without this we have ghosting problems on the bottommost keys of the
teensy side
thanks to hasu (on geekhack) for the suggestion, and PrinsValium for
confirming erratic behavior with his firmware without these delays.
thanks DOX for making the changes and trying it out. i'm just adding it
to the repo.
apparently, sublists need to be indented 4 spaces (1 tab) or more to be
recognized as such (because subsequent lines of a list may be indented
up to 3 spaces). it's right there on the markdown syntax page, but i
didn't catch it the first time.
also, mcp23018_init() needs fixing: `twi_stop()` needs to be at the end
of transmission blocks. i wouldn't think that would be necessary, but
it seems to be the only thing that'll make it work, and it also seems
consistent with the protocol diagram in the datasheet (lol, imagine
that), so i think that's what i'll have to do. not as though it matters
much i guess, since it's a single master / single slave system anyway, i
was just hoping not to release the bus till i was finished..
- fixed some includes (`uint8_t` comes from a header, not the language)
- put code from some of the .h files into .c files
- now using open drain logic (hi-Z or GND) on both chips instead of
driving the row pins high on the teensy, or using a pull-up resistor
on the row pins with the mcp23018
- put `return 0;` at the end of some functions that weren't void
- fixed/updated some documentation; esp. the row assignments for the
mcp23018
- generalized the unused/row/column pin assignment and init code using
macros, so they'll be much easier to move around if necessary
- fixed a redefinition error in "lib/usb/keyboard-usage-page.h"
also, i didn't make a note of it in the *.md file, but Waveform
Generation Mode 15 for fast PWM wasn't working right (well.. wasn't
working how i expected it to). i misinterpreted what the modes were
doing, partially (haha, or all-ly?) because i didn't read the
description of fast pwm thoroughly enough... in any case, all the
information's in the datasheet, and it's actually not terribly long.
i'm not sure how to correctly use Mode 15 yet, but i think i'll leave it
alone for now, since Mode 5 works as expected, and i think what the
datasheet says about *that* makes enough sense to me for me to be
content for the moment.
Ben Blazak