---
title: "Timer in Assembly"
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published_at: "2025-07-12T01:36:30+00:00"
modified_at: "2025-07-12T01:36:30+00:00"
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excerpt: "While working on a game project, I needed a way to time what a user was doing, all in Z80 assembly. The ZX81 does not have a clock mechanism, but it has something close."
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pages: "19-20"
pubdate: "January 2025"
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---

# Timer in Assembly

While working on a game project, I needed a way to time what a user was doing, all in Z80 assembly. The ZX81 does not have a clock mechanism, but it has something close.