Max232

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GatorGnet

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Is there a major difference in the MAX232 models. I see a lot of different model numbers for the 16DIP ICs. We just need the cheapest to interface the 16F*** pics to RS232. I know some of them have multiple drivers but this is not needed.
 
GatorGnet said:
Is there a major difference in the MAX232 models. I see a lot of different model numbers for the 16DIP ICs. We just need the cheapest to interface the 16F*** pics to RS232. I know some of them have multiple drivers but this is not needed.
Click to expand...

hi Gater,
If its cost and only a single TXD/RXD line there are a number of single transistor circuits that work OK.

EDIT:
This is one option I use. [Ignore the text, its a clip from a full circuit]

 
Last edited:
Its just a 16F628a to the serial port. Could I just replace it with transistors? The MAX is only $1 but cheaper is always better.
 
maplins cheapest device is a max202. its what i generally use but it doesnt always work in my circuit. i could be doing somthing wrong though
 
3lectrokid said:
maplins cheapest device is a max202. its what i generally use but it doesnt always work in my circuit. i could be doing somthing wrong though
Click to expand...

hi 3,
The MAX202 should be OK, post a diagram showing how you are using it.?
 
here is the schematic i used:


i do not think it is the circuit itself but it is because im using non polarised capacitors. it could also be because i am building it on stripboard.

please can you tell me why it doesnt work. thanks
 

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hi 3,
The circuit diagram looks OK.

Measure the voltage on pins 2 and 6, let me know what it measures.

The voltage should be about +9v and -9v.
 
yeh. i'm getting +9v and -9v on the pins. i have just found that the pic can receive from the computer but the computer cannot receive from the pic. my code is fine because my pickit2 can communicate with the pic fully.

i have now tried the serial port on both my dos/win3.11 computer and my windows 2000 computer but it is the sane problem

thanks again eric. could it be a faulty chip
 
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