Platform3 (testing prototype)

Rayman · 2026-01-26 22:59

Actually there's Schottky diode right there so tried powering after that, ~4.8 V.
That worked color wise, but battery bank still turned out.
Going to see if two WS2816B is enough...

Rayman · 2026-01-27 14:41

Found that two WS2816B LEDs in white draws enough current to keep the battery pack on.

Tried reducing the on time to conserve power.. 50% duty like below works, but less than that doesn't seem to work...

PUB Main | pos

  strip.start_b(LEDS, STRIP_LEN)                                ' start led driver
  strip.off

  repeat
    strip.set_all(strip#white)
    pause(5000)
    strip.set_all(strip#BROWN)
    pause(5000)

macca · 2026-01-27 15:33

@Rayman said:
Was hoping that cheap USB keyboards would support PS/2 mode, but the two tested just now didn't work.

[...]

Anyway, going to go forward with dual USB wired for PS/2 instead of real PS/2 just because is smaller and looks better.

Just in case you missed it, there is a USB driver for the P1 https://github.com/SaucySoliton/propeller-usb-host

Rayman · 2026-01-27 15:59

Thanks @macca that looks better than last time I looked at it. Still, main problem there is that I/O pins have to be in 0..7 range.
Doesn't work in this particular instance...

JonnyMac · 2026-01-27 16:33

In a very large number of my P1 projects a launch an internal support cog that runs a 1ms loop and calls very tasks that have their own timing variables. It turns out that you can get quite a lot of work done in a millisecond in the P1. This might be something to consider for your controller -- you're trading one cog (WS28xx) for this; that said, you can control a standard LED and a whole lot more, and use the LED as a 1s "heartbeat" indicator.

This is the background code in the demo.

con { background cog }

var

  long  bcog                                                    ' background cog #
  long  bcstack[32]                                             ' stack for background cog

  long  millis                                                  ' global milliseconds register


pri background | t                                              ' launch with cognew()

  io.low(LED_26)

  millis := 0

  t := cnt                                                      ' sync loop timer
  repeat
    waitcnt(t += MS_001)                                        ' run loop every millisecond
    ++millis                                                    ' increment millis
    show_heartbeat


var

  long  hbms


pri show_heartbeat

  if (++hbms == 1000)
    hbms := 0

  if (hbms < 250)
    outa[LED_26] := 1                                           ' 100%
'   outa[LED_26] := hbms                                        '  50%
'   outa[LED_26] := hbms >> 1                                   '  25%
  else
    outa[LED_26] := 0

Rayman · 2026-01-27 17:51

@JonnyMac Something to keep in mind...

@macca Will see if can add pads for pulldowns so could then use for real USB using jumpers at least...

Rayman · 2026-01-29 01:25

Here's layout for VGA-PS2(on USB)-stereo-mic board, adapted from P2 version. Same size, but this one has a lot more resistors and caps...

Platform3 (testing prototype)

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