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MCUdude / SigmaDSP

A versatile Arduino library for interfacing with the ADAU1401, ADAU1701 and ADAU1702 audio DSPs
GNU Lesser General Public License v3.0
168 stars 35 forks source link

Reducing memory usage #16

Closed djamps closed 3 years ago

djamps commented 3 years ago

Is there a way to omit the DSP program data from the c headers? I'm currently self booting so it's really not needed, and the arduino's program memory is on a tight budget given the existing program in place. Ideally, I'd like to use this library for control of a few registers, but the parameter data is overflowing my memory. Thanks in advance.

MCUdude commented 3 years ago

Hi!

If you're not using the microcontroller to flash the EEPROM, you can shave off quite a lot.

On my computer, the 1_Volume test sketch compiles down to 16292 bytes on an Arduino UNO. If I comment out loadProgram(dsp);, the sketch size drops significantly and is now only 6738 bytes.

The large arrays in the SigmaDSP_parameters.h file don't get included by the compiler if they aren't in use.

djamps commented 3 years ago

Thanks, that helps alot! Do you have any thoughts on using self booting + MCU? We technically have two bus masters in this scenario. It seems to work ok but I couldn't find any info in the datasheet on exactly how to load the DSP program outside of self boot.

MCUdude commented 3 years ago

Do you have any thoughts on using self-booting + MCU?

This is how I've usually done it. The DSP is only a master for a few hundred milliseconds on power-up, so as long as you give the DSP the time it needs you're all good.

It seems to work ok but I couldn't find any info in the datasheet on exactly how to load the DSP program outside of self boot.

It's quite easy to load the program using a microcontroller on boot; at least with this library. All the test sketches in this library show you how it can be done using loadProgram(dsp). And all the library source code is here if you really want to go down the rabbit hole!

It takes up a lot of space indeed, but it gives you greater flexibility if you have a microcontroller with a lot of flash memory. An ESP32 could for instance have several DSP programs in flash, and load the appropriate one when needed.

djamps commented 3 years ago

Thanks so much for the detailed info and quick replies. I'll consider this case closed :).