On 2010 Sep 6, at 5:56 AM, allison wrote: OK, a family I had never run across before. Found a datasheet for (by appearance) a descendant (D75112/6). Looks like they took a cue from the 8080 family - the register set is nearly identical but in 4 bits, with register pairs BC, DE, HL to make 8-bit registers.

I think I have the NEC databook containing the series. Do you need a scan?

On Mon, Sep 6, 2010 at 5:13 PM, allison <ajp166 at verizon.net> wrote: > On 09/06/2010 02:34 PM, Brent Hilpert wrote: >> >> On 2010 Sep 6, at 5:56 AM, allison wrote: >> >>> On 09/05/2010 10:06 PM, Brent Hilpert wrote: >>>> >>>> I just ran across an NEC D75008 microcontroller in a small photo >>>> copier >>>> ca. 1990. According to a search it is a 4-bit microcontroller. >>>> >>>> Idle curiousity, but does anybody know if this has any inheritance >>>> from >>>> or relation to better-known microcontrollers such as the TMS1000, >>>> that is, >>>> is it NEC's version of something better known?, or is it NEC's own >>>> architecture? >> >>> No, ?it is NEC unique. ?For 4 bitters that is usually the case. ? >>> it is a >>> much more expanded >>> design closer to modern PICs with many variants having LCD driver on >>> board. >> >> OK, a family I had never run across before. Found a datasheet for (by >> appearance) a descendant (D75112/6). Looks like they took a cue from >> the >> 8080 family - the register set is nearly identical but in 4 bits, >> with >> register pairs BC, DE, HL to make 8-bit registers. >> > > Many of the 4bit MCUs did that. ?The instruction set is is similar to > 8080 > and different since it has > skip on condition and typical Harvard oddities and additions for > tables and > inline constants. > > The family closest to it is the 1980s ucom75.