Posted By
Litwr on 2016-09-25 23:34:55
| Re: What would I do differently in the Plus/4
[z80] 1.3 MHz for CPU + 1.4 MHz for video (Amstrad PCW uses 720x256 video and was cheap) = 2.7 MHz. RAM used always are with the higher limits, for example, 3 MHz. BBC Micro was at 1981 and has a lot of other expensive parts : 4 ADC, TUBE interface, 2 video chips, ... C+4 was at 1984 when DRAM were much cheaper. For example, VIC-20 of 1981 uses SRAM (!) because it was cheaper at 1981... I'm almost sure if we would have more enthusiastic experts in electronics then we had C+4 at 3.5 MHz like mentioned C64 project. However it is just hypothesis... Do you mean 6509 from CBM II? It has the same commands as 6502 plus 2 additional instructions to work with 1 MB address space. It is interesting why 2 MHz 6502 almost completely missed US market (BBC Micro, CBM II, Apple III)? Tandy Color was underclocked...
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