> How do you do that cheapo upgrade? The chips on the 256K RAM expansion have all their pins connected to the same signals as the 256K RAM chips on the SAM mainboard - all except for one signal (I think - /CAS). So the simple way to double your RAM is to solder one 256K x 4-bit chip on top of each of the chips on SAM's motherboard, all except for the one odd pin which you poke out sideways and take to a pad on the motherboard using a short length of wire.
I'll try and remember to check the details in the technical manual tonight - it might actually be two signals, but I think it's just /RAS. It did occur to me that this techniques might actually be an easy way to add a megabyte to your SAM - pile up a load on chips and provide a small out port to bank between chips for the top 256K. There's no need to worry about refresh logic or multiplexing of address lines as the ASIC takes care of it all..... though the megabyte wouldn't be compatible the the existing megabyte (and hence wouldn't work in MasterDos). Andy ps: are people genuinely interested in connecting an SAA1099 to the PC to help with emulation, as someone suggested? It would be really quite easy using the printer port, and the sound could be fed into the line-in on a sound card. The only problem is the shortage of SAA1099's, and people would have to take soldering irons to their SAMs....
