8051, was Re: Editor religious wars (was Re: Museums)

Tony Duell wrote: The answer is, nay. As Tony said the 8050/40 is a version of the 8048/35 group that has 256bytes of internal ram and if rom is present 2k. FYI: 256 bytes is the addressing limit for ram in the part and the pointer register (R0, R1 or the secondaries are 8bit. 8048 is a 12bit max instruction address and 8bit data address Harvard machine. The code at the source level and be ported easily to 8051 if care is taken to limit interactions with the added features so notably the initialization code must be changed to reflect enviroment. The 8051 is a 16bit instruction address 16bit data address Harvard machine. The 8051 is very similar to 8048 in basic design but has greater addressing and larger instruction set. The 8051 also adds a significant number if internal peripherals that would require external chips in the 8048 design to approximate. NOTE: it is possible with a simple external hack (external rom and ram) to make both parts look like a VonNeuman like machine. It was a common hack to make instruction space and data space overlap. Allison