Max3232

Using Arduino Programming Questions
#1

Hi, all Recently, I want to use arduino connect to pc with max3232. I hope the result will show on the Hyper Terminal. I tried so many times. It didn't work at all. I cannot read any data which I try to send to pc on Hyper Terminal. I only need send one number one time like 10.

Please help me.

#2

Please help us by posting your code and describing your connections and serial settings

#3

The MAX3232 is designed for 3.3V operation, not 5V operation. Yes, it "works" on 5V, but it doesn't give out the same voltage range as the MAX232. It could be that your serial port is sensitive to the voltage level and doesn't respond to the lower voltage the MAX3232 operates at.

#4

Thank you,majenko

Do you mean I maybe use MAX232 instead of MAX3232 for arduino? Or I can add a resistor on it.

#5

Much information is missing here. I believe the MAX3232 is only available in smt package. Is that what you are using? As the other guys mentioned, it's a 3.3V device, so how are you powering it?

Also, unless you have a very old PC with a regular serial port, you need a USB-to-RS232 adaptor, plus special drivers installed, to connect to the MAX. So, what are you using here?

#6

oric_dan: Also, unless you have a very old PC with a regular serial port, you need a USB-to-RS232 adaptor, plus special drivers installed, to connect to the MAX. So, what are you using here?

To give the OP the benefit of doubt (yes, dangerous...), he may have a serial card in his PC. This is common in laboratory situations where one needs to interface their new PC with legacy equipment. (It's also common for lab PCs to also include floppy drives, as some older test equipment (like our very reliable Textronix bench scopes) save data to floppies only.)

But, your other questions (that I snipped for brevity) are valid.

#7

you have a very old PC with a regular serial port, you need a USB-to-RS232 adaptor, plus special drivers installed, to connect to the MAX. So, what are you using here?

Thanks oric_dan I have a pc which is 9 years old. Is it old enough? Also I solder the pins on max3232 board, then plug into the breadboard. I tried 3.3v power it up. I still got nothing on my old pc. I am using mega 2560.

#8 
I have a pc which is 9 years old.

But does it have a hardware serial port and are you using it ?

#9

There are many possible problems here.

  1. a 9 year old PC is good, ;-), probably has a serial port.

  2. now, you need to check whether a MAX3232 can deal with 5V inputs, assuming your mega2560 is running at 5V.

  3. how is the 2560 wired up? On a breadboard? Isn't it a surface-mount part? How on earth did you wire all those pins? Are you sure it's powered properly, got crystals, all necessary pins wired?

  4. how did you program the mega 2560 in the first place?

  5. Assuming all of the other things are ok, does the comport show up in Hyperterminal when you plug in the board?

  6. another thing is, it's the most common thing in the world for people to have the Rx and Tx pins accidentally crossed when building DIY serial ports using MAX chips.

If I were jiggering something up, which I do all the time BTW, I'd use a 28-pin preprogrammed UNO chip in DIP28 package, eg http://www.adafruit.com/products/123

Ten times easier than a mega2560. Or I'd start with a UNO board, http://www.adafruit.com/products/50

#10