'll keep the main loop relatively clean, does usbMIDI.read need to be in there or can it be flagged also by interrupts? Is the idea to keep as much out of...
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    Hi Paul, thanks, heres the code in full. I'm...

    Hi Paul,

    thanks, heres the code in full. I'm just trying to get the interrupt to write a pin high/low, siiliar if you were polling with digitialReadFast and digitalWriteFast. I assume the avr...
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    I'm trying another approach first just because my...

    I'm trying another approach first just because my knowledge of registers is infantile atm. Since the t3.6 is now generating the 1mhz master clock upstream in the instrument, the keyboard assigner...
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    Iíll use 128, thanks. Maybe the hantek is off...

    Iíll use 128, thanks. Maybe the hantek is off calibration, i did open it up and adjust the variable capacitors for its 1khz test signal a few weeks back. Do people calibrate using higher test...
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    Cheers. Thanks for the pointers. Iíll start...

    Cheers. Thanks for the pointers. Iíll start reading into this.
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    so ignore the analogWriteFrequency and...

    so ignore the analogWriteFrequency and analogWrite functions and create a pwm signal directly by writing to the registers? This is a bit over my head, but I'm good at running with examples. If I have...
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    PWM @ 1ghz 47%-53% duty issue

    I'm generating a PWM clock that varies between 1mhz to 191khz according to a midi cc controller. Ive been reading up on duty-cycles in variable pwm situations and have tried to design this in...
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    Data Pins are limited to 25ma, but there are two...

    Data Pins are limited to 25ma, but there are two 3.3v pin that can power external devices. I think iíll need a seperate power source eventually, but its useful in the short term not needing to use...
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    Ah, too much faith i had in the simulation. I...

    Ah, too much faith i had in the simulation. I spent a couple hours playing around with resistor combinations and i found the sweet spot. I did need to add a 22p cap + 3.3v zener at the teensy pin to...
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    I’ve gotten a little further but im having some...

    I’ve gotten a little further but im having some issues. I’m using the T3.6 3.3v pin as the 3.3v source at the collector (source). The base (gate) is connected to the internal keyb. ground, the only...
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    Indeed it does. Unfortunatley I had to relocate...

    Indeed it does. Unfortunatley I had to relocate to Australia this year and all my schtuff is in storage in Seattle, including my awesome soldering station. Everything like that is double the price...
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    Iíd have to alter the resistor choice, 1k is...

    Iíd have to alter the resistor choice, 1k is probably the max impedence working with a clock at 1mhz. R2 and R3 addís a dc bias to the ac coupled signal, so they can likely remain at the current...
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    Yamahaís proprietry keycode system, used in...

    Yamahaís proprietry keycode system, used in everything from CS-01 to Electones. They use a weird key matrix, on a 61-note keyboard itís 5x12, which Highly Liquidís UMR2 doesnít support. I figured if...
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    I copied the schematic in the 4050BP datasheet to...

    I copied the schematic in the 4050BP datasheet to emulate 1 of itís channels in conjunction with Your circuit, Paul. It certainly helped visualise everything. A npn FET seemed to work better @ lower...
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    Attaching screenshot showing 54us sync signal +...

    Attaching screenshot showing 54us sync signal + dataline 2 (of 4). I found triggering to the sync signal was where you can really see whats happening.

    16697
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    Yeah its definetley rated for 20mhz, its the...

    Yeah its definetley rated for 20mhz, its the 6022BE.

    Damn this -15v logic, i see why they did it, to isolate the analog and digital components, but it surely makes it more complicated. If, for...
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    Thanks for the advice, paul. I will experiment...

    Thanks for the advice, paul. I will experiment with the values you suggested. If i buffer with a PNP, perhaps i’ll use a 4050 to clean up the way the data lines come out of the npn. Even the...
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    Yeah i can take screen capture today, though it...

    Yeah i can take screen capture today, though it will only be two channels, 54us sync + 1 (of 4) data line. I just have a two-channel 20mhz usb scope.
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    I emulated the circuit in everycircuit app,...

    I emulated the circuit in everycircuit app, understand now what it is doing. Not sure what killed the chip but it could have been a short on the wires, or maybe my cheap 3.3v breadboard power supply ...
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    Hi Peter, i did try but didnít get any results....

    Hi Peter, i did try but didnít get any results. Iíve discovered the wonders of circuit simulation via the sesame street version of spice (everycircuit), so iím gonna build your circuit in there and...
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    I breadboarded it up, it fried my 4050BP chip ;)...

    I breadboarded it up, it fried my 4050BP chip ;) no worries i had spares. It got very hot, if that helps.
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    Thanks Paul! I actually had run out and grabbed a...

    Thanks Paul! I actually had run out and grabbed a bunch 2n3904ís and 2n3906ís before i read this, serendipity, and have a ton of 4148ís. No chance of it going positive, but iíll incorporate the diode...
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    If i can just get the -15v to gnd digital signal...

    If i can just get the -15v to gnd digital signal to +15v gnd, i believe i can just use a CD4050 hex buffer to do the level shifting to 3.3v. The data sheet says the inputs can be up to 15v l, even...
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    Ah yes, i see your point. I have +/- 15v rails...

    Ah yes, i see your point. I have +/- 15v rails (close enough) inside the organ.

    Assuming i canít go over 1k impedence for the 1mhz clock signal before it messes with the waveform shape, can i...
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    Thanks for that, I will breadboard it up and see...

    Thanks for that, I will breadboard it up and see how it operates. It seems more stable than a bipolar opamp by design.
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    Iím wondering if iíve made it overly complicated....

    Iím wondering if iíve made it overly complicated. The original circuit uses a 4050BP non-inverting hex buffer, wired in an oddish way; its supply voltage is connected to gnd and the Vss is tied to...
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    Inverting shouldnít be a problem, just a change...

    Inverting shouldnít be a problem, just a change of logic in the teensy code.

    This part looks similiar but is designed to work at 3.3v;

    http://www.mouser.com/ds/2/149/FODM8061-95625.pdf

    Just...
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    Maybe a phototransistor based optocoupler? Such...

    Maybe a phototransistor based optocoupler? Such as;

    https://docs-apac.rs-online.com/webdocs/12cf/0900766b812cf975.pdf

    No power supply pin, just whatever is present at the collector.

    Not sure...
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    Iíd just read its almost common practice to add...

    Iíd just read its almost common practice to add 3.3v zeners on the inputs for protecting pins, anode to ground. If i add the zener before the rc filter, no voltage drop but i see negative voltage...
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    Iíve been breadboarding some 3.3v zener diodes...

    Iíve been breadboarding some 3.3v zener diodes after the RC filter ive created (on the opamp outputs), since the gain on the opamps brought the signal to around 0v-3.28v (ish), i didnít expect a 3.3v...
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    Iíve figured it out. I simply need an RC lowpass...

    Iíve figured it out. I simply need an RC lowpass filter on the oupuf of the opamps going to the teensy pins. That gets rid of negative spikes. I guess a -3db filter around 1mhz should suffice.

    The...
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    Thanks Paul, i will look into all these points...

    Thanks Paul, i will look into all these points you highlight, definetley some things I hadnít considered.

    Iím attempting to do 12 channels using 3 quad opamps using tl074ís (best available without...
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    ah, poor opamp circuit design on my part, needed...

    ah, poor opamp circuit design on my part, needed to add a small 680ohm output resistor (in addition to input & feedback resistor). The opamp was oscillating, causing spikes into negative range,...
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    One last question or two; Iíve built inverting...

    One last question or two;

    Iíve built inverting opamp channels with gain reduction to turn the (-15v to 0v) logic into (3.3v to 0v).

    When looking at the scope, it looks good but it seems to go a...
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    Thanks. Iíve gone ahead and ordered a 3.6 board....

    Thanks. Iíve gone ahead and ordered a 3.6 board. Appreciate your patience with my questions.

    I think even if it was possible, having room to expand is wise. Not only that but now i can likely do...
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    Is the only difference between 3.5 & 3.6 the 5v...

    Is the only difference between 3.5 & 3.6 the 5v tolerant pins on the former?

    Its a little cheaper here in Australia, and its easy math going from -15v to 5v electronically.
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    I think the engineers at Yamaha were...

    I think the engineers at Yamaha were overachievers ;)

    Iím wondering though, if i setup a 8-bit array already prefilled with the code corresponding to the key (c# to c) and octave data, shouldnít a...
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    Actually i got that wrong, i think it does need...

    Actually i got that wrong, i think it does need to send out a 4-bit parallel code every 1us. Its just does so using 3 nibbles over a 3uSec period (touch data -> octave data -> note data (c# to c).
    ...
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    Hey Paul, Thanks for the reply, shouldnít be...

    Hey Paul,

    Thanks for the reply, shouldnít be too hard i guess to get it into 5V logic.

    Regarding the timing, the 1uSec master clock i believe is divided down inside the cmos chips after...
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    Reading a 1Mhz -15V to Gnd clock

    Hi,

    I'm very new to teensy but thought it could help me with a midi retrofit project.

    I chose the Teensy++ 2.0 due to the 5V tolerance & the number of digital I/O's. I'm working with a...
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