rs485 question - broadcast data

[macer_0001]

Hi,

I need to know if it is possible to broadcast the data of master microcontroller to all microcontrollers connected on bus using rs485? Or it is limited to one address at a time?

Thank you

 

[planet69]

you could program the master to transmit a 'general' command and all other slaves conditioned to accept the transmission.
Totally depended on how you write up your firmware.

 

[macer_0001]

Thank for your response. may i ask some sample code? I am using assembly language in programming 8051.

 

[Ivan Lim]

you may using SPI protocol or I2C protocol

 

[planet69]

if data were to be distributed over a distance, i don't think SPI or I2C would be suitable

 

[BurnOut_tesla]

If your other microcontrollers are far away from master, then RS485 is good choice.
About your basic question RS485 is meant for multipoint communication,
When you transmit data on RS485 bus, every controller listen, i.e. every controller receives the data. Now its upto ur algorithm and device adressing, which will decide if u want to process data or not.
For sample programm, you just write in slave controller common address like 0x00,
means if incoming data is for 0x00 device it will receive and process the data, it is called broadcasting.