Alphatronic P2
Logic description
Overall description
The Triumph-Adler Alphatronic P2 divides its memory in two regions: the first quarter, where ROM, minimal system RAM and video RAM are located and the remaining 48KB, where RAM resides. In the case of the P2U models, a 16KB long pageable segment can be overlaid over the ROM and video area. This arrangement, however keeps the system paging frequently because it also replaces the VRAM.
In the first quarter, the first 6KB are ROM and there resides MOS (Micro Operating System) which is an interactive monitor that allows the setting of values into RAM or I/O as well as block commands. It was improved in P2U systems to take advantage over the additional 16KB RAM. There is also 1KB of static RAM following the ROM, which is used for the monitor; after the system RAM, there is a 1KB gap. The VRAM occupies the remaining memory of the page, although only the first 2KB are populated and the rest cannot be used by the video subsystem.
Units in collection
| ID | Model | Comments |
|---|---|---|
| 39 | Alphatronic P2U | Spanish variant |
| 42 | Alphatronic P2 | Italian variant |