From a0a42cd84e4aec42f97cba849683cab5d49de4e1 Mon Sep 17 00:00:00 2001
From: Denis Chevalier <perso@denischevalier.fr>
Date: Mon, 10 Aug 2026 16:21:38 +0200
Subject: generate figure 1 (db-25 backplane connector) using cetz

---
 electrical-specifications.typ | 127 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 124 insertions(+), 3 deletions(-)

(limited to 'electrical-specifications.typ')

diff --git a/electrical-specifications.typ b/electrical-specifications.typ
index 320ec1e..2a9ec15 100644
--- a/electrical-specifications.typ
+++ b/electrical-specifications.typ
@@ -1,4 +1,5 @@
 #import "lib/unify.typ": qty, qtyrange
+#import "@preview/cetz:0.5.2"
 
 = Electrical specifications <electrical-specifications>
 
@@ -573,9 +574,129 @@ the cassette to the power distribution board. D-sub connectors are ubiquitous,
 sturdy and shielded.
 
 #figure(
-  image("pictures/db-25-backplane-connector.svg"),
-  caption: [DB-25 backplane connector],
-) <figure-backplane-connector>
+  cetz.canvas({
+    import cetz.draw: *
+
+    let dx = 1.0
+    let top-y = 0.55
+    let bot-y = -0.55
+
+    // Outer mounting flange / metal ears
+    rect(
+      (-2.0, -1.4),
+      (14.0, 1.4),
+      rx: 0.2,
+      fill: luma(245),
+      stroke: 1pt + luma(100),
+    )
+
+    // Left and right chassis mounting screw holes
+    circle((-1.3, 0), radius: 0.35, fill: luma(220), stroke: 1pt + luma(120))
+    circle((-1.3, 0), radius: 0.20, fill: white, stroke: 0.8pt + luma(100))
+    circle((13.3, 0), radius: 0.35, fill: luma(220), stroke: 1pt + luma(120))
+    circle((13.3, 0), radius: 0.20, fill: white, stroke: 0.8pt + luma(100))
+
+    // D-Sub trapezoidal shroud outline
+    line(
+      (-0.7, 1.15),
+      (12.7, 1.15),
+      (12.2, -1.15),
+      (-0.2, -1.15),
+      close: true,
+      fill: luma(230),
+      stroke: 1.5pt + black,
+    )
+
+    // Shell Earth ground connection reference
+    line((-0.45, -1.15), (-0.45, -2.0), stroke: (
+      paint: luma(120),
+      thickness: 0.7pt,
+      dash: "dashed",
+    ))
+    content(
+      (-0.45, -2.05),
+      text(size: 7.5pt, weight: "bold")[Shell: Chassis Earth],
+      angle: -50deg,
+      anchor: "north-west",
+    )
+
+    // Top row pins (Pins 1 to 13)
+    let top-pins = (
+      ("1", [$plus qty(15.00, "V")$]),
+      ("2", [$plus qty(15.00, "V")$]),
+      ("3", [$qty(-15.00, "V")$]),
+      ("4", [$qty(-15.00, "V")$]),
+      ("5", [AGND]),
+      ("6", [AGND]),
+      ("7", [AGND]),
+      ("8", [$plus qty(10.0000, "V")$ Force]),
+      ("9", [$plus qty(10.0000, "V")$ Sense]),
+      ("10", [$qty(-10.0000, "V")$ Force]),
+      ("11", [$qty(-10.0000, "V")$ Sense]),
+      ("12", [AGND]),
+      ("13", [AGND]),
+    )
+
+    // Bottom row pins (Pins 14 to 25)
+    let bot-pins = (
+      ("14", [AGND]),
+      ("15", [AGND]),
+      ("16", [AGND]),
+      ("17", [DGND]),
+      ("18", [DGND]),
+      ("19", [$plus qty(5.0, "VD")$]),
+      ("20", [$qty(-5.0, "VD")$]),
+      ("21", [Stagger]),
+      ("22", [_Reserved_]),
+      ("23", [_Reserved_]),
+      ("24", [_Reserved_]),
+      ("25", [Chassis Earth]),
+    )
+
+    // Draw Top Pins (1-13)
+    for (i, p) in top-pins.enumerate() {
+      let x = i * dx
+      let p-num = p.at(0)
+      let p-sig = p.at(1)
+
+      circle((x, top-y), radius: 0.26, fill: white, stroke: 1pt + black)
+      content((x, top-y), text(size: 7pt, weight: "bold")[#p-num])
+
+      line((x, top-y + 0.26), (x, 1.8), stroke: (
+        paint: luma(120),
+        thickness: 0.6pt,
+      ))
+      content(
+        (x, 1.85),
+        text(size: 7.5pt)[#p-sig],
+        angle: 50deg,
+        anchor: "south-west",
+      )
+    }
+
+    // Draw Bottom Pins (14-25)
+    for (j, p) in bot-pins.enumerate() {
+      let x = (j + 0.5) * dx
+      let p-num = p.at(0)
+      let p-sig = p.at(1)
+
+      circle((x, bot-y), radius: 0.26, fill: white, stroke: 1pt + black)
+      content((x, bot-y), text(size: 7pt, weight: "bold")[#p-num])
+
+      line((x, bot-y - 0.26), (x, -1.8), stroke: (
+        paint: luma(120),
+        thickness: 0.6pt,
+      ))
+      content(
+        (x, -1.85),
+        text(size: 7.5pt)[#p-sig],
+        angle: -50deg,
+        anchor: "north-west",
+      )
+    }
+  }),
+  caption: [DB-25 backplane connector physical pinout and signal allocation diagram.],
+) <figure-backplane-connector-diagram>
 
 #figure(
   table(
-- 
cgit