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serial communication

serial communication does not works between two AT89c512 PI24 microcontroller without max232 weather there is possibilities for communication or we must use max232?

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  • MAX232 or similar is used when a microprocessor should interface with "the world". The RS-232 standard has a wider voltage range allowed and is short-circuit-protected etc.

    When two microcontrollers on the same PCB need to communicate, then there is no need for any MAX232 - assuming that the two processors have the same supply voltage and have the supply voltage turned on at the same time. If the voltage used is the same for both processors, then it's normally enough to have a series resistor of a couple of kohm between the two processors to protect from short-circuit in case one of the processors happens to reconfigure the I/O signal so you get two outputs connected to each other.

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  • MAX232 or similar is used when a microprocessor should interface with "the world". The RS-232 standard has a wider voltage range allowed and is short-circuit-protected etc.

    When two microcontrollers on the same PCB need to communicate, then there is no need for any MAX232 - assuming that the two processors have the same supply voltage and have the supply voltage turned on at the same time. If the voltage used is the same for both processors, then it's normally enough to have a series resistor of a couple of kohm between the two processors to protect from short-circuit in case one of the processors happens to reconfigure the I/O signal so you get two outputs connected to each other.

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