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@pjmelect: Thanks a lot! That are all excellent information. I think that I'll just go with "proposed design": with pull-up resistors regardless if the sd card won't be possible to remove.
Thank you all for your help.
Gabrijel
Well, sd card will be used just for write and once the data is written, it won't be erased or overwritten. So there is no problem that it will die because of write/erase cycle.
I've found circuits how to connect sd card, but looked to me that pull-up resistors are used to be sure that lines are...
Hi,
I am designing a PCB that will have micro sd card glued into sd card slot so there will be no chance of removing it (or disconnecting) from microcontroller. In such configuration, are pull-up resistors needed? As I understand, pull-ups are required on all pins except CLK and D3 pin?
Thanks...
Hi,
@KlausST: sorry, I was unable to find it so I asked... I apologize :|
@barry: by your opinion, switcher to 5V then two LDO would be a "compromise solution" (if I understand you well)...
Kind regards,
Gabrijel
Hi all,
I am designing a device that needs to have total 3 different voltage as Vdd:
1. chip: Vdd(min)=3.3, Vdd(max)=4.3, Vdd(norm)=3.8 with I(max)=2.6A
2. chip: Vdd(min)=3.14, Vdd(max)=3.46, Vdd(norm)=3.3 with I(max)=0.9A
3. chip (battery charger): Vdd(min)=3.75, Vdd(max)=6, Vdd(norm)=5 with...
Hi,
I don't have a scope but have a friend that has one. He is absent until end of next week, so I'll have to wait for him to be able to make some measurement. I was hoping that there is some way to solve the problem without a scope.... Will get back with the results (and possible a solution)...
Hi,
I am working on a device that uses M95 as GPRS modem. The problem I am experiencing is sudden strange behavior of my device. I have been developing it for 6 months now and it was working without any problems when connected to laboratory PS. As the device will be powered up by car 12V, I...
Hi Brian,
thanks for you explanation It was a real help and I also learned something new. I will put 100k for the base resistor (as transistor will be mostly on) just to save some small current.
Kind regards,
Gabrijel Erman
Hi Brian,
what exactly do you mean by this sentence: "If the source can sink current you can dispense with the 47K resistor." I can leave 47K out if the source can sink current? Hm, I think it won't be a good idea, while "STATUS" pin on GSM is marked as output and on the lower voltage level...
Hi,
thanks for all your opinions and possible solutions. As I understand all together, the best would be to use open collector and then in the microcontroller SW "invert" the logic: logical 0 would mean GSM on, and logical 1 would mean GSM off.
Schematic:
Will 4.7k be "small enough" to have...
Hi,
I am designing a circuit that has GPRS communication. The modem has an STATUS output but datasheet mentions only how to put a LED as in indicator (standard connection when LED is in collector side with an 300ohm resistor and emitter is connected to GND). I asked manufacturer if I can...
Hi,
I have a problem using external PS and programmer:( I use PicKit3 but, as the device I am developing needs more than 500mA current, I must use external power supply. Well, all that was working until yesterday when PicKit3 GND wire was completely melted out:oops: After testing everything on...
Hi,
I am designing a device that will have automatic switch to battery when primary power source is removed also charging battery when primary power is present. In my design, I will be using PIC24 and BQ24725A as battery charger controller. For the charger I will use proposed schematic from...
Hi,
Brian, thank you very very very much! You gave me exactly the information I needed. Thanks one again. I will give a try to the 1-wire and test the RS485. As all this is learning, I think this is the best I can do for myself and learn something;)
Kind regards,
Gabrijel
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