On 11/5/15 6:57 PM, Al Kossow wrote: I was wondering about software. Is anyone planning to turn those schematics into verilog? If they are, and they want help, let me know... -brad

On 09.11.2015 15:11, Al Kossow wrote: Are the system MICROM's already read out ? Furthermore there seems to have been variants of the Microengine with and without the interrupt priority encoder.( WD2083-U04 ) Anyone aware of these variants ? Jos

On Mon, Nov 9, 2015 at 7:04 AM, Brad Parker <brad at heeltoe.com> wrote: I'm working on dumping the microcode. The CP2161 control chip and CP2171-nn microms are probably the same as the corresponding CP1621/CP1661 and CP1631-nn, respectively, other than the PLA contents in the control chip and the ROM contents of the microms. The "control" chip PLAs are involved in macroinstruction decode and microinstruction sequencing, and there is no known way to dump them electrically, so as Al mentioned, a friend had photomicrographs of that chip made. We may need photomicrographs of the CP2161 (LSI-11) and/or CP1661 (WD-16, Alpha Micro AM100) for comparison. A low-resolution photomicrograph of the CP2161 is already online, but higher resolution is needed to resolve PLA contents. There is evidence that the data path chip, CP2151, is interchangeable with the CP1611 data path chip used in the LSI-11 and WD16. The microarchitecture, including the microinstruction set, is documented in the DEC LSI-11 WCS User's Guide, EK-KUV11-TM-001, (available on Bitsavers). Note that some details in that manual, including the usage of microinstruction bus bits MIB<21:18>, are specific to how the chip set is used in the LSI-11, and are not applicable to the WD90 chipset. The WD9000 board contains one WD chip for which no documentation is available, the WD2083U-04. When I traced the signals it appeared to be a custom interrupt and DMA request prioritizer. That appears to be confirmed by the recently found WD9000 schematics (also on Bitsavers). I suspect that the WD2083 is a mask-programmed PLA. Other than the WD90 chipset and the WD2083, all of the chips on the WD900 board were readily commercially available and reasonably well documented.

On Mon, Nov 9, 2015 at 12:39 PM, Jos Dreesen <jos.dreesen at bluewin.ch> wrote: [about the WD2083U-04] Interesting. I'd never seen any official schematics before you posted yours, and apparently I don't have any early enough boards to have the Am25LS2513. I might at some point contrive a test fixture to verify the WD2083U-04 behavior against the Am25LS2513, to determine whether there are any changes. Since the AMD part was readily available at the time, and not expensive, I wouldn't have expected WD to design their own replacement unless they wanted to change the functionality. By the way, do you have sheet 5? No hurry, but it would be nice to see that too. Best regards, Eric

I wrote: The Am25LS2513 has no internal state (flip-flops), and most likely even if the WD2083U-04 has differences, it probably doesn't have internal state either. It should therefore be possible to wire it up to be read using an EPROM programmer, e.g., as a 27128. To account for the three-state control, it could be read twice, once with external pullups on the A outputs, and once with external pulldowns. The differences in the read data will show the three-state cases. I'm pretty busy at the moment, but I might have a go at that next week.

On Fri, 6 Nov 2015, Jos Dreesen wrote: Never had any problems with 8" BASF floppies (and 5?" BTW). Christian

On 11/5/15 9:06 PM, Jos Dreesen wrote: Yes. I was going to try what I use on one, white board cleaner. Chuck has not had good luck with BASF recovery.