I have vector nav vn100 IMU that sends data serially rs232...I want to drive 4 servo motors using atmega32 upon roll angel from vector nav vn100..atmega32 can only drive 2 servos using hardware fast pwm mode 14...so I should to use two atmega32...so I should receive the vn100 message to the two atmega32...my question is ..does UART rs323 support one transmitter multiple receivers?
If you do not need the control lines, and the communication is only one way, then yes, you can connect the TX (transmit) of the IMU to the RX (receive) of both microcontrollers. On the other hand, connecting one RX to multiple TX is likely to burn something.
Note however that the ATmega MCUs do not support RS-232 communication. If you want to go this way, you will then have to attach an RS-232 transceiver to each MCU. If the distances are short (say, a few centimeters), I would recommend using “serial TTL” instead.