---
title: "Creating a Four Port Expansion Decoder"
type: "article"
slug: "creating-a-four-port-expansion-decoder"
url: "http://localhost/article/creating-a-four-port-expansion-decoder/"
markdown_url: "http://localhost/article/creating-a-four-port-expansion-decoder.md"
published_at: "2020-10-27T17:10:11+00:00"
modified_at: "2024-05-26T14:34:46+00:00"
featured_image:
  url: "http://localhost/wp-content/uploads/2022/04/20230809-041332.jpg"
excerpt: "Memory-mapped IO for the 1000 computer."
category:
  - name: "Time Designs Magazine"
    slug: "time-designs"
    taxonomy: "category"
    url: "http://localhost/category/periodicals/time-designs/"
post_tag:
  - name: "Hardware project"
    slug: "hardware-project"
    taxonomy: "post_tag"
    url: "http://localhost/tag/hardware-project/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
  - name: "ZX81"
    slug: "zx81"
    taxonomy: "post_tag"
    url: "http://localhost/tag/zx81/"
model:
  - name: "Sinclair ZX81"
    slug: "zx81"
    taxonomy: "model"
    url: "http://localhost/model/zx81/"
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
indiv:
  - name: "Ed Fry"
    slug: "ed-fry"
    taxonomy: "indiv"
    url: "http://localhost/indiv/ed-fry/"
publication: "Time Designs Magazine"
publication_r:
  id: 10277
  title: "Time Designs Magazine"
  type: "periodical"
  url: "http://localhost/periodical/time-designs-magazine/"
authors: "Ed Fry"
volume: "4"
issue: "6"
issues_articles:
  - id: 26789
    title: "Time Designs Magazine v4 n6"
    type: "issue"
    url: "http://localhost/issue/time-designs-magazine-v4-n6/"
pages: "22-26"
pubdate: "September/October 1988"
archive_link: false
volumeissue: "v4n6"
---

# Creating a Four Port Expansion Decoder

Memory-mapped IO for the 1000 computer.