[sdiy] Fet to short pedal input?

[brianw]

On Dec 1, 2025, at 4:02 PM, grant wrote:
> Geez, they have a whole truckload of STM32's in there. And I thought this was the Raspberry Pi musical instrument company...
> 
> On 12/1/2025 5:00 AM, Sean Ellis wrote:
>> 
>> https://www.manualslib.com/manual/2518830/Korg-Prologue-8.html?page=37

I counted a dozen ... yeah, that's a lot of firmware to develop and load onto the chips at manufacturing time.

I'm sure you were joking about the Raspberry Pi, but I can't resist a chance to be pedantic. The R-Pi is based on a Broadcom chip that has a lot of silicon dedicated to GPU functions. That's a lot of power and cost wasted on a function that isn't used in a synthesizer, and multiplying the waste by 12 would really be an issue.

Meanwhile, Korg seems to have selected the cheapest STM32 chips that can handle each task. Four front panel controllers are the STM32F030, which starts at $1.47 each. Six voice synthesizers are the STM32F401, which starts at $2.41 each. Then there are a couple of STM32F446 to coordinate voices, which are $3.22 each. Each one of those is 1/10 the cost of a Raspberry Pi. Some of the the STM32 variations even have 2D graphics acceleration to run the LCD displays more efficiently.

There are probably 10,000 different CPU options for modern electronics design, from companies like Analog Devices (SHARC and Blackfin), Freescale (Kinetis), XMOS, Texas Instruments (TMS320, Stellaris, MSP430), Microchip (PIC), and then many current revisions of classic eighties 8-bit processors as used in vintage hybrid analog synths. Some of them even use picoamps of current, making them great for long life on battery power.

Anyway, that's the end of my Public Service Announcement in 4, 3, 2, 1...