6 Dec
2021
6 Dec
'21
7:36 a.m.
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 ??bercool? 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