Recent Posts

1

Programming / Re: Angle wrapping in code, "easy" problem, need to double check

« Last post by ejeffrey on Today at 06:10:28 pm »

. any tips on angle-wrap-respecting code to determine if a supplied angle is inbetween (on the short side) another two supplied angles

If possible I would avoid this.  Specifically the "on the short side."  Instead, define this in terms of " counterclockwise from the first angle, before reaching the second." This gives a unique representation, allows you to define an arbitrary interval rather than restricting to things less than 180 degrees.  Then "x is within the interval [a, b)" becomes:

(x - a) mod 360 < (x - b) mod 360.

If you still need the behavior you asked for then handle that as an input transformation: if (( b - a) mod 360) > 180) then swap(a, b)

2

Security / Re: Microsoft repackages apps with a telemetry .NET wrapper

« Last post by bd139 on Today at 05:59:23 pm »

"Actually you can..."
There might be a simpler way, Windows locked away inside a VM, with some very strict firewalling of any potential telemetry which was trying to escape the VM performed by a trustworthy Linux host OS. That would be a solution for anyone needing to run a program on Windows which wasn;t Wine compatible (unfortunately not that great a fraction of Windows exe programs are Wine compatible, I'm lucky with the few legacy Windows programs I use).

That is literally what I'm doing. I have an EC2 instance in AWS running windows server. There is a SG configured so it can only service RDP. Software is pushed to it over remote folders.

3

Metrology / Re: ADR1399 reference

« Last post by Andreas on Today at 05:57:24 pm »

Hmm,

so you have around 1 ppm/K temperature drift.
I think that your DMM contributes most of the T.C.

Did you try to thermally isolate the ADR1399?
Did you do the TC-Compensation of the LM334 from datasheet or did you adjust the 2 resistors to minimum T.C.
(according to my experiences with LM334 for a LM399 project the resistor values from datasheet are not perfectly).

with best regards

Andreas

4

Beginners / Re: What function generator, that does a bit more than just a simple signal

« Last post by radiolistener on Today at 05:56:46 pm »

hmm... COM3, sounds like something from the ancient past. I think I had my 2400 baud modem on COM2 and mouse on COM1 in mid-90's.

USB serial interface is very popular these days, it also use COMx name on Windows.

Jokes aside, I'll try some time later. Of course I'm using Linux. Will see if it works with mono.

it should works with mono with no issue. Just add "mono" before command and provide proper name of serial port.

5

Microcontrollers / Re: Divide clock by 3 on a ATF16V8B

« Last post by Wiljan on Today at 05:55:06 pm »

No, it's impossible.
VHDL code use triggers with positive and negative clock edges. ATF16V8B have only positive clocked triggers.
You can create simple divider by 3 on it, but you've got not symmetrical output (with duty cycle 1//3 or 2/3 - on your choice)
And for ATF you need a special programmer (hardware), do you need any?

I don't know if this is possible on the ATF16V8B but this code will divide by 3 symmetrically only on the posedge of the clk

It's a cheat where you make a counter count to 3 and mux the output between 0, clk and 1 so I get the symmetrically from the clk input

Code: [Select]

module clk_div_3(
input wire clk,
output reg out);
 
reg [1:0] cnt = 0;
 
always@(posedge clk)
begin
begin
cnt <= cnt + 1;
    if (cnt == 2) cnt<= 0;
end
end


always@(clk)
begin
case(cnt)
2'b00 : out = 0;
2'b01 : out = clk;
2'b10 : out = 1;
endcase
end

endmodule

6

Beginners / Re: LC filtering for combined Vref/VDD of ADC

« Last post by T3sl4co1l on Today at 05:54:36 pm »

Bonus: LDO at least gives [the chance for a] more accurate supply/ref, potentially reducing calibration error.

My posts suggests the use of a shunt reference instead of an LDO which is a better option if power loss is not an issue. It doesn't suffer from reduced PSSR when operating close to Vin like the LDO.

Are you sure about that?

Tim

7

Projects, Designs, and Technical Stuff / Re: (Yet Another) DIY Multislope ADC

« Last post by iMo on Today at 05:53:21 pm »

..In my ADC version I use only 8 MHz, though I see it getting tight in some places to do the math. The same clock for the sync and RP2040 is definitely a good idea. If the PIO runs slower one would still want a phase adjust step and than could still use the PLL for the µC clock.
A direct USB link and thus need for the 48 MHz is not really there, as one usually wants an isolation layer to USB.

Why do you need that perfect sync at the clock level between 2040 and PIO? The 2040 and PIO have nothing common with the clocking, there is no clock domain crossing with missing sync. Those are fully independent, because they communicate via FIFO/interrupts (this handles the domain crossing), a kind of async communication.
The PIO is a bunch of cmos logic stuff, with perhaps 1ps or less jitter, which has no "direct signal lines" to the CPU, except the clock line.
The CPU and PIO share the clock in 2040, but there is no need on phasing or whatever. The design here is different to your AVR/ARM designs where your peripheries and core CPU were somehow phase depended, imho.

8

Projects, Designs, and Technical Stuff / Re: role of optocoupler for biasing drain of amplifiers

« Last post by john23 on Today at 05:49:00 pm »

Hello XVR, Could you please reccomend me a PMOS model i could use?

Also , I have attached the two plots from NDT3055L mosfet.How do you see that its problematics , from the Vds sweep i can have 20A.
How do you see thats its limited to only 4A?


Thanks.

9

Repair / Re: LED Strip lights flashing like a bad 90s rave

« Last post by fmashockie on Today at 05:43:32 pm »

I would be looking at IC1 or the BP3319MB LED controller.  Not yet for replacement, but for testing.  I have attached the datasheet for the BP3319MB.  It provides a bunch of information on how the controller works.  You can use this information to test the BP3319MB.  Is it in undervoltage or overvoltage lockout?  Is the PWM providing the correct frequency/waveform?  You can verify all this by probing the IC with a DMM and scope.

Now as someone else mentioned, the LED controller is on the primary side.  And with it being a PFC controller, there could be voltage as high as 400VDC across the large filter cap.  Therefore, it would be best if you used an active probe to check this IC with a scope.  A high voltage differential probe like the Micsig DP10007 is affordable and works great. 

I would also recommend (like someone else mentioned) testing the led strip without the driver. You can hook it up to a DC power supply. 

10

Computers / Re: Format a 256GB pendrive with FAT32 using a windows 10 pc

« Last post by langwadt on Today at 05:40:59 pm »

I seem to recall that you can format large FAT32 volumes in Windows using its bundled command line tools (format or something like that). The 32GB limitation is only imposed by the GUI.

afaiu you can do it on the commandline but it is very slow, so it's better to get a thirdparty tool