Hi Martin, I see what you are saying. I guess I was hoping for some more details documented somewhere. The disassembled ROM file has helped shed more details on the whole paging method for code to appear in the 256-byte window. I'll keep tinkering.
Thanks, - Peter On Mon, Nov 24, 2025 at 6:44 AM Martin Bishop < [email protected]> wrote: > Hi Peter > > The TM section (4.11) on the read-write register looks to me like a > comprehensive descrioption of it's functionality; esp if read with an LS299 > data sheet. There may be second order points which study of the > maintenance (schematic) prints will reveal - but I would be surprised, this > is intened to be vanilla. > > The (useful) student guide you identified gives a good precis of R/W > register function on page BD-15ff. The R/W register looks like a 16 bit > register, writable at byte granularity for testing / exercising minimal > systems. Very useful for low level diagnostics / faultfinding of DATI DATO > DATOB bus cycles. > > HtH; Martin > > -----Original Message----- > From: Peter Ekstrom via cctalk <[email protected]> > Sent: 23 November 2025 16:52 > To: General Discussion: On-Topic and Off-Topic Posts < > [email protected]> > Cc: Peter Ekstrom <[email protected]> > Subject: [cctalk] Re: BDV11 programming information > > Hi Glen, > > Yes, and I have looked over it several times. It does have quite a bit of > info, but it doesn't go into much detail for the R/W register. > I also found a student guide that includes the BDV11 and it help shed some > light on how the code in the ROMs is segmented. > It helped me visualize more how it is done. But I am still missing things > like the details for the R/W register. > > > https://wwcm.synology.me/pdf/EY-DX056-SP-002&J6269-A&EY-DX052-SG-002%20Small%20Systems%20Training%20PDP-11V23-&%2011T23%20System%20Maintenance%20Student%20Guide.pdf > > - Peter > > > On Sun, Nov 23, 2025 at 10:52 AM Glen Slick via cctalk < > [email protected]> wrote: > > > On Sun, Nov 23, 2025, 6:32 AM Peter Ekstrom via cctalk < > > [email protected]> wrote: > > > > > Does anyone know if there is any programming information about the > > > BDV11 card? > > > I have disassembled the ROM files for it and I see they do various > > > operations with the registers on the card, but it is not clear to me > > > exactly what they are doing. > > > > > > - Peter > > > > > > > Did you already find this? > > > > http://www.bitsavers.org/pdf/dec/qbus/EK-BDV11-TM-001_Mar78.pdf > > > > > > > >
