< but it was a particularly twisted architecture that only a TRW satellit < programmer could love. An aside to all this... The 1802 was a very strange chip. It was by far the crudest and yet the easiest to program all at once. My pet peve is there are holes in the instruction set where a reciprocal instruction would have been nice but wasn't there. It redeeming feature was it was CMOS and the only other CMOS part at that time was the 6100 (PDP-8). What surprized me is that the 1802 (maybe the 05 too?) are still available. The 05 is desireable as it has the hard coded SCRT instuction (more like a procedure!). Allison