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Thanks... Sorry, I didn't pay attention... I under a lot of stress to finish this ASAP and I keep making a lot of mistakes!
I hope this one is correct!
I'd be thankful if you could remove the schematic in my previous post to preclude the possibility of someone using it!
Thank you very much...
Dear Klaus,
I think I wasn't able to describe how I want to use a single 74HC14 IC to drive two LEDs... one LED for RX and one LED for TX. I think using the word Pair made it vague.
This is the schematic. Is this correct? Any suggestions for improvement?
Thank you very much. :clap::thumbsup...
Dear Klaus and others,
As you know from my "MAX232/MAX3232 Heating Up" top, I am finalizing my circuit on a PCB. I am almost finished with this "RX/TX LED indicator with pulse stretching". Now I have one concern, so I thought I should check with you guys.
Datasheet says:
I am using two...
Thanks Klaus
Currently I am using MAX232CPE... I don't have MAX3232 around.
Which resistors are improvement? There are too many resistors on the circuit :laugh:
Of course I know how to calculate parallel resistors :laugh: The exact solution is: 4645.416357 and I don't know why I copy pasted...
Cost is not an issue for me! I only need to build one circuit that is doing the job correctly for a long time.
From what I see in official schematics....
Pin 10 and 11 are internally connected to 5V through a 400K resistor!
Pin 13 and 8 are internally connected to the ground through a 5K...
Thank you,
What is the purpose for putting the 100 ohm resistor in tx and rx lines? What are the pros and cons of using this resistor?
And also what is the purpose for putting the R2 resistor between 12 (TTL_RX) and 5V? What are the pros and cons of using this resistor?
Thank you,
Does it also apply if both sides of the cable (modem{sensor} and receiver{uC}) are using the same ground? Because I am supplying the 5V voltage from the same lead-acid battery (through a regulator)!
By the way, the sensor's wire is Cooner Wire with a Lemo Connector.
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What happens if the chassis of the cable is grounded at both sides?
I will change the capacitors and will notify you.
I have also removed the Vcc resistor, and tested the circuit with the 100k resistor connected between Vcc and 11 and 10 pins... it still heats up.
- - - Updated - - -
I...
Thank you very much everybody...
I searched the term "ferrite bead" in the google and I found out what it is!! I didn't know the name, and honestly didn't pay attention to it before. But I now for sure know that the original cable from the sensor doesn't have a ferrite bead!
Do you think that...
Dear Andre and other users.
In quest to save this problem completely, I see that a member on another forum, said this as a warning to the person who ran into the same problem:
When you design the circuit you didn't consider ESD considerations. I am sure that the shield of DB9 its connected...
ok...
To make sure ....
MAX232 Pin 11 is the pin that is currently connected to Arduino MEGA2560 pin number 18 which is TX1. So I should connect a 100k resistor from VCC to the trace that is connecting Arduino TX1 to Pin 11.
MAX232 Pin 10 is the pin that is currently unused... So instead of...
Thank you very much Klaus.
Is it possible to provide a schematic?!
I am still deeply grateful from your help with the LED indicator with pulse stretching!
Hi Klaus,
I haven't ordered the PCB yet. I mean, instead of designing a PCB without a resistor in VCC line, I am going to design a PCB with two traces... one with a resistor and one without a resistor... Quote from my last post "At least this way I am not required to order another PCB!"
In...
Thank you veI moved it 3 feet away and it still happens.
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No I only use one from RX and one from TX.
The more I read on the internet, the more I am convinced that the symptoms are related to latch up! How can I stop latchup from happening?!
I cannot disconnect the...
I haven't measured the Vcc during the overheating.
I think it is adequately sized...
I tried to power up the MAX232/MAX3232 with Arduino Mega2560 5V output which only powers up a RF transmitter and several n-channel MOSFET's gate.
I have also tried to power it up with a dedicated LM7805 with a...
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