On Saturday, April 11, 2015 at 10:45 PM, Alan Frisbie wrote: > I just booted an RSX system image on SIMH and discovered a > problem with missing hardware. My physical PDP-11 system has a > Codar Q-Timer calendar/clock board. There is a privileged task > which reads the date & time and sets it in RSX. An RT-11 > version also exists. > > What I would like to do is write a SIMH device which emulates > this board, but uses the host system date & time. It seems > pretty easy, but I want to know if anyone has already done something like > this.
Well, there are other simulators which have time of year clocks that do 'something like' this. The VAX780 TODR has behavior similar to this and it is implemented in vax780_stddev.c. The MicroVAX2 has a watch chip which has behavior similar to this and is implemented in vax_watch.c. Meanwhile, your device is a little strange since there doesn't seem to be a documented register interface to program it. The programming examples in the documentation at: http://www.bitsavers.org/pdf/codar/Q-Timer_Users_Manual_May84.pdf seem to call a routine in ROM provided on the board to actually interface with the hardware clock. - Mark _______________________________________________ Simh mailing list [email protected] http://mailman.trailing-edge.com/mailman/listinfo/simh
