I'm not interested in the key scan functionality so much as I am interested in the 1/9th duty cycle that appears to come with it. I am using an 8x8 matrix, so if my LEDs are running at a 1/16th duty cycle then they're half as bright as they could be, and since I'm driving standard 20 segment bargraphs, they could certainly use a boost.
The bit about tthe 1/9th duty cycle is on page 13:
And the ROW/INT set register is on page 10.
I attempted to write this register using the following code, both in my setup function after matrix.begin() and in my main loop after matrix.writeDisplay() (whch I modified from the example to just show a single pattern), but neither seems to do anything. I tried various combinations of 1's for the bits too:
Wire.beginTransmission(0x70);
Wire.write(0xA0 | B00000011);
Wire.endTransmission();
And yes, I left the address pins unsoldered on the board, so the address is 0x70.
I realize I could probably treat the display as 8x16 and duplicate the output to the other 8 rows and then wire the rows together, but I've got everything wired up nicely and doing that would make a real mess, so I'd rather find a software solution.