I assume both boards operate on the same voltage? ----- Original Message ----- From: "Vasile Surducan" To: "Microcontroller discussion list - Public." Sent: Saturday, September 15, 2007 4:45 AM Subject: Re: [PIC] Problem With MAX232 > SM8223 appears it need +3V. So you need an RS232 transciever which run at > 3V. > http://www.npcamerica.com/pdf/SM8223.pdf > > On 9/14/07, mamad876 wrote: >> >> Hi all, >> >> Recently I made a Caller ID decoder using SM8223 chip and I decided to >> connect it's out put to computer serial port and I bought a MAX232 chip >> and >> I made a prototype board regarding to it's data sheet. >> My problem is when I use my decoder separately it works well (I think >> because actually I don't see the result but I can see the CID found >> signal >> with an LED connected to board) but just when I connect ANY PINS of my >> RS232 >> converter to the CID board (Even GND wire of my RS232 Pro board) it stops >> working (ie. LED doesn't show CID signal ). I tried to separate the Power >> supply of my boards but this time the same problem when connecting TxD >> (ie >> T1 pin) of MAX232 to CID decoder serial output was exists. >> >> NOTE: >> I tested my RS232 board with another board with PIC16f84 and it works >> fine! >> >> Does any one have a suggestion. >> >> Thanks in advance. >> MAMAD >> -- >> View this message in context: >> http://www.nabble.com/Problem-With-MAX232-tf4435736.html#a12654885 >> Sent from the PIC - [PIC] mailing list archive at Nabble.com. >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist