hello everyone,
I have a RS485 based slave relay driver with 8 relays. The relays turn on at logic 0. Since the 89C51 has all ports as HIGH during reset, my relays should remain off. The problem that I am facing is that when I turn the power supply on, all the relays turn on momentarily and then back off. Is there a race condition during which the microcontroller is not gaining control of the relay command lines even though I have the 89C51 in reset since start? The reset is standard 10uF + 10k resistor to the ground, should I be focusing on changing those? I cant seem to find any other reason that would trigger the relays.
Can someone please explain what areas I am over looking...
Thanks in advance