"unselecting" left-hand rows is a wasted i2c transaction.
On the left-hand side, the ergodox uses a GPIO expander. It
does *not* change "direction" (input/output) of pins, it just
sets pins high or low.
But all the pins are written at once. There's no way to
change just one pin's value; you send a full byte of all eight
row pins. (Not all of them are in use, but that doesn't matter.)
So every pin is either +V or ground. This is in contrast
with the right-hand side, which is using input mode to make pins
be neutral.
So there's no need to "deselect" the rows on the left side
at all. To select row 0, you set the GPIO register for the
rows to 0xFE. The previous code would then set it back to
0xFF, then set it to 0xFD on the next cycle. But we can just
omit the intervening step, and set it to 0xFD next cycle,
and get the same results.
And yes, I tested that the keyboard still works.
On my system, scan rate as reported by DEBUG_SCAN_RATE goes
from 445 or so to 579 or so, thus, from ~2.24ms to ~1.73ms.
Signed-off-by: seebs <seebs@seebs.net>
* pull fuse settings for bootloader jump
* fix 32a chips
* make automatic bootloader selection optional
* quantify bootloaders
* fixs #164, speeds up dfu reset
* fix for chips w/o usb
* missing an n
* fix bootloader sizes, use words for addresses
* fix bmini, pearl, and [[ issue, make things quiet
* ignore avr errors on arm for now
* update settings for the light
* document bootloader stuff
* add bootloader title
* Copy the ergodox_ez code to handwired/dactyl
Differences from the Ergodox:
* Use QMK_SUBPROJECT_H instead of QMK_KEYBOARD_H, since it's under
handwired
* Omitted several keymaps. They'll eventually be broken (since the
Dactyl has fewer keys), and I don't want to try to fix them.
* Omitted the keymap images for the default layout, since they depict
a different keyboard.
* Everything that said Ergodox now says Dactyl, naturally.
* [whitespace] Delete trailing whitespace
My editor does this automatically so it's just gonna keep cropping up...
* Cut the dactyl down to the right number of columns
(Remember, throughout matrix.c, everything called "row" is really a
column, and vice-versa).
* Remove LED-related code
* Tighten up the Dactyl's build options
* Whitespace cleanup in twimaster.c
* Hardtabs -> spaces
* No more trailing whitespace
* Typo fix
* Correct the CPU frequency units
The Teensy's CPU definitely doesn't run at 16 petahertz...
* Restore access to ONEHAND_ENABLE
I turned it off in 26d47cb42622d990a7c3335e7fcc151aa3edfbf0 while
desperately debugging; I just wanted to ensure it wasn't causing the
problem I was seeing. It was not, in fact, causing the problem, so it's
back.
Also fixed the swap matrix in dactyl.c, since it still referred to
columns that exist in the Ergodox but not the Dactyl.
* Clearer phrasing about TWI's effect on scan rate
* Fix up the Dactyl's firmware-loading instructions
Sadly, the Dactyl has no hole for the onboard reset button.
* Dvorak keymap for the Dactyl
* The Erincalling Layout
* Erincalling layout: Add a := key
I've been working in Go, which uses := a lot, and it's awkward to type
in this layout.
* Dactyl README: link to the dactyl-keyboard repo
* Add a missing copyright line
I don't know how much this matters? Honestly, it's enough for me that my
name is on the git commit. But hey, let's be consistent until there's a
specific reason not to be, right?
* Dactyl: remove commented-out code
I hate it I hate it I hate it
There's not even any information about what it was trying to do!!!! >:(
* Add a note about the row/column ridiculousness
* [whitespace] realign some constants
* Don't claim B4 is tied to VCC
It doesn't matter at all? I honestly don't know what the reason ever
was. It looks like it dates back to the original ErgoDox and I've never
seen one sentence about the purpose.
I've been skipping that wire for some time, and I promise it works fine.
* Dactyl keymaps: Send RALT for right-hand alt key
Not terribly important but I just like things tidy OK
* typo fix
* Refer to "dactyl.h" explicitly
QMK_SUBPROJECT_H has been working locally, but fails in CI. Strange!
* Dactyl: Don't use QMK_SUBPROJECT_H at all
It's still breaking in CI, even though it was a never a problem locally.
* linux shake-around
* move terminal and browser spawning keys
* add a shift to window resizing keys to free combo up for window management
* "jump to tab" shortcuts for firefox
* change window resize modifiers
* change wm keys
* change wm keys again, and reformat keymap to 80chars
* typos
* language key
* qwerty layer for SO, general cleanup
* adds my xd75 layout
* add secret strings to 'secrets.h' behind compile flag, assign defaults
* macro keys now have defaults (hidden in colinta.h) before any recording, and after clearing the dynamic macros.
* fixed whitespace - using 4 spaces instead of 2
With these changes, the ergodox ez goes from 315 scans per second
when no keys are pressed (~3.17ms/scan) to 447 (~2.24ms/scan).
The changes to the pin read are just condensing the logic, and
replacing a lot of conditional operations with a single bitwise
inversion.
The change to row scanning is more significant, and merits
explanation. In general, you can only scan one row of a keyboard
at a time, because if you scan two rows, you no longer know
which row is pulling a given column down. But in the Ergodox
design, this isn't the case; the left hand is controlled by an
I2C-based GPIO expander, and the columns and rows are *completely
separate* electrically from the columns and rows on the right-hand
side.
So simply reading rows in parallel offers two significant
improvements. One is that we no longer need the 30us delay after
each right-hand row, because we're spending more than 30us
communicating with the left hand over i2c. Another is that we're
no longer wastefully sending i2c messages to the left hand
to unselect rows when no rows had actually been selected in the
first place. These delays were, between them, coming out to
nearly 30% of the time spent in each scan.
Signed-off-by: seebs <seebs@seebs.net>
Rasmus Schults