PDP 11/45 light chaser

Jay, this is the one I used: Location Content Op-code comment 001000 012700 mov #1,r0 load ro with 1 001002 000001 001004 006100 rol rotate r1 left 001006 012701 mov delay r1 load register r1 with delay 001010 007777 delay 001012 005301 dec r1 decrement register 1 001014 001376 bne -2 continue to decrement r1 until r1=0 001016 000772 br -12 back to 001002 (dec r0) it's not elegant, but you do get to see the lamps light, you can change the speed by altering the "delay" value. It doesn't work to well, as the data display will show the load of r1 as well. Yo should be able to alter it to put the lght chaser into the console display register (you'll have to re-calculate the value of the final branch - it will need an extra two memory loactions, one for the mov display register instruction, and one for the location of the register). I haven't got this to work on my 11/45, as I get a memory address error when I try to write to the display register, though I'm told I should be able to write to it - I think there is a processor fault lurking in there somewhere, or possibly a fault in the memory management module, though this is less likely, as I can read and write to the DL11W serial port. Jim. Please see our website the " Vintage Communication Pages" at WWW.G1JBG.CO.UK