Problem in interfacing Xbee with at89s51 microcontroller

[harisharanyp]

Our project has simple task of sending some text from the laptop(one end) to the microcontroller(other end). Laptop and microcontroller are to be connected using wwireless connection. We have :two series2 XBees; two Xbee breakout boards (one with USB and another with DB9 port); microcontroller. We want to interface one Xbee with an at89s51 microcontroller. can anyone please guide us in interfacing these two? do we need to use a level-shifter at the tx-rx pins of xbee?
kindly help.

 

[Fadi Mkhayel]

yes of course bro, the levels given by the serial xbee pins are ttl with -7 and 7 volts. so what you need to do is to make these levels 0 and 5 volts inorder for the microcontroller to understand that these are uart data.

 

[harisharanyp]

yes of course bro, the levels given by the serial xbee pins are ttl with -7 and 7 volts. so what you need to do is to make these levels 0 and 5 volts inorder for the microcontroller to understand that these are uart data.

Can you suggest which type of level shifter to use ?

 

[Fadi Mkhayel]

i suggest that you should use a comparator of reference 0 and threshold 5v so if signal is -7 it will give 0v and if signal is 7v it will give 5v.
regards.

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i suggest that you should use a comparator of reference 0 and threshold 5v so if signal is -7 it will give 0v and if signal is 7v it will give 5v.
regards.