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Projects, Designs, and Technical Stuff / Re: Batteroo testing
« Last post by FrankBuss on Today at 05:28:25 pm »
It's a two minute video. Show the cutoff voltage, show the warning message, dismiss it, keep turning the voltage down.

You have to use real batteries. Batteroo will tell you that you can't use a power supply to simulate it and will explain it with some poor snails ;D
General Chat / Solar Voltage Drop.
« Last post by mmpaaker on Today at 05:27:39 pm »
i have a 100w solar panel and 100A Lead acid battery. with 20a solar controller. i was using it around year no any problem. now aim getting problem battery not charging.

i just remove all cables and check the voltage on solar its giving me 20.6 volt and very sunny time. once i connect the battery to the controller or direct to solar wire. voltage is drop 50%  it show 10.3v without any load.
 how to solve this problem?
You could have a look at "100V line" speaker and amplifiers (aka "installation" speakers). You can maybe re-use the transfo from such a speaker, of modify such an amplifier to suit your needs...
Beginners / Re: Some noob questions
« Last post by agehall on Today at 05:25:33 pm »
Why is it always necessary to explain via analogy?

It is not.

HOWEVER, going down the physics route to explain quickly becomes very complicated and if you understand that, you probably would not be asking the question in the first place. So the easiest way to get a good understanding of what is happening, it is usually easier to use an analogy to something most people already know.
Microcontrollers & FPGAs / Re: [C] Pointers - what is the point?
« Last post by JPortici on Today at 05:25:18 pm »
Meanwhile I'd like to suggest to Simon to buy a good book about programming C for microcontrollers. Judging by his other questions he is using mostly 8 bit controllers and on those pointers are better to be avoided anyway because they are slow. On a typical 8 bit microcontroller it is faster to use global variables (*). In general it is good to avoid pointers because they offer a myriad of ways to shoot yourself in your feet and problems are hard to debug. Range checking when accessing arrays is highly recommended.

IMHO the way array variables are automatically pointers in C isn't very consequent. After all a 'regular' variable could be seen as an array with only one element. This tends to confuse people because you see things like this:
Code: [Select]
int a;
int b[2];
memset(&a, 0, sizeof(a));
memset(b, 0, sizeof(b));

* On 16 and 32 bit platforms pointers are much faster because (usually) the memory layout and/or instruction set are better suited to use pointers.

agree with every single word.
Other that i sometimes use pointers to variable or structures in my PIC18 firmwares, i can spare some cycles and it's better to have to keep/update/debug one function instead of every copy of the same. Also fewer lines to read and check
Test Equipment / Re: New spectrum analyser versus second hand
« Last post by Mr. Scram on Today at 05:24:30 pm »
What kind of EMC pre-compliance are you looking for? You can forget about radiated emission for starters because you'll need antennas and an insanely expensive test chamber.

A test chamber should reduce background noise, but you should at least be able to tell whether you're in trouble with background noise included. I'm not sure about the antennas though.
Test Equipment / Re: How were old, analog oscilloscopes packaged?
« Last post by Berni on Today at 05:24:19 pm »
The stuff does not become rock hard. It becomes much like the soft kind of styrofoam. Its there mostly to spread a impact over a large area so that it does not get dented or cracks. It proabobly does not have enough give to significantly lower the G shock from dropping the box from a height, but should still be enough to save a CRT. If it was too soft then a big drop could cause a corner to push trough it and hit the floor directly, that would leave a good ding on the corner and send a more dangerous sharp G shock trough the instrument.

I have some test gear that arrived trough eBay with CRT screens and it was never a problem. Often the rest of the piece of gear is significantly heavier than the CRT itself. Like a 50kg spectrum analyzer with a tiny 5 inch CRT. So the mass of the stuff around it helps reduce the GS that the CRT is exposed to. The old gear is built like a tank.
More info friends, look what happens with a blocked chip (0x98) and a new chip (0xC8), send anything in the register 0x81, but at least tell us what are the fixed bytes and which change...
Please give your sketch.
I have 5 chips locked and 3 chips not locked.
I can check with your sketch sooner.
Microcontrollers & FPGAs / Re: Pulse generation using STM32
« Last post by newbrain on Today at 05:24:06 pm »
You mean Master/Slave? I mainly use CubeMX, I'll so appreciate if you explain by that. thank you

Yes, you need to use one general purpose timer as Master and one advanced-control timer as Slave.
IIRC from other threads you've started, you are using an STM32F4xx so TIM1 as advanced-control and TIM2 as general purpose should be available.

The need for an advanced control slave is due to repetition counter (TIM1_RCR) support:
Code: [Select]
If the repetition counter is used, the update event (UEV) is generated
after upcounting is repeated for the number of times programmed in the
repetition counter register plus one (TIMx_RCR+1).
that, together with with the one pulse mode (OPM bit in TIM1_CR1):
Code: [Select]
Bit 3 OPM: One pulse mode
0: Counter is not stopped at update event
1: Counter stops counting at the next update event (clearing the bit CEN)
and the use of a CCR will give us exactly what you need.
Figure 37 in the link I gave is very clear.

For CubeMX, see the attached pictures: ITR1 (trigger from TIM2) has to be selected as trigger source in TIM1, One Pulse Mode set, and update event as TRGO in TIM2.
The ADC must be triggered by the CCR1 of TIM1.

Up to you to set values/pre-scalers/interrupts etc. etc...

Of course other alternative configurations can be used, e.g. with TIM8 you don't need to set a CCR register and can directly use the update event to trigger the ADC...

The STM32 timers are a bit unfriendly, but definitely flexible and powerful.

Repair / Re: Repair / Toshiba C850-1G3 Satellite Motherboard / Short Circuit
« Last post by xan on Today at 05:22:25 pm »
Some news... bad or not ? ...After resolder a new IC FDMC8884 laptop turn on! but without pressing the power button.. just simply plugging the power cord...  :-//  what inspect from here ? maybe some bad soldering on IC cause this kind of issue ??
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