MIDIbox Report

My electronics/Software/Firmware projects haven't stalled. It's the creative process I'm blessed/cursed with. Sometimes I need slabs of time not thinking about an idea. To that end, I'm back to working on my MIDI sync "babelfish" and have found a few tools that help me to do it using truth tables.

Truth tables are charts which layout the array of input and output states of a logic device. For a device that will be used to pop out large, but relatively simple, high and low logic states to operate analog sync signals, creating a 2 dimensional array of the output logic is a simple and reliable way to make 4 channels switch on and off at 48 pulses per quarter note (PPQN), 24 PPQN, 1 PPQN and one pulse per bar (for controlling the tempo of my SY-1 guitar synth pedal) is relative easy to configure with arrays. Simply increment an "address" count using an interrupt, and access each address in the 2D array. Working on the initial premise that all of my timings will be X/4 (eg 2/4, through 3/4, 4/4 to 5/4, et al), it's possible to make this address count truncate at address 192 for 2/4, 288 for 3/4, 384 for 4/4, and so on. Trouble is, it's a huge table of data. Flash RAM on an Arduino, even a Mega, is pretty limited. This data needs to be kept in PROGMEM.

Just making the table large enough for 4/4 used 4/5 of the flash RAM on an Uno, but storing it in PROGMEM allows for some quite large data, especially as this truth table approach allows the actual project timing to shrink to the size of postage stamp. Using the PGMWrap library, by Chris--A, even makes storing large data blocks as transparent as using flash RAM.

So, now the actual nuts and bolts clocking code comes down to the interrupt timer library, Timer1 (Paul Stoffregen), Paul's FreqMeasure library for slaving to tap tempo, click track or MIDI Beat Clock (24PPQN) and the nonblocking AsyncLCD library (Paulo Raca) for a simple 2004 or 1602 LCD display. Just about everything else is external amplifiers, switches, buttons and knobs. There's more than enough room for all this in PROGMEM, even on an UNO.

Comments

Post a Comment

Popular posts from this blog

Removing Ollama From My Mac

The AI experiment in my "laboratory" is over. I've been running Ollama locally on my laptop, as in:- an 8G, local, offline language model, running on local, offline command line software. Don't get me started about the carbon pollution environmental disaster being created by serverside queries to AI like, "Does my partner really love me." The local-only model seemed like an affordable and accountable approach and my M1 Mac is energy efficient fast enough that even really tricky queries were sorted way under 2 minutes. The thing is, I never got a single, useful response to a query. Not one, that was fit for purpose, anyway, out of Ollama's "mouth." I figured that between my ability to describe a problem, and its probable solution, architecturally and simply, might result in useful code fragments for my various microcontroller coding and OpenSCAD design tasks. Not one. The work required to make anything useful was at least as much as designing i
Read more

ALWAYS read the PDS

Image
I'm quite open about my health in public. I'm also a bit of a "helicopter pilot*" when it comes to my cycling, too. So, when I saw my cadiologist last week for an annual followup since my poofer went futt back in 2020, a new doc every year (I'm public, not private), I made sure Doc knew the back story, the front story, the story behind the story and the cover story. I told Doc that my diabetes had been formally retyped, that my "endo" had officially determined that my 2005 type 2 diagnosis was wrong, I'm a type 1. Probably late onset, but things about my childhood and youth health... you know... Maybe I'm latent Type 1, maybe I was a sort of slow burn juvee Type 1. Anyway, Doc acknowledged it, "Ah yes, late onset." I told Doc I've used a bicycle for transport all my life, was a big advocate for cycling for environmental, urban and personal health and that was acknowledged with an enthusiastic, "Very good." Then Doc pre
Read more

Open Source Is Essentially Socialist

Image
I never knew such a thing existed until a few nights ago, but there's an open-source housing project called WikiHouse , described as, "Simple, beautiful, zero-carbon building, for everyone." It's not a perfect open source project, the CAD file formats are mostly commercial, online and industrial grade, although there is a FreeCAD tutorial on how to convert wikihouse cad files to the open source FreeCAD application, it's still complex and largely inaccessible to those not trained in industrial design software. Switch house, source WikiHouse.cc As yet, there are no PDFs for those with an electric jigsaw and a pallet load of ply sheets, a truly accessible format, but the WikiHouse is an example of the idea of open source being a way to drive a socialist economy, without a top down management system. The principle of the whole WikiHouse concept, as I see it, is that housing is a human right, not something that is to be exploited by renting out hoarded property to t
Read more