Add PrtSc to the numpad, filling the nav block

Between Del and PgDn, which makes the nav block a solid 3x2 and leaves the
arrows isolated by a symmetric pair of gaps rather than three asymmetric ones.
26 keys. PrtSc earns a key because it is the screenshot key on every Linux
desktop; Insert, ScrLk and Pause stay on a layer.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Documents/bom.csv

@@ -23,7 +23,7 @@ HALF-L/R,Split,D-ESD,1,ESD 5V bidirectional,PESD5V0S1BA,C2827694,SOD-323,Extende
 HALF-L/R,Split,J3,1,3-pin header DNF,JST SH,-,-,Consigned,0.02,"*** DNF INSURANCE *** VCC/GND/DATA fallback if SBU proves flaky (bad cables). 3 pads cost nothing"
 HALF-L/R,Split,-,-,SBU1+SBU2 TIE,-,-,-,-,0.00,"Tie A8 and B8 together on the board. SBU is CROSSED in the cable, so this makes it orientation-proof and doubles the conductor"
 NUMPAD,DNF,J1/U3/R3/R4/R5,0,DO NOT POPULATE,-,-,-,-,0.00,"*** From the ALL block: numpad MCU has NO connector of its own. Its D+/D- route internally to hub downstream port 1. No connector = no ESD part and no CC resistors needed. Saves ~$0.19"
-NUMPAD,Matrix,D1-D25,25,1N4148W,1N4148W,C81598,SOD-123,Basic,0.011,"25 keys: 14 numpad + 9 nav + 2 thumb (Enter 2u, +). No Num key"
+NUMPAD,Matrix,D1-D26,26,1N4148W,1N4148W,C81598,SOD-123,Basic,0.011,"26 keys: 14 numpad + 10 nav (incl. PrtSc) + 2 thumb (Enter 2u, +). No Num key"
 NUMPAD,Hub,U4,1,USB2.0 4-port hub,CH334R,C4154405,QSOP-16-150mil,Extended,0.50,"Ports: 1=own MCU (internal FS) 2=left half 3=right half 4=spare"
 NUMPAD,Hub,Y2,1,12MHz crystal,X322512MSB4SI,C9002,SMD3225-4P,Basic,0.101,"CH334 has built-in load caps - verify internal value vs this 20pF CL crystal; fit DNF cap pads"
 NUMPAD,Hub,C12-C14,3,100nF 0402,CL05B104KO5NNNC,C1525,0402,Basic,0.006,"hub decoupling"
@@ -37,6 +37,6 @@ NUMPAD,SBU,-,-,SBU PASS-THROUGH,-,-,-,-,0.00,"*** Passive trace *** Tie SBU1+SBU
 NUMPAD,SBU,D-ESD2,2,ESD 5V bidirectional,PESD5V0S1BA,C2827694,SOD-323,Extended,0.036,"One per half-port SBU net"
 HALF-L,Switches,SW-,34,MX hotswap socket,CPG151101S11,C41430893,SMD 14.5x5.9mm,Extended,0.037,"BOTTOM SIDE. Alt: C49352235"
 HALF-R,Switches,SW-,41,MX hotswap socket,CPG151101S11,C41430893,SMD 14.5x5.9mm,Extended,0.037,"BOTTOM SIDE. Alt: C49352235"
-NUMPAD,Switches,SW-,25,MX hotswap socket,CPG151101S11,C41430893,SMD 14.5x5.9mm,Extended,0.037,"One per key. BOTTOM SIDE"
+NUMPAD,Switches,SW-,26,MX hotswap socket,CPG151101S11,C41430893,SMD 14.5x5.9mm,Extended,0.037,"One per key. BOTTOM SIDE"
 NOTE,Assembly,-,-,SINGLE-SIDED,-,-,-,-,-,"Put ALL SMD on the BOTTOM: sockets, MCU, passives, diodes, and any reverse-mount SK6812MINI-E. Top face bare except switch holes. Keeps JLC to one assembly pass"
 NOTE,Mechanical,-,-,PLATE REQUIRED,-,-,-,-,-,"Hotswap needs a switch plate or socket pads tear off during switch insertion. FR4 plate = just another JLC board"

Documents/numpad-layout.svg

@@ -16,11 +16,12 @@
 <title>Numpad — no encoder, nav shifted up</title>
 <desc>The volume encoder is gone. Home, End, Page Up, Page Down and Delete all move up one row, leaving a gap above the up arrow that separates the nav block from the arrow cluster.</desc>
 <text class="th" x="18" y="24">Numpad &#8212; settled layout</text>
-<text class="ts" x="18" y="44">25 keys, six columns by five rows. Nav block up top, isolated inverted-T, Enter and + on the thumb.</text>
+<text class="ts" x="18" y="44">26 keys. The nav block is now a solid 3&#215;2, with the arrows isolated by a symmetric pair of gaps.</text>
 <g class="c-teal"><rect x="148" y="88" width="58" height="58" rx="4"/><text class="ts" x="177" y="121" text-anchor="middle">Home</text></g>
 <g class="c-teal"><rect x="212" y="88" width="58" height="58" rx="4"/><text class="ts" x="241" y="121" text-anchor="middle">End</text></g>
 <g class="c-teal"><rect x="276" y="88" width="58" height="58" rx="4"/><text class="ts" x="305" y="121" text-anchor="middle">PgUp</text></g>
 <g class="c-teal"><rect x="148" y="152" width="58" height="58" rx="4"/><text class="ts" x="177" y="185" text-anchor="middle">Del</text></g>
+<g class="c-teal"><rect x="212" y="152" width="58" height="58" rx="4"/><text class="ts" x="241" y="185" text-anchor="middle">PrtSc</text></g>
 <g class="c-teal"><rect x="276" y="152" width="58" height="58" rx="4"/><text class="ts" x="305" y="185" text-anchor="middle">PgDn</text></g>
 <g class="c-teal"><rect x="212" y="216" width="58" height="58" rx="4"/><text class="ts" x="241" y="249" text-anchor="middle">↑</text></g>
 <g class="c-teal"><rect x="148" y="280" width="58" height="58" rx="4"/><text class="ts" x="177" y="313" text-anchor="middle">←</text></g>
@@ -43,10 +44,10 @@
 <g class="c-purple"><rect x="148" y="363" width="122" height="58" rx="4"/><text class="ts" x="209" y="396" text-anchor="middle">Enter</text></g>
 <g class="c-purple"><rect x="276" y="373" width="58" height="58" rx="4"/><text class="ts" x="305" y="406" text-anchor="middle">+</text></g>
 <g class="c-teal"><rect x="18" y="466" width="13" height="13" rx="3"/></g>
-<text class="ts" x="37" y="476">Nav &#183; 9</text>
+<text class="ts" x="37" y="476">Nav &#183; 10</text>
 <g class="c-coral"><rect x="188" y="466" width="13" height="13" rx="3"/></g>
 <text class="ts" x="207" y="476">Numpad &#183; 14</text>
 <g class="c-purple"><rect x="358" y="466" width="13" height="13" rx="3"/></g>
 <text class="ts" x="377" y="476">Thumb &#183; 2</text>
-<text class="ts" x="18" y="506">About 114 by 105 mm. The thumb pair spans exactly the three nav columns; three cells empty around the arrows.</text>
+<text class="ts" x="18" y="506">About 114 by 105 mm. Only two cells empty now, sitting symmetrically either side of the up arrow.</text>
 </svg>

README.md

@@ -41,16 +41,19 @@ either.
 |---|---|---|---|
 | `Schematics/Left`   | 1 | **34** | MCU, matrix, USB-C, SBU split link |
 | `Schematics/Right`  | 1 | **41** | MCU, matrix, USB-C, SBU split link |
-| `Schematics/Numpad` | 1 | **25** (14 numpad + 9 nav + 2 thumb) | MCU, matrix, **CH334R hub**, 3 downstream ports |
+| `Schematics/Numpad` | 1 | **26** (14 numpad + 10 nav + 2 thumb) | MCU, matrix, **CH334R hub**, 3 downstream ports |
 
 **Numpad layout is settled** — see `Documents/numpad-layout.svg`, and
 `Documents/three-board-overview.svg` for all three at the same scale. Six
-columns by five rows, ~114 × 105 mm, **25 keys and no encoder**.
+columns by five rows, ~114 × 105 mm, **26 keys and no encoder**.
 
-- **Nav block across the top**: Home/End/PgUp over Del/PgDn, with the arrows in
-  a standard **inverted-T** isolated below by three empty cells — the same
-  breathing room a 104 gives them. Del sits two rows above `←` with a gap
-  between, so the destructive key is never adjacent to the one you hit blind.
+- **Nav block across the top**: a solid 3×2 — Home/End/PgUp over Del/PrtSc/PgDn
+  — with the arrows in a standard **inverted-T** isolated below by a symmetric
+  pair of empty cells, the same breathing room a 104 gives them. Del sits two
+  rows above `←` with a gap between, so the destructive key is never adjacent to
+  the one you hit blind.
+- **PrtSc has a real key.** It's the screenshot key on every Linux desktop, so
+  it earns one. Insert, ScrLk and Pause do not, and stay on a layer.
 - **Numpad on the right**: digits in a 3×3 with `0` as a 2u, and `/ * −` in a
   right-hand column beside 9/6/3, where a full-size numpad puts its operators.
 - **`Enter` (2u) and `+` on a stepped thumb cluster**, spanning exactly the
@@ -61,7 +64,7 @@ columns by five rows, ~114 × 105 mm, **25 keys and no encoder**.
 - **No encoder.** Dropped along with the scroll wheel; volume lives on a layer
   or on the halves' function row. This makes the numpad a completely plain QMK
   keyboard — no encoder, no pointing device, just a matrix. It is the simplest
-  of the three boards by a distance, and ~$4.11 in parts.
+  of the three boards by a distance, and ~$4.16 in parts.
 
 Cabling: