Tutorial - How to upload arbitrary data to STM32F4 Flash Memory

Uploading binary data to a desired address


Gecho has one megabyte of FLASH memory, and only a fragment is occupied by standard firmware.

You might need to use this process, if:

  • you wish to extend the functionality
  • you need to store larger amount of data
  • it is not handy to pack data into source files (as constants etc.)
  • you want to be able to replace this data without interfering with firmware

Connect your SWD Programming Adapter and start STM32 ST-LINK Utility.

Into the "Size" field, enter 0x100000 - this is a full range of FLASH memory available in our MCU - and click "Connect to the target" icon.

Tutorial - How to implement new channel

Implementing New Channel - A Rudimentary Drum Machine

Objective: Demonstrate how easy is it to expand the functionality using the framework, showing examples of how to:

  • add a new channel with any numeric code we want
  • enable or disable standard features that are available, to borrow some functionality from other channels
  • upload arbitrary data into FLASH memory and access it, this is handy for lot of other things too
  • decode binary 16-bit PCM sample data from a standard WAV format
  • play multiple instruments in parallel, from FLASH memory with zero waiting state and no need for buffering in SRAM
  • bind this new functionality to existing controls
  • mix the signal output from our custom function into the loop with or without delay/echo

Requirements for any Gecho firmware programming

Gecho Loopsynth - Little bit of background

Making of the Synth

Pocket-size subtractive, hackable DYI synth

Making of the Synth

I have been fascinated by synthesizers from very early age. My best friend's dad ran a wedding-playing band and he owned Roland JX-3P (just guessing the exact model now, from my memory of silver buttons with red LEDs inside). When he allowed us to touch it after lots of nagging, and we powered it on, my ears immediately noticed it was something out of this world. I was born in Czechoslovakia, a country run by communists, where we spent our days duplicating 10th copy of illegally imported tapes through cheap "International" branded double decks.

Gecho The Awesome Loopsynth


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Gecho has acquired funding for the initial production batch:

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