Not as a verified upgrade for a stock Atari 600XL or 800XL. Atari planned a 1090XL expansion chassis for XL computers and a Zilog Z80 CP/M card called the 1066, but the original system never reached retail. The Atari Museum says the 1066 has not been tested because its software drivers have not been found. A modern manual describes a remake card design, but does not establish a currently available, tested setup.
What the 1090XL and 1066 were designed to do
The 1090XL was a planned modular expansion system that connected to an Atari XL computer through its Parallel Bus Interface (PBI). Its chassis was designed with five 8-bit PBI slots for expansion cards, including memory, 80-column video, input/output, home-automation and prototyping options. One proposed card would add a Z80 processor for CP/M. The Atari Museum’s 1090XL overview also describes a bus-mastering control line intended to let an alternate-CPU card take control of the computer’s bus.
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The Z80 board planned for the 1090XL was designated the Atari 1066. It was distinct from the Atari 1060 CP/M Add-on, also known as Sweet-Pea, which was conceived as a separate external unit. Atari’s 8-bit FAQ says the 1060 was shown at the June 1983 Consumer Electronics Show and was planned around a 4 MHz Z-80A, 64 KiB of RAM, CP/M 2.2 and 80-column display capability. Atari confirmed the 1060’s cancellation in January 1984; it did not ship. The Atarimania FAQ also describes the 1090XL as never shipped.
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What is—and is not—known about CP/M on the 1066
The Atari Museum’s 1066 card page identifies a Zilog Z-80 processor and support circuitry, but says the board has not been tested because software drivers have not been found. The page reports that CP/M was expected to work with the 80-column card for an 80-column display; that is a reported design expectation, not proof of a working system.
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So the idea was to let an Atari XL computer use CP/M through an alternate Z80 processor, with the 1090XL providing the expansion chassis and the 1066 supplying the processor card. The available historical evidence does not show that Atari owners could buy and install this as a retail upgrade, or that the original hardware ran CP/M successfully.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What the modern remake manual describes
A modern 1090XL expansion-card manual describes a Z-80 CP/M card with a Z-80 CPU and 64 KiB of RAM for that processor. It says the card needs a CP/M boot disk containing software to use Atari I/O as well as the operating system; without that disk, the card remains dormant.
This manual documents a remake design, not proof that a complete system is currently sold or has been tested in a particular 600XL or 800XL configuration. Its remake-specific details should not automatically be treated as specifications for the original 1066 prototype.
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How the two Atari CP/M concepts differ
| System | Form and dependency | Planned CP/M capability | Evidence status |
|---|---|---|---|
| 1060 / Sweet-Pea | Separate external add-on for an Atari 8-bit computer. | The Atarimania FAQ describes a planned 4 MHz Z-80A, 64 KiB RAM, CP/M 2.2 and 80-column display capability. | Atari cancelled it before shipment; the FAQ says it did not ship. Atarimania FAQ |
| 1090XL with 1066 | PBI expansion card that depended on the 1090XL chassis. | Z80-based CP/M was a planned card capability. A modern remake manual describes 64 KiB of RAM for the Z-80 and a boot disk with Atari I/O software. | The original 1090XL did not reach retail, and the Atari Museum says the 1066 has not been tested because drivers were not found. The manual does not establish current availability or successful operation. Atari Museum overview; Atari Museum 1066 page; modern manual |
What an Atari XL owner can conclude
- The 1090XL was a proposed five-slot PBI expansion chassis, not a documented retail accessory owners could simply add to a stock 600XL or 800XL.
- The 1066 was the intended Z80 CP/M card for that chassis; the 1060 was a separate external CP/M concept.
- CP/M support was the design goal, but the cited historical documentation does not establish a tested original 1066 system.
- The modern manual gives requirements for a remake design, including a CP/M boot disk with Atari I/O software, but it does not verify a purchasable or operational kit.
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