no respond when Xbee connect with computer

[decarus]

i set up a circuit as the following using MAX232EP with 3.3V input

http://www.sparkfun.com/datasheets/Wire ... er-v12.pdf

the rs232 are from USB - RS232

when using X-CTU.. cannot detect.. what's the problem?
at terminal there it replies with a " . "
pls help

[decarus]

btw.. what is the default receiving address for Xbee pro?

[ober]

can you check the connection of your circuit? Make sure the voltage from regulator is 3.3V, connection to MAX232, capacitor value, check the MAX232 data sheet what is the minimum operating voltage, normal MAX232 require 5V to operate.

[decarus]

does it means i'll need two max232. 1 is 5 V powered that converts RS232 to TTL then the other max232 to lower the voltage to 3.3 with Vcc = 3V.

[ober]

does it means i'll need two max232. 1 is 5 V powered that converts RS232 to TTL then the other max232 to lower the voltage to 3.3 with Vcc = 3V.

No, you need to get clear with the operating voltage, not the logic interface voltage. If the MAX232 cannot operate, it mean it is useless. Thus, how can it convert voltage?

The function of MAX232 is to convert RS232 signal to TTL logic signal (0-5V), that is why sometime we call MAX232 as RS232 level shifter. But since the specification of normal MAX232 require 5V or >3.3V to operate, you need to find other type of RS232 level shifter.

You need to get a RS232 that operate with 3.3V, for example MAX3225, MAX3232CDR and more.

Finally, this might be one of the reasons the circuit does not work, do check all the voltage across your circuit to ensure the connectivity is correct.