On Wed, 4 Mar 1998, Mike Keitz wrote: > On Wed, 4 Mar 1998 13:33:52 +0200 Pasi T Mustalahti > writes: > >PTM: If you have a project somewhat critical of pins, you could do > >like > >this: > > > > pic PA0 |-----res--| counter > > PA1 |-----up---| > > PA2 |--R/W-- |____________________________ > > | | | |||||| > > | | A0 A1..A15 > > | | | |||||| > > | --------x--|-------- |||||| > > | | | | |||||| > > PB0 |--D0/D4-----| 2x4bit |--D0--| > > PB1 |--D1/D5-----| tri-state |--D1--| SRAM > > PB2 |--D2/D6-----| buffer |--D2--| > > PB3 |--D3/D7-----| ... |--D7--| > > > >You write and read the data hinible + lonible. Counter gives you A0 to > >select HI, LO. PTM: Someone asked me to make some coerrections, so I made the them in the picture above. I'll add the missing R/W- and data-lines (latch-RAM) > I assume the "tri-state buffer" is a 4-channel 1-2 analog multiplexer. PTM: I used more than one chip here where there stands 'buffer' That anal-mux might give some advance. > A certain chip maker really, really, needs to make a PIC with about > 2Kbyte of RAM in it. PTM: In normal sittuations I I'm either satisfied with 10-20B of RAM or I need it so much that there is no possibilities to integrate it in the sama chip in todays technology. -------------------------------------------------------------------------- PTM, pasi.mustalahti@utu.fi, ptmusta@utu.fi, http://www.utu.fi/~ptmusta Lab.ins. (mikrotuki) ATK-keskus/Mat.Luon.Tdk OH1HEK Lab.engineer (PC support) Computer Center OI7234 Mail: Turun Yliopisto / Fysla, Vesilinnantie 5, 20014 Pt 02-3336669, FAX 02-3335632 (Pk 02-2387010, NMT 049-555577) --------------------------------------------------------------------------