Guessing Which Motorola Microcontroller Part It Is (6801/6805/68HC11/6809)

Wasted too much time on this. 

This is extracted from my response to a post to the Facebook vintage {Computers | Microprocessors | Microcontrollers} group, asking for help identifying a Motorolo-logo microcontroller found in a washing machine with an apparent custom SOC part number ZC85148L, with an apparent date stamp from early 1984. 

There were many guesses as to what the ZC85148 was, and I thought I'd put my guesses and reasoning out here, to make them more available for searching:

I'm guessing either 6805/68HC05 or 6801/68HC01.

6805 was essentially a stripped-down 6800, with only one eight-bit accumulator (A), one eight-bit index (X, yes, eight-bit), bit instructions, expanded indexed modes, better power-saving stuff, lots of timers, some analog-to-digital, and other integrated I/O to choose from. At least some parts included hardware 8-bit multiply.

6801/68HC01 was exactly the 6800 with a few new 16-bit instructions for the double accumulator A:B pair, better X handling, hardware 8-bit multiply, and better power-saving mode stuff.

My reasoning is as follows:

If the chip were a bare CPU, it would need separate ROM and RAM parts on the circuit board, and such were nowhere in evidence. From the late 1970s until Motorola spun off the microprocessors business and renamed it Freescale, they provided Systems-On-a-Chip (SOC) semi-custom microcontrollers which included RAM, ROM, and I/O on chip. It's a pretty safe bet that the part was an SOC microcontroller.

I am not aware of any 6809 SOC products from Motorola, so, since the circuit board showed no evidence of ROM or RAM, I'm pretty sure that it is not a 6809 variant of any sort. (If there were any special-order 6809 SOC microcontrollers, that would be interesting to hear about.) 

The 68HC11 did start shipping in 1984, so it could possibly be a 68HC11. 

(68HC11 is a 6801 in HCMOS, with an additional Y index register and a pre-byte that converts X-indexed op-codes to Y-indexed opcodes, plus hardware integer and fraction divide, bit instructions, and a little bit more. Some people confuse the 68HC11 with the 6809. I discussed the differences between the 68CH11 and the 6809, comparing their architecture and lineage, in another rant here, several years back: https://defining-computers.blogspot.com/2018/12/68hc11-is-not-modified-6809-and-what-if.html. There are a few errors there I need to go back and correct sometime, but they are not errors of substance, I think.)

I don't have solid information on when the first HC08 microcontrollers started shipping, but my impression is no sooner than the late 1980s. So  I'm guessing it was not an HC08 or HCS08 or any of the later extensions thereof. 

(HC08s were 68HC05s with a high-byte extension for the X register and some other useful stuff, including hardware 8-bit multiply and divide.)

Other possibilities -- I understand that Motorola did second-source at least one other company's CPU in the 1970s. Whether the Intel 8501 might have been one of those, well, it seems ludicrous, but I have some conflicting memories. I think they had mostly gotten out of that business by the mid-1980s

It is my memory that they dabbled in manufacturing IBM compatible desktop PCs in the mid-to-late 1980s, but I don't remember whether that included manufacturing their own 8086 compatible CPUs, or second-sourcing Intel's. Anyway, that ended up only for desktop, and management quickly recognized that business model was not going to be profitable for them (and had been a marketing misstep).

I did also see announcements and engineering materials for 6502 core SOCs from Motorola, somewhere around 1986 or '87, IIRC, but those also seemed to have been dropped pretty quickly. It would not have been there in 1984.

And it is also my understanding that Motorola provided manufacturing for some mil-std microcontrollers, but I think that was only to the military and maybe NASA. Those were 16-bit, and not based on any of the 68XX or 68XXX series. I suppose it would not be impossible to see something like that in a washing machine controller, but it would be overkill.

There were also 4-bit and 1-bit SOC microcontrollers that Motorola produced in the late 1970s, but I don't remember any of them in 40-pin dip. I think they would be a bit underpowered.

I don't think the 88000 RISC series was even announced yet in 1984, and the Power architecture discussions with IBM and Apple had not even been imagined yet. There was the one-off custom implementation of the 360 architecture borrowing from the 68000. We can be sure that none of these would have been in a 40-pin chip in a washer in 1984.

Which is why my guesses come down to the 6805/68HC05 or the 6801/68HC01.