planck constant

sunday, 25 june 2017

Split Planck with cherry profile keys

the current Planck (keyboard) state as documented on this site and dotfiles. This page is a continuously updated explanation and history of the keyboard layout iterations.

Notes in the accompanying keyboard descriptions pertain to layout and firmware design. The coding specifics of some of the more unique features of this particular Planck keyboard implementation can be found here.

change history

since finalizing the ergo wide layout concept with the centre two columns dedicated to modifier chords, tweaks still manage to make their way into the firmware to accommodate (my particular) application and desktop workflow.

Little niggles ultimately led to normalizing keys and key relationships between layers to make the layers feel as natural, logical and easy to remember as possible – the mirroring of the left hand key pairs on the number and symbol layers is a prime example. All symbol key layer relationships have undergone a degree of placement rationalization and usage refinement – with emphasis on coding needs.

In chronological order, a long list of tweaks (whose number must be an indicator of approaching completion – or not)! As only the current layouts are illustrated below, it will be somewhat challenging to picture the many keymap transitions from the ergo wide layout starting point. However, the list itself should provide a sense of the iterative process involved in the refinement of this particular Planck layout..

  • the centre column pairings of Shift-GUI, Ctrl-GUI and Shift-Alt, Ctrl-Alt changed to Ctrl-Alt, Ctrl-GUI and Shift-Alt, Shift-GUI effectively aligning Alt and GUI modifiers in their own columns, a grouping which better suits the needs of the window manager work flow
  • the number layer Symbol Layer key is moved left one column position and the symbol layer Regex Layer key is similarly moved right one column position and are now toggled with the ring fingers which feel less cramped than their former middle finger assignment
  • the Caps Lock key is now a one shot modifier Shift key (which is double tapped to toggle the Caps Lock), completing the set of one shot modifiers
  • the Function keys have been remapped to match the numeric keypad layout of the number layer, naturally
  • the double tap key pairs of the number layer have been normalized with the symbol layer by swapping their key positions with the outer column modifier keys (used mainly for window manager desktop actions) which, while looking odd, retain a comfortable pinkie-index finger roll
  • the number layer column of one shot modifier keys has been changed to dedicated Alt modifier chords in optimal row positions (for window manager desktop actions)
  • the number layer Symbol Layer and symbol layer Regex Layer keys are now positioned in their most obvious location (how was any other location considered?) – the middle finger home row! – with the Right Angle key now defined as a double tap key
  • added a Shift Navigation cluster layer to the left Shift Layer, completing the quadruplet (Ctrl, Meta, Alt, Shift) of single modifier navigation chords – the thumb Shift avoids the reach required for the centre column one shot modifier Shift key
  • added the same Shift Navigation cluster layer to the Symbol Layer including switching between shifted and unshifted navigation codes by simply releasing/pressing the Left Shift / Pipe key while the Left (cursor) / Symbol Layer key is held down, whilst allowing rolling between the Shift and Symbol layers seamlessly without the need to lift both thumbs off their respective keys to switch layers (easier to appreciate in use than explain!)
  • dropped the Plover Layer (and other test code) to accommodate the increased size of the latest code base and available flash RAM
  • recovered sufficient RAM space to re-add the Plover Layer by dropping the dedicated Macro Layer (which defined only a single key, the Dynamic Macro key) and refactoring the keymap code – the popular Planck Tri-Layer Toggle (using the Number and Symbol layer keys together) is now dropped in favour of a single Backspace / Macro key (labeled Adjust) to raise the Adjustment Layer and the Dynamic Macro key
  • added the complement of home row one shot modifiers to the Function Key and Shift Navigation cluster layers
  • added the obvious (but overlooked) Shift-Tab to the right Shift Layer
  • added the complement of home row one shot modifiers to the Number Layer (shifting the Symbol Overlay Layer key to the pinkie), moving the Angle Brackets down one row
  • moved the Angle Brackets down one row on the Symbol Layer, and shifted the Regex Overlay Layer key to the pinkie to mirror the Number Layer
  • swapped the Dot and Backslash keys on the Symbol Layer to rolling finger positions
  • added the Angle Brackets to the Adjust Layer in their familiar shift positions (Comma and Dot keys), mirroring the Number and Symbol layers
  • redefined the Number Layer as a numeric keypad with basic mathematical operators – calculator mode being somewhat more useful than straight hexadecimal input – and assigned the Hexadecimal characters to the Hex Symbol Overlay Layer (whose index/pinkie finger locations still look somewhat odd but remain easy to remember) along with the Backslash, Pipe and Tilde keys
  • not a layout change, but fixed the frequent new sentence (left thumb tap plus down) Space plus Shift sequence which the process_user_function firmware latency (as coded) can fail to recognize during rapid touch typing – auto-repeating Space now requires left thumb double tap plus down, and Modifier Space chords are limited to one shot modifier key plus Space
  • dropped the Dynamic Macro Layer to reduce reported flash memory size below 100% – macro recording was being truncated even with reduced buffer allocation
  • redesigned the Number Layer and its associated Hexadecimal Overlay Layer layouts, moving the A B C hexadecimal keys to the Number Layer and D E F keys in their overlay position, so the Hexadecimal Overlay Layer and Regex Overlay Layer of the Symbol Layer can be defined as a single layer (freeing up precious bytes of flash memory space)
  • in lieu of dynamic macro strings, added a compile time double tap macro string to the Function Key Layer (which is flash persistent) – one is good enough for now
  • fixed the one shot modifier restriction side effect of the tap dance Space Shift sequence to recognize all Modifier Space chords
  • corrected similar latency issue with rapid new paragraph (right thumb tap plus down) Enter plus Shift key sequence – with double tap plus down to produce auto-repeating Enter
  • squeezed in QWERTY layout and associated left/right Shift Layers (with similar symbol mappings for non-alpha keys)
  • left symbol (pair) “double tap” keys can now be triple tapped to place the cursor inside the enclosing right character
  • the Adjust Layer now omits all unused QMK firmware settings, relocating the remaining firmware settings to the left hand side and moving the custom macro keys to the right (with corresponding adjustments to the Function Key and Plover layers)
  • lining up the centre column modifiers with the one shot modifiers of the Numberic Keypad Layer, swapping the home row Ctrl-Alt and Ctrl-GUI keys with the top row Shift keys of the centre column
  • completed the available triple tap symbol key pairs

symmetry and overloading

while the Shift, Number and Symbol layers and their overlay layers may appear daunting at first glance, a closer examination reveals a high degree of symmetry and normalization across the layers, with the application of simple shift values for many of the overlay keys (to reduce unnecessary alternate hand layer toggling).

The clustering or keypad approach to numbers and symbols is, perhaps, the distinguishing feature of this particular keyboard layout design (aside from the wide layout) – which, IMO, is more effective than the traditional row oriented layouts (at least, I was never proficient at touch typing the numbers and symbols on full sized keyboards).

The Shift Layers, in particular, add the convenience of remapping the opposite Shift key and other non-alpha keys to provide surprisingly effective access to special characters which the wide layout would otherwise seem to omit. For programmers, the opposite thumb access to the Minus and Underscore symbols, and the Tilde and Slash keys, make for easy entry of mnemonics and path names, as an example.

The keypad and cluster organization applied to other layers similarly require little effort to adopt – of course, having arrived at this design is largely a result of my own fingering disposition, pleasant surprises aside. Overloading keys to shift values further eases memorization.

legend

Keyboard layout legend

default colemak layout

this Colemak layout is based on the Colemak Mod-DH layout with a few adjustments..

Ergo Colemak DH layout

Not adhering to the Colemak ZXCV bottom row assignment, the Colemak V character is swapped with the B character (hence, the B returns to its QWERTY position – this is a higher frequency character and feels better placed there).

Similarly, the M character, being a higher frequency character than the K, is swapped with it on the home row. As well, it feels much less of a reach than on a staggered keyboard.

Lastly, the Quote replaces the Slash character being more useful – all is not lost, see the Shift Layers below for the equally easy to reach Slash and Question Mark.

shift layers

in order to overload keys, most notably, the Comma, Dot, Tab, Backspace and Shift keys themselves, left and right Shift layers are defined in place of the Shift modifier..

Shift overlay layouts

In usage, the overloading of the Comma and Dot keys actually feels quite natural – no more long finger reaches – with the added bonus of the home path name constructions. Similarly, the readily accessible Minus and Underscore feel equally easy to insert.

Switching between Shift and Navigation modes does not require fully releasing the associated layer key, permitting rolling between layers. See the Symbol Navigation Layer.

numeric keypad layer

the Numberic Keypad Layer and its shift symbol overlay share half the hexadecimal character set so that the primary layer may define the traditional keypad mathematical operators..

Number layer

Also, splitting the hexadecimal characters between two layers (freeing the right column mapping) also allows merging the Number and Symbol overlay layers into a single layer for raising (from a firmware perspective) – see Number Symbol Overlay Layer.

symbol navigation layer

switching between Shift and Navigation modes does not require fully
releasing the associated layer key, permitting rolling between layers. See the Shift Layers..

Symbol navigation layer

number symbol overlay layer

the actual single overlay layer referenced by the Number and Symbol layers via the left and right pinkie finger layer keys..

Number symbol overlay layer

function key layer

Function key layer

The Plus key completes overloading the Equal (Backspace) key. See the Shift Layers.

qwerty

QWERTY layout

QWERTY Shift Layers similarly map left/right Shift symbols as defined for the Colemak layout. See the Shift Layers.

plover

Plover layout

adjustment layer

the Dynamic Macro Layer (no longer required with the latest QMK software) was merged with the Adjustment Layer and subsequently disabled for flash memory space. Dropping unused (for my usage) firmware settings permitted dividing up the board into left side keyboard control assignments and right side key codes..

Adjustment layer

Note: Audio ON is defined to enable audio should it be inadvertently unavailable on keyboard boot – there is never a need to disable it!

In lieu of dynamic macro strings, two compile time double tap macro strings are available, one defined within the source configuration and the other at firmware compile time. See the planck build script in the hardware dotfiles.

The Angle Bracket keys complete overloading the Comma and Dot keys. See the Shift Layers.

dynamic macro recording

is a nifty feature of QMK software and has been relaxed to no longer require its own dedicaed _DYN layer. It was dropped from this keyboard because of its flash memory requirements. Losing its buffer contents on USB disconnect also limited its utility – hence, the two compile time macro keyboard shortcuts provided with this layout.

For dynamic keyboard shortcuts, ultimately, macro recording desktop software provide much more flexibility, such as autokey for Linux which allows an unlimited number of persistent strings to be recorded.

boundaries

available memory for flashing on the current board revision is 28K (0x7000). The dozen layers, double tap definitions, dynamic macros and shift navigation left/right layer rollover currently consume over 99% of the available RAM – compilation actually reports 100% usage despite recent changes which should cause over utilization!

Any significant future enhancements to this base will likely require sacrificing a feature or two. Dynamic macros and double tap definitions would likely be the first casualties should I have any other bright ideas.

See change history. But the latest compile time macro string, Space Shift / Enter Shift sequence handling, and Number Layer with corresponding overlay (and subsequent flash memory recovery), may stand the test of time..

───  planck qmk

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