Z80 TRAP and CP/M

On 4/4/2006 at 10:07 AM Don Y wrote: Hmmm--I've got a couple of the 3870s and I don't believe they're of the same 8080/Z80 family. IIRC, the original F8 (the 3850) was not a complete microprocess and required one of several support chips that provided, among other things, the program counter and memory control logic. (3851, 3852, 3853?) Fairchild later introduced the 3859, which combined the two simplest chips (3850, 3851), but Mostek did them one better and combined the 3850 and one of the more complex support chips--I forget which one; it may have been the 3856. Again, IIRC (I had only peripheral experience with the things), the big advantage of the 3870 wasn't the level of integration, but the steeply lower ROM mask charge over the Fairchild parts. I believe that Fairchild, knowing a good thing when they saw it, licensed the 3870 I've got a bunch of the 2.5 MHz NSC800's--I'd love to get my hands on a 4 MHz part. NSC's part suffix numbering system is a bit bizarre and probably points to a story of a missed objective. The -1 is a 1 MHz part, but the -3 is 2.5 MHz; the -35 is 3.5 MHz and the -4 is 4 MHz. Cheers, Chuck