major improvements for soic sot236 footprints

README.md

@@ -96,14 +96,20 @@ industry best practices or otherwise "reasonable" defaults. In theory, upgrading
 footprinter could cause the defaults to change, which is why sloppy definitions
 are generally not desirable.
 
-## Adding new footprint functions
+An example of a sloppy definition is `bga64`. It's very underconstrained and
+unlikely to be correct (what's the pitch? pad size?). tscircuit strict mode
+or a linter will eventually error if it sees these.
+
+## Adding a new footprint function
 
-You can add new footprint functions by introducing a new function in the [src/fn](https://github.com/tscircuit/footprinter/tree/main/src/fn)
-directory. You'll also need to export it from the [footprint function index file](https://github.com/tscircuit/footprinter/blob/main/src/fn/index.ts)
+You can add new footprint functions by introducing a new function in the [src/fn directory](https://github.com/tscircuit/footprinter/tree/main/src/fn). You'll also need to export it from the [footprint function index file](https://github.com/tscircuit/footprinter/blob/main/src/fn/index.ts)
 
 After you've written the function, you can introduce a quick test, e.g. [soic.test.ts](https://github.com/tscircuit/footprinter/blob/main/tests/soic.test.ts)
 Currently it's not possible to see if a given definition is sloppy.
 
-An example of a sloppy definition is `bga64`. It's very underconstrained and
-unlikely to be correct (what's the pitch? pad size?). tscircuit strict mode
-or a linter will eventually error if it sees these.
+To run tests, just run `npx ava ./tests/soic.test.ts` or whatever your test
+file is.
+
+You'll sometimes see this `logSoup` function- this makes some debug output
+appear at https://debug.tscircuit.com. Make sure to hit "pcb" and "pcb_renderer"
+after the design.

src/fn/soic.ts

@@ -6,15 +6,22 @@ import type { NowDefined } from "../helpers/zod/now-defined"
 import { u_curve } from "../helpers/u-curve"
 import { rectpad } from "src/helpers/rectpad"
 
-export const extendSoicDef = (newDefaults: { w?: string; p?: string }) =>
+export const extendSoicDef = (newDefaults: {
+  w?: string
+  p?: string
+  legsoutside?: boolean
+}) =>
   z
     .object({
-      soic: z.literal(true),
       num_pins: z.number(),
       w: length.default(length.parse(newDefaults.w ?? "5.3mm")),
       p: length.default(length.parse(newDefaults.p ?? "1.27mm")),
       pw: length.optional(),
       pl: length.optional(),
+      legsoutside: z
+        .boolean()
+        .optional()
+        .default(newDefaults.legsoutside ?? false),
     })
     .transform((v) => {
       // Default inner diameter and outer diameter
@@ -33,14 +40,17 @@ export const extendSoicDef = (newDefaults: { w?: string; p?: string }) =>
 const soic_def = extendSoicDef({})
 export type SoicInput = z.infer<typeof soic_def>
 
-export const getCcwSoicCoords = (
-  pinCount: number,
-  pn: number,
-  w: number,
+export const getCcwSoicCoords = (params: {
+  num_pins: number
+  pn: number
+  w: number
   p: number
-) => {
+  pl: number
+  legsoutside: boolean
+}) => {
+  const { num_pins, pn, w, p, pl, legsoutside } = params
   /** pin height */
-  const ph = pinCount / 2
+  const ph = num_pins / 2
   const isLeft = pn <= ph
 
   /** Number of gaps between pins on each side, e.g. 4 pins = 3 spaces */
@@ -51,13 +61,15 @@ export const getCcwSoicCoords = (
 
   const h = gs * leftPinGaps
 
+  const legoffset = legsoutside ? pl / 2 : -pl / 2
+
   if (isLeft) {
     // The y position starts at h/2, then goes down by gap size
     // for each pin
-    return { x: -w / 2, y: h / 2 - (pn - 1) * gs }
+    return { x: -w / 2 - legoffset, y: h / 2 - (pn - 1) * gs }
   } else {
     // The y position starts at -h/2, then goes up by gap size
-    return { x: w / 2, y: -h / 2 + (pn - ph - 1) * gs }
+    return { x: w / 2 + legoffset, y: -h / 2 + (pn - ph - 1) * gs }
   }
 }
 
@@ -78,18 +90,20 @@ export const soic = (raw_params: {
 export const soicWithoutParsing = (params: z.infer<typeof soic_def>) => {
   const pads: AnySoupElement[] = []
   for (let i = 0; i < params.num_pins; i++) {
-    const { x, y } = getCcwSoicCoords(
-      params.num_pins,
-      i + 1,
-      params.w,
-      params.p ?? 1.27
-    )
-    pads.push(rectpad(i + 1, x, y, params.pw ?? "0.6mm", params.pl ?? "1mm"))
+    const { x, y } = getCcwSoicCoords({
+      num_pins: params.num_pins,
+      pn: i + 1,
+      w: params.w,
+      p: params.p ?? 1.27,
+      pl: params.pl,
+      legsoutside: params.legsoutside,
+    })
+    pads.push(rectpad(i + 1, x, y, params.pl ?? "1mm", params.pw ?? "0.6mm"))
   }
 
   /** silkscreen width */
-  const sw = params.w - params.pw - 0.4
-  const sh = (params.num_pins / 2 - 1) * params.p + params.pl + 0.4
+  const sw = params.w - (params.legsoutside ? 0 : params.pl * 2) - 0.2
+  const sh = (params.num_pins / 2 - 1) * params.p + params.pw
   const silkscreenBorder: PcbSilkscreenPath = {
     layer: "top",
     pcb_component_id: "",

src/fn/sot236.ts

@@ -4,8 +4,9 @@ import type { z } from "zod"
 export const sot236_def = extendSoicDef({
   p: "0.95mm",
   w: "1.6mm",
+  legsoutside: true,
 })
 
 export const sot236 = (params: z.input<typeof sot236_def>) => {
-  return soicWithoutParsing(sot236_def.parse(params))
+  return soicWithoutParsing(sot236_def.parse({ ...params, num_pins: 6 }))
 }

tests/soic.test.ts

@@ -6,6 +6,6 @@ test("soic8_w5.3mm_p1.27mm", async (t) => {
   const { fp, logSoup } = await getTestFixture(t)
   const soup = fp.string("soic8_w5.3mm_p1.27mm").soup()
 
-  t.is(su(soup).pcb_plated_hole.list().length, 8)
+  t.is(su(soup).pcb_smtpad.list().length, 8)
   await logSoup(soup)
 })

tests/sot236.test.ts

@@ -0,0 +1,11 @@
+import test from "ava"
+import { getTestFixture } from "tests/fixtures/get-test-fixture"
+import { su } from "@tscircuit/soup-util"
+
+test("sot236", async (t) => {
+  const { fp, logSoup } = await getTestFixture(t)
+  const soup = fp.string("sot236").soup()
+
+  await logSoup(soup)
+  t.pass()
+})