RK11-C indicator panel inlays?

Mike Katz bitwiz at 12bitsbest.com
Mon Dec 6 09:36:00 CST 2021

One dumb suggestion to make it easier to control 144 lamps is to use 
addressable LEDs.  You can control them in banks or all in a single 
serial line.  If you use a single line you can control all of them with 
just 1 GPIO.

Each LED requires 24 bits of data.  That would be 3,456 bits.  The 
WS2812B has a 300uS low start indication and 1.25 uS per bit.  That 
would mean it would take. 4.62mS to update the all of the LEDs.

Since these are tri-color LEDs you can control the color and simulate 
incandescent lamps (Simh and the PiDP-8/i do this with LED PWM via an 
x/y matrix).

Another advantage to the LEDs is once they are set, you don't have to 
talk to them again until you need to change something.

I am going to use a Raspberry Pi Pico RP2040 CPU's PIO co-processor to 
drive the LEDS from a 432 byte array in memory.  All I do is update 
which LEDs I want to change and the PIO DMAs the entire array to the LED 
chain once every 10mS (or slower depending on need).

On 12/6/2021 9:13 AM, Henk Gooijen via cctalk wrote:
> Van: David Bridgham via cctalk<mailto:cctalk at classiccmp.org>
> Verzonden: maandag 6 december 2021 15:52
> Aan: General Discussion: On-Topic and Off-Topic Posts<mailto:cctalk at classiccmp.org>
> Onderwerp: Re: RK11-C indicator panel inlays?
> On 12/5/21 4:43 PM, Henk Gooijen via cctalk wrote:
>> I am definitely interested. Never saw the RK-11C (except once on eBay some 15 years ago)!
>> However, I have *two* DX11 front panels with the 144 lamps & 4 ”paddle” connections boards.
>> I developed a 100x160 mm (Euro-card size) PCB with a PIC18F252 and 10 MCP23S17 ICs.
>> You serially send a command to the PIC and the PIC controls the MCP23S17 outputs.
>> Per command you control 8 lamps. On the PCB is one difficult part: a 4 position one-slot block
>> to put the 4 paddle boards in.
> Fun.  That's a way to get some more lights into your life.  I like it.
>> Given you have 144 lamps panel with the RK11-C front, what would you do to light up the lamps?
> I think the only reason to have an RK11-C inlay is if you have an
> RK11-C.  Otherwise I can't see that it makes much sense.
> The one other place I might, maybe, possibly see one being used is along
> with one of our QSICs or USICs.  I could add an option to drive an
> RK11-C inlay if someone really thought that was what they wanted but the
> RK11-F inlay that we came up with really is a better match and more
> functional (which is why we came up with it) as well as supporting the
> RP11 implementation that I'm sure I'll get working any day now (snort).
> Dave
> If this RK11-C “blinkenlight” panel would also become available in a 60% scaled format,
> I would buy it immediately. It would be an “übercool” addition to the PiDP-11/70 and
> my 60% scaled (“working”) RK05 drive. I only modified the files pdp11_cpu and pdp11_rk05,
> and added my own code to handle the 2 switches, 8 indicators and the door / disk loading.
> see https://www.pdp-11.nl/pidp1170/rk05/rk05startpage.html (at the bottom of the page).
> I will check whether it could be scaled to 60% using standard 3 mm (warm-white) LEDs
> (if those exist, else I would probably use yellow-ish).
> Henk, PA8PDP

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