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Thanks for the offer Gordon as I normally have a stupid question or two along the way. It should be simple enough to write the functions needed. The difficult part is for me to find the time.

My plan is to have an Android controlled function generator from 1hz to 25mhz when I am finished.

I found a AD9835 sparkfun breakout board among some other boards and thought it might be interesting to control from Espruino. No need to reinvent the wheel so I ask if anyone already has working code?

Those devices can also sync to another time source.

You are correct about the crystal but I wonder if the internal RTC is temperature compensated like the 3231.

I have experimented with many different hobbyist boards over the years and none of them were what I would call accurate time keepers unless they had an external RTC.

Should the Pico be as precise as DS3231?

If you are concerned about accuracy why not add a DS3231? Pico could check and update its own clock every minute if need be.

What about measuring the electrical resistance of the spring? It may require some amplification. Assuming it is metal.

I have done both with no improvement. Running XP in a VM allows me to access it for now. I may try creating a wireless system for it using a couple of wixels.

Was a cure for this found?

On my mac pro running 10.6.8 I can connect to Pico using putty without issue but the webIDE and another serial terminal running as chrome app can not.

The ones I am using are not the cheap ebay versions, but these from Sparkfun. They have on board regulators and filter caps. The biggest issue I had with them in the past was distance. I have never seen this kind of noise come from them.

Curious why the IRQ pin was not used?

I am not so sure the problem I am having is the nrf24. While I am seeing a lot of TX not received 30 I do not believe it is hardware noise. Now I suspect the javascript module code that drives it. Perhaps I will port one I wrote for a different micro just to see.

I did use the setReg function.

I have had sporadic success but my opinion of them is not very high either.

Today I have tried OLED displays, SD card, etc, and everything went fine. Once I started playing with nrf24 it was all down hill. I have a Sparkfun nordic fob that I use for testing and its not going well.

Is there a function or value in init that can set the channel? Something like nrf.setChannel(2); perhaps?

Are you saying that software PWM should not be possible?

I would do it on a pin per pin basis. If it supports hardware then use it to its limits. If the pin can only do software pwm then allow only a specific freq range. If parameters are outside the limits then throw an error.

IMO

I just need to put a for loop into it.

14 Mhz using assembly

Thank you for the quick and informative reply. I had tried everything I could think of last night and was never successful and now I know why. ;-)

I guess I only tested the "on" and not the "off". Your description is not making sense to my old brain. Any chance for a snippet code to turn off B4?

I tested those writes individually and they do turn pin B4 on and off.

I tried but I think its triggering so fast that it never comes fully on. Readings are very low and distorted. Probably need to add a delay.

var test = E.asm("void()",
                 "ldr  r2,gpiob_addr",
                 "movw  r3,#4",
                 "loopStart:",
                 "str  r3,[r2,#0]",
                 "str  r3,[r2,#4]",
                 "b  loopStart",
                 "bx  lr",
                 "nop",
                 "gpiob_addr:",
                 ".word  0x40020418"
                 );

You are correct. I was thinking for loop. Its been a looooong time since I did assembly.

Ok. Will test this when I get home from my day job. Maybe I will do some research and put it in a for loop.

Trying my hand at assembler but I am getting an error. Trying to toggle B3.

var test = E.asm("void()",
                 "ldr  r2,gpiob_addr",
                 "movw  r3,#4",
                 "loopStart:",
                 "str  r3,[r2,#0]",
                 "str  r3,[r2,#4]",
                 "bgt  loopStart",
                 "bx  lr",
                 "gpiob_addr:",
                 ".word  0x40020418"
                 );

Error is...
Assembler failed: Invalid number "gpiob_addr" must be between 0 and 1024 and a multiple of 4

@Gordon
Using your bind method the pico reports 22.28 Khz and the DSO reports 19.38khz.