Now that I had full confidence in my ability to communicate with the LED matrix, it was time to get more comfortable.
The code translation went great, there's really not much to the original except some bit shifting. So things were looking up - maybe I was past the headaches.
Then I tried to output some text to the display. Oops. Pictured above is my attempt at "Hello."
It appears that the Kello engineers wired up these LED matrixes in a ... unique way. Attempting to address individual columns in sequence is not going to work.
I was hoping to make this project relatively display-agnostic, maybe make it support anything HT1632C. Looks like that won't quite be doable. In the meantime, I'm going to have to write an abstraction layer over the display addressing to fix the bizarre panel orientations. But at least the problem is pretty clear.
But hey, isn't the display pretty? No regrets.