Apple S1

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<div style="font: bold 2em/1.2 -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Helvetica Neue', Helvetica, Arial, sans-serif; color: var(--wiki-color);">Apple S1</div>
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! class="ios-lab" | Designer
| class="ios-val" | [[Apple]]
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! class="ios-lab" | Introduced
| class="ios-val" | April 2015 (Apple Watch, 1st generation)
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! class="ios-lab" | Type
| class="ios-val" | System in Package (SiP)
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! class="ios-lab" | CPU
| class="ios-val" | Single-core, 520 MHz (32-bit)
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! class="ios-lab" | Devices
| class="ios-val" | Apple Watch (1st generation)
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! class="ios-lab" | Successor
| class="ios-val" | [[Apple S1P]] · [[Apple S2]]
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The Apple S1 launched the S series in the original Apple Watch in April 2015 — not a chip but a complete computer sealed into a single resin-encapsulated package: processor, memory, storage, sensors, and wireless, about thirty components in the space of a fingertip. The System-in-Package construction protected the electronics from water and dust and set the physical format every Apple Watch has used since.

= Legacy =

The S1's single 32-bit core was modest — the original Watch leaned on a paired [[iPhone]] for nearly everything — but the SiP idea it introduced became the S series itself. The first-generation Watch ended its software life at watchOS 4, the shortest run of any model.