Can we get a dimmer minimum brightness?

[RetireeJay46]

I've built a bedside alarm clock using the Adafruit 1.2" 7-segment clock display with I2C Backpack. I'm using CircuitPython on an RP2040 Feather board, so the software library is this one: Adafruit_CircuitPython_HT16K33.

The issue for me is that the minimum brightness I can achieve is still too bright. I'm no expert on the details of how these systems work, but it appears from lines 95 to 103 of "ht16k33.py" here that the brightness is actually constrained to values from 0x00 to 0x0F, i.e. 16 possible values. But the brightness of 0 is definitely not "off" (at least not when set by "display.brightness" in my program). For example, if I command a brightness of 0.01 - which would translate to 0 when filtered through lines 95 to 103 - it is on, and still brighter than what I would like.

Obviously there's an underlying code somewhere that actually implements the brightness control. Given the digital nature of the system (no analog parts) I presume that the brightness must actually be the duty cycle of a pulse train. So is it possible at the level of the underlying assembly or C code to expand the range of brightness settings, particularly with an eye to providing a dimmer minimum?

[caternuson]

Obviously there's an underlying code somewhere that actually implements the brightness control.

In this case it is a hardware feature of the HT16K33. So this will be a limit of the HT16K33. It only supports 16 levels of dimming with "0" equating to 1/16 and not actually 0:

[RetireeJay46]

Looking at the spec sheet for the HT16K33, I agree that it looks like the duty cycle is built into hardware with only 16 settings.
But maybe there's a hack. The chip can drive as many as 8 columns and 16 rows of LED's, for a total of 128 LED's. But for this 1.2" 4 X 7 segment clock display we are only using 4 X 8 = 32 LED's. So maybe if we programmed the HT16K33 to think it was driving 128 LED's, the time spent driving phantom LED's would be taken away from the real LED's; that could give us a 4:1 reduction in brightness.

[RetireeJay46]

Upon close examination of the HT16K33 documentation, I don't see any provision for expanding or limiting the number of rows and columns that will be output to LED arrays. The application notes simply show more or less LED's actually wired up to the chip. So, it looks like my hypothetical hack won't work. Theoretically I could put resistors in series with the row outputs, but that's too difficult. Sigh.