| ??? 11/13/08 01:30 Read: times |
#160001 - pDATA? Responding to: ???'s previous message |
Andy Neil said:
Richard Erlacher said:
What's the "best", or at least generally accepted, way to describe all these various forms of read/write memory unambiguously? I think the way Erik said is the most widespread? viz: Note that DATA overlays the first 128 bytes of IDATA, and PDATA overlays 256 bytes of XDATA. The terms "internal" and "external" are essentially meaningless these days (or, at best, their meanings are purely historical). Until they actually put a significant amount of xRAM on-chip, external will continue to have meaning beyond the historical. I'd guess that 64KB of SRAM would do, for starters, but it would have to have external access as well as internal, since not everything happens on chip. BTW, isn't what you describe as "pDATA" exactly the same as "xDATA", with the only distinction being that it is accessible via the DPTR as well as R0/R1? Which devices have that construct on-chip? Is that memory like the 1 kB of xRAM on the Maxim/Dallas DS89C4x0's? I presently use the falling edge of P2.7 during ALE to increment a programmable counter that provides the additional addresses I need for a data buffer of moderate (320 k-bytes, in this case) size. Until they find a way to put, say, 64 TB or so of ram on a chip, someone will always complain that he needs "more core." RE |
