Timeline for How did 2-chip CPUs work?
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 20, 2020 at 22:54 | comment | added | supercat | @DrSheldon: The 180x family was based on FRED, but the first products in the family were the two halves of the 1801. | |
| Nov 20, 2020 at 22:51 | comment | added | supercat | ...the behavior of the register/addressing unit, since it would seem like it could be a useful component for a fair number of purposes requiring a moderate-sized register file. | |
| Nov 20, 2020 at 22:50 | comment | added | supercat | I just found a data sheet for the 1801 at datasheets.pl/elementy_czynne/IC/CDP1801.pdf and it looks as though the boundary is drawn slightly differently from what I would have guessed, in a manner that requires a few more inter-chip connections. From what I can tell, all listed 1801 opcodes behave identically in the 1802, though some 1802 opcodes, including rather bizarrely "load without incrementing address" are missing in the 1801. Given that there are seven interconnects with undocumented functionality plus TPB, I wonder if it might have been worth documenting... | |
| Nov 20, 2020 at 22:38 | comment | added | DrSheldon | Actually -- according to its Wikipedia page -- the 1802 was based on an earlier design called FRED, which was built from discrete TTL chips. | |
| Nov 20, 2020 at 18:48 | comment | added | supercat | @MichaelGraf: Do you like my edit? | |
| Nov 20, 2020 at 18:48 | history | edited | supercat | CC BY-SA 4.0 |
added 105 characters in body
|
| Nov 20, 2020 at 18:11 | comment | added | Michael Graf | I don't know, to be honest, I just remembered that it was based on an earlier two chip CPU, not how that old CPU worked. But it's very plausible. | |
| Nov 20, 2020 at 16:39 | comment | added | supercat | @MichaelGraf: So I guess I not only answered the question of how a two-chip CPU could work, but how one actually did? | |
| Nov 20, 2020 at 7:07 | comment | added | Michael Graf | The CDP1802 is like that because it's based on the two-chip CDP1801R and CDP1801U. See en.wikipedia.org/wiki/RCA_1802, and the sources linked to there. | |
| Nov 20, 2020 at 0:15 | history | answered | supercat | CC BY-SA 4.0 |