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The connector that's a smidge misaligned is the one that carries GND and power iirc?

There's another problem in Snow Leopard, it's not only the appleUSBCDC driver, it's that Chrome is never calling the callback passed to chrome.serial.send() and that stalls everythhing in your chrome app. Chrome 49.xxx.112 is the culprit. Grrr.

Great! Now I have to learn the sequence of clock source swapping that works to change that, it seems I can't just poke the new multiplier value there, right?

Testing, yes, trying to find where the limits of this little cute chip are. Speaking of which... can I overclock it by setting the PLL multiplier to more than 9x?

Yesss, that's cut it almost in half, now it's only 139 ns. Are there still wait states for other reasons?

Thanks!

//STM32F103RCT6.pdf -> https://www.st.com/resource/en/reference_manual/cd00171190.pdf
//7.3.2 Clock configuration register (RCC_CFGR)
//Read RCC_CFGR (see section 7.3.2)
var a=peek32(0x40021004).toString(2);
while (a.length<32) a="0"+ a;
a
00000000000111010010110000001010

00000 000 0 0 0111 0 1 00 101 100 0000 10 10

RESERVED: 00000
MCO:        000 -> no clock (Microcontroller clock output)
RESERVED:     0
USBPRE:       0 -> PLL clock is divided by 1.5 (USB prescaler)
PLLMUL:    0111 -> clk*9 (PLL multiplication factor)
PLLXTPRE:     0 -> HSE clock not divided (HSE divider for PLL entry)
PLLSRC:       1 -> Clock from PREDIV1 selected as PLL input clock
ADCPRE:      00 -> PCLK2 divided by 2 (ADC prescaler)
PPRE2:      101 -> HCLK divided by 4 (APB high-speed prescaler(APB2))
PPRE1:      100 -> HCLK divided by 2 (APB Low-speed prescaler(APB1))
HPRE:      0000 -> SYSCLK not divided (AHB prescaler)
SWS:         10 -> PLL used as system clock
SW:          10 -> PLL selected as system clock
*/

//Put 000 into PPRE2
poke32(0x40021004,peek32(0x40021004)&~(7<<11));

Sweet :-)

Thanks!

With this:

var loop = E.asm("void()",`
    ldr    r2, port_A  //Load port_A in r2
    movw   r3, #57344  //Load mask in r3
loop:
    str    r3, [r2, #0]  //Set is r2
    str    r3, [r2, #4]  //Clear is r2+4
    b loop
    nop
    nop
port_A:
  .word    0x40010810
`);

LED1.write(0);
LED2.write(0);
LED3.write(0);

loop()

It takes 223 ns to loop once, but three cpu cycles @72MHz are 3*1e9*1/72e6= 41.6 ns, can I touch some clock setting somewhere to make it toggle faster?

Thanks,

The olimexinos have a second row in parallel with a sane .1" pitch all around so that you can use a perfo board. That's a good thing if you ask me. I would not solder the connectors, let the buyer choose whether to solder them or not, and where.

"The original Arduino design had a flaw and the connectors were not spaced at 0.1". This makes perfo board use impossible, so to keep the compatibility, we have the same spacing but we added next to this a connector on 0.1" which customers can use with perforated boards"

That's cool, I like it!

In other message I ask about reading a 57x57 pixels QRCode from the pixl's screen, the idea is that you read it with the phone and it takes you to a web page where you can configure it, so the UI of the device setup/config is just a matter of a bit of html+js that runs on the browser on the phone, and I'm relieved of having to program it all from scratch to run on the espruino.

Hey, could you please transfer these QRCode images to the Pixl and try to read them with your phone, please?

http://forum.espruino.com/comments/14464888/

Yes the idea is not to use the LDO, even remove it, unless I can find one with a few nA quiescent current and 100mV dropout voltage, in which case I could use 3 alkalines in series.

Gordon, with Pixl.setContrast did you manage to make it fully perfectly visible again, or only somewhat?

Thanks!

Yes the idea is not to use the LDO, unless I can find one with a few nA quiescent current and 100mV dropout voltage.

Gordon, with Pixl.setContrast did you manage to make it fully perfectly visible again, or only somewhat?

Thanks!

The wikipedia says it's got lots of error correction pixels :-P

Resampled to 57x57 pixels:
http://javascriptology.com/qrcode/qrcode_57x57.png
http://javascriptology.com/qrcode/qrcode_57x57.bmp

It works fine on the screen of my Mac, in a 128*64 rectangle that has 5.4cm diagonally:

Can someone try this please, please? :-)

Wow wow wow! :-P

Yep, the MIC5225 of the pixl has a better (~1/2) dropout figure than the MCP1703 in the MDBT42Q breakout, but that "Very low ground current 29µA", if that's that, is not so good.

The MDBT42Q .pdf says a couple µA in sleep mode, is that right?

It also says it can run from 1.7 .. 3.6V, I could run it straight from 2 big D alkalines in series (3 fully charged .. 2V discharged) and remove the LDO, but, will the LCD still be visible with just two volts? What do you think?

Thanks!

Hello!

I would like to check if a qr code like this:

https://upload.wikimedia.org/wikipedia/commons/3/38/Qr-code-ver-10.png

on the screen of the pixl can be read without a problem, but I don't have any pixl yet...

Can someone try this please?

66uA

That would be at three volts (from the coin cell)?
Or @5V (powered from USB -> LDO)?
Or at the output of the LDO (3.3V)?

Any idea why it's three times more? Perhaps the buttons' pullups or some other thing that's, sort of ~ easily, fixable?

Hey, not that it's bad, in any case!

I'll push it to this repo @ github^W gitlab soon-ish:

https://gitlab.com/xk/appleusbcdcdriver-10.6.8

Wow, that was fast, thanks!

If you are having problems with the USBCDC driver not working properly on Snow Leopard with the Pico since 1v92 (was working fine until 1v91), I have compiled a newer AppleUSBCDC that works fine.

I think I've seen already a reference to fw 2v00 somewhere in the docs :-)

Given their EOL plans for chrome apps for Windows, Linux and Mac OS, that would be a good thing indeed.

Thanks!

Hello,

The MDBT42Q page says "2.5 - 16V voltage input, 20uA power draw when advertising", as it's got an LDO (the breakout), is that 50µW @2.5V .. 320µW @16V ? Or, at what voltage did you measure 20µA?

In the pixl and the MDBT42Q, can the bluetooth stack and radio be turned off completely for good if not needed, to save power?

In the pixl, can the display be turned on and off when needed? And if so, would the power drop down to MDBT42Q levels (~50µW) with the display off?

Hey, thank you very much!

I think I'll better ask the other power related things in another post, to keep things tidy.

Good to know, thanks.

IIRC l've seen a benchmarks folder somewhere in the repository in github? Are there any benchmarks to see anywhere?

The lower the power the better for me, both in deep sleep and while running. Is that the mdbt42q?