Hi Jay, Thank you for this information! I didn't think of trying that. Paul's suggestion to set PSW to 340 and a reset works as well. But it is good to have more options. :) Now to figure out why it won't run on my hardware 11/23. Is there a stand-alone debugger for bare metal stuff? I'd like to be able to single-step but ODT doesn't have that ability. Got spoiled by SIMH.
- Peter On Sat, Nov 1, 2025 at 7:23 AM Jay Logue via cctalk <[email protected]> wrote: > Classic stray LTC interrupt. You can disable LTC interrupts in simh by > setting the NOBEVENT option (11/23 and 11/03 only). This simulates > disabling the LTC via the front panel switch or a jumper on the CPU > board. E.g.: > > $ pdp11 > PDP-11 simulator V4.0-0 Current git commit id: 5cfa8662 > sim> SET CPU 11/23 > sim> SET CPU 32K > sim> SET NOBEVENT > sim> RESET > sim> load loop.bin > sim> g 14000 > ^E > > Simulation stopped, PC: 014006 (BR 14004) > > Note that a RESET is need after NOBEVENT is set in order for it to take > effect. This is because the NOBEVENT option effectively changes the > default value of the Interrupt Enable bit in the LTC control register > upon a system reset. > > --Jay > > On 10/30/25 07:39, Peter Ekstrom via cctalk wrote: > > Anyone here familiar with programming the 11/23 (KDF11-A) in assembler, > > bare metal? > > I have been trying to get a very simple test program to run on it but it > > keeps halting on > > an address outside of the program. Seems to always be the same address > > which is why > > I am thinking I must be missing something. The program runs fine on an > > 11/23+ or 11/70. > > [...] >
