Please refer the image. For Example:When power failure occurred and power resumed means,some times outputs are switched ON with previous state without enabling the OE pin.How to avoid this issue.?
This surely doesn't happen. Outputs are tri-stated as long OE is disabled (High). Output registers have however undefined state before they are loaded from shift register.
Independent of register state: as long as OE is disabled the output is HIGH IMPEDANCE wich is neither defined as LOW nor HIGH ...
If you want defined LOW ro HIGH (when OE is disabled) you need to add pull-up or pull-down resistors.
Removed the IC from board and tired with shift register alone.During that time there is no output is switched ON.But when IC is used means,the outputs going to high at time required to MCU configure.When the 1st sequence is started after port configure of MCU,there is no error in shift register.
Sorry picked an wrong word.When MCU is removed the outputs of shift registers in low state.If MCU is connected with shift register means for the outputs are going to high state at initial time only.After running the port configure sequence outputs in shift register in low state