I'm trying to run/power a MAX232 off an Arduino USB (5V and GND - onboard), but when I connect the Arduino the power light slowly fades.
Is this because of a bad connection or because the USB doesn't have enough power? I have a Mac btw.
Please see the attached photo.
The USB has more than enough power for the Arduino + a max232, so my first guess would be a short somewhere.
Show us a schematic how the MAX232 is wired to the Arduino.
Observe capacitor polarities.
Your pins 16 and 15 are not connected.
Hi, Karry,
Maybe i've got it wrong, but isn't pin 15 and 16 connected on the top right of the photo?
Thanks,
Cameron
Does anybody have any other suggestions?
Thanks,
Cameron.
Hi, Guys,
I've wired up my MAX232 (please see photo), and the power comes on from the Arduino board, and then slowly fades off.
Please note that I do not have the TX/RX lines connected because I just want to get it powered up for now.
I'm thinking that I either have it wired up incorrectly (pin 2 and 6 - are a little complicated for me - but i think i have it correct)
OR
My capacitors are very old, used, and maybe one is defective?
What do you guys think?
Draw a schematic of what you think you have - can't tell from the picture and the same colored wires.
What value are the caps? 1uF? Do you have the polarities correct?
See Figure 4.
I don't think there enough connections made - Vcc & Gnd don't seem to be connected even.
AND DON"T CROSSPOST - that just wastes our time.
16 is the top left in your picture.
1 indent 16
2 15
3 14
4 13
5 12
6 11
7 10
8 9
Hi, CrossRoads,
I'm sorry about the double post issue. I didn't see my original post, and re-posted (my fault - I didn't mean to waste your time. You guys always provide great help. sorry)
From your post I know what I did. I read the chip the wrong way. For example:
1 2 3 4 5 6 7 8
When in fact it is: (right?)
1 2 3 4 5 6 7 8
My question crossroads is do you think I damaged the chip by wiring it up the wrong way?
Cheers,
Cameron.
Can only say Maybe.
You applied +5 to pin 9, an output pin, that might be an issue.
You grounded pin 10, an input pin, that should be okay.
So, maybe.
Hi, CrossRoads,
I have changed the pins, which I think is correct but it still does the same thing. (please see attached - ignore the stuff to the bottom left)
Please can you check my connections now. What do you recommend? Should I plug in another chip and see if it works?
Thanks,
Cameron.
So, I think i mixed up by sending pin 2 to GND, and pin 6 to +. Once I switched them around the power stays on, but their is no data being transmitted.
I have enclosed a drawing I attempted to do. Sorry for all the questions. It's just super complicated all the connections.
I'm not sure if I've damaged the chip or I've made the wrong connections or what.
Thank you for all your help.
Cameron.
9 & 10 go with 7 & 8.
Hey, Crossroads,
I got it to work!!!!!!!!!!
I think the real thing that was confusing me/still confuses me is the charge pump. On PIN 2 and PIN 6.
So, I connected
Pin 2 > - Capacitor > + 5 volts
Pin 6 > + Capacitor > Ground
and it works. The datasheet for me is a bit confusing. Also when I put a multimeter on the capacitor on Pin 2 I get 5 volts, but when I put my multimeter on the Capacitor on Pin 6 I get 0.03 mvs. Strange huh?
I'm really surprised I didn't blow a capacitor or the chip doing all the strange things I did with it.
Thank you so much for your help with this. I really appreciate it.
Cameron.
Glad you got it working.
Couple more projects and you'll be comfortable with datasheets.
Ha! I thought it was working!
Something strange is happening! It works at 9600, but when I put the baud speed to 57600 all the characters come out strange. On the datasheet it says it supports speeds up to 120kbit/s
I'm thinking of a couple of issues:
I am just pluging the wires into the serial socket. Do you think that the connection is too loose? (I don't think this is the case because the same characters come through each time)
I messed the chip up when trying to get it to work before (seems odd that it works at a slower speed)
I don't have it connected right.
I'm lost :S
Thanks for anyones help.
Cameron.
Mmm I just changed it from a Software Serial to the normal Serial and it worked.
So, I guess the software serial is having a problem getting up to that speed.
But, on the online docs it says it supports way higher than 57600 kbps?
Can't help you there, never used software serial.
Hi, Crossroads,
Thank you anyway :). It's not a problem because i'm going to use the real serial ports from the chip. I think that maybe because I was using both the real Serial port, and a software serial port it just maybe wasn't handling it.
If I have time i'll test it and report it back. So other people can learn.
Cheers,
Cameron.
