Recent Posts

1

Microcontrollers / Re: Memory model for Microcontrollers

« Last post by langwadt on Today at 07:56:45 am »

When you only have 2K of RAM you don't waste it with the usage of malloc

Dynamically allocating storage can allow you to store more things than you have space for had you used static allocation. You just can't store them all at the same time, but that may be perfectly OK in the application. For a small micro you would probably have a combination, with dynamic memory being allocated from a block of statically allocated memory.

Er... and malloc isn't the be-all and end-all of dynamic memory. Indeed, if you think that's how it has to be done then you could well be missing some really useful techniques.

 but for the things I do I yet have to run into an application that needs to share the available memory between different tasks.

then how do you manage to run any C at all without a stack?

2

EEVblog Specific / Re: EEVblog #978 - Keysight 1000X Hacking

« Last post by Anthocyanina on Today at 07:53:54 am »

I just received a used DSOX1102G today (eBay purchase) and unknowingly crapped all over it. I saw it was running FW 1.10, and there was a nice shiny new FW 1.20, just calling out my name.  I snapped a shot of the "About This Oscilloscope" page, prior to engaging my stupidity, which displayed a whole host of installed licenses, and displayed the BW as 200MHz. I just thought the seller had purchased licenses and upgrades (MSO, FPG, memMax, EMBD, AUTO, ALT, FLEX, PWR, SGM, MASK, TEL, BW50, BW20, BW10, BW7, FRC, AUDIO, DIS, EDK, WAVEGEN, AERO, VID, ADVMATH, FLEXC, DIS, DIS, VID, DVM, ASV, CABLE, SCPIPS, RML, SGMC, TOM, FWD), not knowing 200MHz wasn't even an offered BW for this scope. 

So, as I'm quite sure, everyone that has been on this ride for any time at all, already knows that my new shiny gem is now just a kinda dull penny. 70MHz with four or five items listed in licenses! Doh! Any guidance that might help me get back to whence my scope once was??

I guess I'm so used to snagging and loading the newest FW onto my Fractal Audio AF3, on the regular, that the other scenarios never even crossed my older brain.

Hell of an introduction, huh??
Cheers,
Lee

it's been a lot of pages since then, but maybe that scope has FERCSA's firmware installed? had? (it's not clear in your post what's wrong with the scope)

does the scope work fine? by the title of the thread you might already be aware that this scope does support 200MHz bandwidth but not through official means. those unofficial means include FERCSA's firmware, Bud's firmware, resistors setting the hardware configuration, and who knows if anyone else hacked their own firmware to unlock the options.

if the firmware you installed was from keysight's website, it could be that the previous firmware installed was FERCSA's. you could try installing Bud's 1.20 unlocked firmware and get all the working options back. if it was another custom firmware+hardware modifications, maybe ask the seller to send you the modified firmware and install it again?

3

Metrology / Datron 4808 with an indentity crisis

« Last post by binary01 on Today at 07:50:13 am »

Hi team.
I have an odd question that I am hoping some of you might be able to shed some light on.  I recently acquired a used Datron calibrator from the online gambling centre (beginning with e), which I believe is a 4808, but on closer inspection, it is showing limitations in accordance with the performance of a 4805.  For instance, it can only generate ACV up to 100 kHz, and the display resolution is 6.5d / 5.5d rather than 7.5d / 6.5d.  I have lifted the lid and checked the P/Ns of all boards and all boards are matching the 4808 parts rather than 4805, so I think the guts belong to 4808.
Does anyone have any clues?  My first guess was that one of the boards must have failed and was replaced with a 4805, but even the board that houses the EEPROM appears to be from a 4808...
Thanks, Liam

4

General Technical Chat / Re: What did you buy today? Post your latest purchase!

« Last post by tautech on Today at 07:42:33 am »

New local PC store.....one must support it right ?

2m HDMI cable
Logitech wireless mouse and KB set
64GB USB3 pen drive
5 port LAN switch.
300mm LAN cable
512GB SSD drive, USB3.2 and USB-C double ended thing.....I never knew they made them so small these days. 

5

Test Equipment / Re: POST Hacking Rigol MSO5000 - POST HACKING TUTORIAL - DEEP DIVE

« Last post by BTO on Today at 07:42:13 am »

Hi,
@BTO
I have some questions about using the MSO5000, which I ask you and other colleagues to repeat the test and help with the solution:

Dear @BTO, I can't bring the signals saved in (Ref1) and (Ref5) and (Ref10) to the screen. I can only run the most recent IMG brought from Drive (C), and if I press (CLEAR) the IMGs become inaccessible.
Check how to resolve this.   
Any colleague can comment on my question.
Translation with Google Translate.

Hi mate, the files are accessible,
Follow the instructions in the last post, I've also made a video that i will shortly post after i edit it.
In short
SAVE TO REF : Only saves the file to the screen
EXPORT : Save the file to the C Drive
IMPORT : Brings it back from the C Drive to the Screen

You can select any one of the 10 Reference Slots and Select any of the sources CH 1 - CH 4 + L.A. and In L.A. you can select any of the channels
from D0 - D15 for digital comparison

Anyway, it all works, i think you just didn't use the IMPORT option

6

Test Equipment / Re: New Rigol RSA5000 Real Time Spectrum Analyser

« Last post by flamin1q on Today at 07:41:43 am »

Your guide works perfectly! Thank you so much man! <3

7

Beginners / Re: Where to attach cable shielding for portable battery-powered device

« Last post by etaripeka on Today at 07:39:37 am »

Oh yea, I'm being dumb; there is no ground loop. Thank you!

8

Projects, Designs, and Technical Stuff / Re: Lars DIY GPSDO with Arduino and 1ns resolution TIC

« Last post by Solder_Junkie on Today at 07:39:28 am »

Check that you have connected the TIC (4046) correctly, I think one of the diagrams I saw had the pins wrongly marked.

See, including the "as built" pdf: https://www.qsl.net/g4aon/gpsdo/

SJ

[Every]

9

Beginners / Re: Beginner Oscilloscope that can be controlled via Python

« Last post by Doctorandus_P on Today at 07:35:14 am »

Any decent scope probably supports SCPI. Even my old Rigol 1052DS has it.
And of course, Every decent scope supports SCPI, if you make SCPI support part of the definition of a decent scope. 

Support is so common that they don't even bother to print it on the front panel for 10+ years.

But if you want to control your scope via SCPI, you can make extra good use of a 12 bit ADC in your scope. As long as you're viewing the LCD of the scope, 12-bit resolution is of limited use because it just does not fit on the display (but you can zoom, and use it for on screen measurements) (Except maybe with Rigol, which tend to do on screen measurements based on screen pixels instead of measurement data 

10

Beginners / Re: The old "Replace blue LEDs with red LEDs" 7 segment question (74HC595)

« Last post by kevin.gibbs on Today at 07:35:02 am »

You can turn down the brightness and not replace the resistors. However, you will reduce the adjustment range because the indicators cannot be turned on at full brightness. At night, it may be too bright (you can't reduce the brightness any further). So, I would change the resistors. Replacing seems like a lot of work, but it doesn't take much time to unsolder 50 resistors, clean all the pads, and solder the other resistors. You'll probably take longer to change the indicators than the resistors.