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Yes you can. You can send the data to all the receivers, which can all be assigned different IDs or addresses. The transmitter first sends the ID/address and then the data. So, the receiver can check if the data has been sent for it or not. You can also use a third pin for something like chip select. But this would require an additional pin for each receiver.
There's no problem with the 2 PICs running off different clock frequencies. Just make sure they use the same UART configuration.
The Clock rates of the individual MCU do not matter*.
You just have to select the same Baud Rate.
The CCS C compiler has easy settings where you can just use the "printf" command to send data over the RS232.
Just make sure that your settings in both the transmitter and the receiver are the same.
*Actually the clock rate of the MCU does impact since it causes a small error in the baud rate during transmit/receive. This is mentioned in the Data Sheet of the MCU. But this error is quite small and can be ignored.
Just search the CCS forums for sample programs using RS232. While CCS C is a simple compiler, it takes up a lot of memory, so be careful about that.
You have to use 1 extra pin for Chip Select. i.e., for selecting the slave. Do you want to send the same data from master to all the 3 slaves?
You also have to pull MCLR pin high by connecting it to Vcc/Vdd through a 10K resistor.
Yes I want to send the same information to all pics I will arrange the selection by software, by the way if I would use extra selection pin, should I connect the pins directly or should I add a resistor to between pins?
No need for resistor. You can connect it directly if both master and slaves operate at the same voltage levels i.e., 5v or 3.3v
If you are sending the same data to all the slaves then you don't need a chip select pin.
But this configuration is not working, I am using same software (just changing clock ) for pic to pic communication, but not valid for pic to 3-pics communication, any comment that made me crazy
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Dear internetuser2k12 , for my configuration should I remove the resistors, the thing I am afraid about is the resistors have a little capacitance-behaviour at high frequency may they are blocking the communication ??