Advanced LED functionality on the ADAU1701MINIZ Board

Hello Michael,

This will do it, although I wish it were simpler. It runs on your -1701MINIZ board:

LED D5 (MP1) flashes according to the index set by pushbutton S3 (MP2). The same index operates a bass control in the above example (of course you can implement whatever desired audio paths). The LED signal repeats every few seconds when the modulo-N counter recycles.

Best regards,

Bob

How about two oscillators, a squarewave running at the blink rate, and a VCO pulse width at say 1/10 the blink rate (or whatever is desired), with the pulse width scaled by the index value? Then just multiply the two oscillator outputs.

Thanks a ton for all the responses! Still have much more to learn for sure!

Hey Bob,

I have implemented the schematic above and it works flawlessly.

A couple more questions... first, every time I selfboot the program it defaults to the number 2 LED selection... not sure I am saying that correctly... no matter how many times I have it set to blink or how many times it is blinking when I power down when I power it up it always comes up blinking twice.

I am not sure how a write-back trigger can be integrated into your schematic.

Also, I was trying to implement Press and Hold functionality such that it would take pressing the switch say 3 seconds to be able to register switch activity and then if no activity for a few second then it stays where it is set. Is this possible without a ton of effort?

I have tried several things around using the 'Press and Hold' GPIO conditioning option to no avail.

Thanks in advance.

Hello Michael,

The Write-back trigger must be provided in hardware. Unfortunately, it was not implemented properly on the ADAU1701MINIZ board, thus it simply doesn't work. To check your software you can force a write-back by shorting Q2 base-emitter with a pair of tweezers (see below).

Forcing a WB as described above does memorize the present status, so when power is cycled it returns to the same place. I do notice that upon power up, the first set of flashes shows one blink less than the actual status -- this resolves with the next flash sequence.

The WB signal must go high on power-down before the -1701 loses its own power. A successful WB trigger design would likely use a comparator or supervisor monitoring the input to the board's 3.3V regulator. When this voltage drops below a level set somewhere above the 3.3V regulator's rated minimum input voltage, it triggers the WB.

You can delay the response to button presses with the addition shown below. With this arrangement, you must hold the button for at least one second (set by source DC3) before it advances the count. Shorter presses are ignored.

Best regards,

Bob