I am using PIC16F877A to do some serial transmission.
Diagram below is the connection between master PIC and slave PIC.
The master PIC will trigger RA pins to ask one of the slave PIC to send some data to ensure there is only one slave PIC will send the data to master PIC every single time.
All of the transmit pin of slave PIC is connected parallel with receive pin of master pin.
This circuit work perfectly when only 1 or 2 slave PIC connected parallel to master PIC, but it fail to transmit the data when 3 PIC connected parallel.
Any idea?
Diagram below is the connection between master PIC and slave PIC.
The master PIC will trigger RA pins to ask one of the slave PIC to send some data to ensure there is only one slave PIC will send the data to master PIC every single time.
All of the transmit pin of slave PIC is connected parallel with receive pin of master pin.
This circuit work perfectly when only 1 or 2 slave PIC connected parallel to master PIC, but it fail to transmit the data when 3 PIC connected parallel.
Any idea?