Blinking Light program for PDP-11 - test-drb@ccmp.vtda.org

2 Dec 2004

The drawback of using the RESET instruction 000005 is noticed
when you have RX01 or RX02 drives connected to your system.
The INIT signal on the UNIBUS, asserted by the execution of
the RESET instruction causes all peripherals attached to reset.
For an RL01/RL02 drive you can probably see a lamp flash on the
front of those drives, but the RX floppy drives "clunk" with
their heads on INIT.
...
 From experience, running this little blinkenlight
program on an 11/35 is not fun for long, unless you are deaf because the
sound of engaging/disengaging the RX heads is *not* fun.
Sorry that you had to wait a little longer until Guy sent you
that program. I have it too, but could not find it ....

- Henk, PA8PDP.

...
  -----Original Message-----
 From: cctalk-bounces(a)classiccmp.org
 [mailto:cctalk-bounces@classiccmp.org]On Behalf Of Ashley Carder
 Sent: donderdag 2 december 2004 19:33
 To: General Discussion: On-Topic and Off-Topic Posts
 Subject: Re: Blinking Light program for PDP-11

 Tom Uban wrote:

 Ashley, 
 Did you get a response on your question? One point
 to keep in mind is that the various processor types
 behave slightly differently. The typical method used
 to do the "Cylon" lamp effect was to use the console
 switch/display register (777570). A pseudo code program
 would be something like this (translation left as an
 exercise for you:-):

          Write '1' to console display register.
 Lamp Loop:
          Load spin count into register 2.
 Spin Loop:
          Decrement register 2.
          Branch if non-zero to Spin Loop.

          Rotate the console display register value left.
          Branch to Lamp Loop.

 This code will continually rotate one lamp from right to
 left across the display. A more complex version would switch
 directions when the lamp hits either end.

 Now for the problem. Only some processors (45, 70, perhaps
 others, but I don't think the 35 or 40) support display of
 the console switch/display register.

 There may be some other more generic method that works on
 all processors, but I'm not sure what it might be...  

 Hi Tom,

 I got a little "single rotating bit" program, coutesy of Guy 
 Sotomayor,
 who's been a *BIG* help to me.  I used this little program to do some
 basic testing on my PDP-11/40.  It continually rotates one 
 lamp across 
 the display.  This program was loaded as follows:

 Load address 001000 
 Deposit 005000
 Deposit 005200
 Deposit 006100
 Deposit 000005
 Deposit 000775
 Load address 001000 and press Start.  
 You should see a bit rotate around on the data LEDs.

 If anyone has any more interesting programs that can be toggled in
 for "blinking light" effects, I'd be interested in trying them out.

 After toggling in a couple of these types of things with the front
 panel last night, I decided to move on to bigger things.  I hooked up
 an RL02 and was able to successfully boot RT11 v5.3, XXDP 2.5,
 and my Wofford Witch RSTS/E v7 system.  

 Life is good!!!

 Ashley