IDC Connection Timeout - How to Isolate the MAX232AEPE+

Hi All!

Okay so somehow I am managing to compromise the MAX232AEPE+ so it does not work correctly.
By not working correctly I mean I get an ICD Connection Timeout.

I have my main breadboard with the MAX232, DB-9 connector, and a 5V DC regulator.
Then I have a separate board (the sound project board) which also has its own 5V DC regulator.
The sound project board requires both 12V and 5V.
Both the breadboard and project board are operating from the same 12V source.

I am using the 16F628A PIC to turn on and off some NPN (2N3904) transistors which provide a ground to the sound module pins.
None of the pins for the PIC read more than 5V with no PIC installed so I know I am not back feeding 12V into the PIC.
The reason some pins will read 5V is there are some 10K pull up resistors.

So the basic question is how does one prevent injury to the MAX232AEPE+?

Thanks, Ed

You usually want to cut the power instead of ground...

Thnaks and maybe I did not explain things correctly? I have a module that produces submarine sounds such as a "Ping". This module runs on 12 volts. If you ground certain pins on the module you can select different sounds using 2N3904 transistors. My issue is with the interfacing the Tx and Rx pins on the PIC to the MAX232.

If you have 4 pins on the 16F628A that is not used already you can have them as outputs and then binary set these pins to represent 0-15 as sound number. The other pic just have to read 4 of it's inpins that are connected to the output from the 628A.

If you ground certain pins on the module you can select different sounds using 2N3904 transistors. . . . . .

The answer is yes, with the help from Marina at mikroe.

I posted the question here and mikroe.com just before the hack hit and got the answer during the "hack cleaning" so I thought it might help someone else to post the results.

Just bought the easyPIC v7 to experiment with after accidentally blowing up my melabs LAB-X4 and wanted to set up the mikroProg Suite to start "auto loaded" with the PIC and compiled file like the melabs Programmer.
Though it's not necessary in order to use the mikroProg Suite, it's nice to have it up and ready to go after compiling.

There's some question in my mind exactly what you are asking or trying to do (story problems are not my forte, sadly), but the MAX232 is a level shifting RS-232 interface chip and rated to take +/- 15 volts on the "PC" side, is it not? If you have the module "isolated" by 3904's and no more than 5V reaches the PIC, where is the issue?

The problem is spammers waking up old threads.

Robert

Quote:

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The answer is yes, with the help from Marina at mikroe.

I posted the question here and mikroe.com just before the hack hit and got the answer during the "hack cleaning" so I thought it might help someone else to post the results.

Just bought the easyPIC v7 to experiment with after accidentally blowing up my melabs LAB-X4 and wanted to set up the mikroProg Suite to start "auto loaded" with the PIC and compiled file like the melabs Programmer.
Though it's not necessary in order to use the mikroProg Suite, it's nice to have it up and ready to go after compiling.

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Haha, that's funny but not funny.
I thought I recognized my typing :wink:

This was part of an informational post I did some time ago.

Thanks Louie, he is gone . . .