Analog modeling synth, smallest in the world?

I took the LPC-810 and wrote a MIDI based dsp synthesizer on it.

44.1KHz/16-bit PCM audio with sigma-delta DAC.
15 DCO analog modeling synth with 24db resonant lowpass filter.

It’s at

SCH dsp-G1.jpg

Yes, I tried it on the ATmega and it works but there isn’t enough horsepower to make it hifi.

No, It doesn’t use wavetables. All waveforms are algorithmic.

Yes, it uses a sigma-delta DAC, 16-bits/44.1KHz on a digital pin and not PWM.

No, it doesn’t have analog inputs so the boxed synth uses an Arduino Pro Micro to scan the knobs.

Yes, without the knobs the whole synth fits inside the MIDI-plug and uses phantom power :slight_smile:

I know what you guys are thinking seeing the 8-pin DIP, I can do that on a ATtiny. Yes, you can.

But belive me, the ATtiny has nowhere near the horsepowers needed to do something like this.

It will sound like a toypiano.

I have a couple of hundred of these chips.

Stick it to any Arduino as a synthesizer chip.

It sounds better than a SID.

janost: I have a couple of hundred of these chips.

Stick it to any Arduino as a synthesizer chip.

It sounds better than a SID.

Most impressive implementation.

Thinking outloud... To me, a logical progression to the Arduino would be an API and Arduino library to wrap it all. Or, at least some teaser examples. I saw the full-blown project on Indiegogo, what would be a minimal implantation in the AVR world involve? And, of course, what will be the estimated price of the 32-bit uC preprogrammed?



Its very easy to connect to an Arduino. Just 3.3v, serial Tx and audio out.

The serial is standard MIDI at 31250baud. A real synthesizer in a chip.

Hm, a shield?

A 5 voice instant synthesizer on the Arduino? With a library?

If someone makes the PCB, I would say about $12 in quantities?

Its an ARM chip so 3.3v is a must. But it is 5v tolerant on all its pins.

Its really a dream chip for all home hackers. And it takes almost all the abuse as the ATmega does.

It is really a 30MHz chip but I have spent several months working with it and pushing it to 72MHz without problems. So I settled at 48MHz.

No Xtal needed. All on the internal osc :)

I love the ATmega platform but.. These chips are 8-pin DIP, runs from 1.8v to 3.9v and about 15 times faster than the mega so a hell of a lot more fun.

And yes,

It IS the smallest synth in the world, no doubt. MIDI connected to an 8-pin DIP chip with that kind of sound?


Got it featured on Hackaday.

With some good pointer from my dear friend Ray I'll make an Arduino shield for it.

The NXP LPC-8xx just got to be the best MCU at the moment.

No external components, no Xtals, no nothing. Just 3.3v and it runs at 48MHz with a blazing speed.

Single cycle IO and single cycle 32x32bit multiply.

And full of perferials and 18 GPIO.

Dual UARTs, 4 timers, dual SPI (not limited to 8mbps), I2C, and watchdog and systick timer. All IO-function pins are moveable to any physical pin through the switch matrix.

A real ATmega killer.

And small. A complete ARM Cortex M0+ based synthesizer fits inside the MIDI-plug.