So far I have somewhat successfully used a shift register (74HC595) and an output expander (PCF8574) to control FETs and BJTs. The main drawback so far seems to be that the chips I’m using have undefined values for the output pins at power on, so sometimes the pins are high, sometimes low (and it appears somewhat random). The upshot is that I before my microcontroller comes online and initialises the shift register or output expander, the system is in an undefined state (and things randomly turn on that aren’t supposed to).
I’m not asking for a product recommendation, but some guidance on how to effectively and correctly find a shift register or output expander which has guaranteed low signal on the output pins at power on would be very helpful. Is it a case of trawling datasheets, or is there a more effective way to find the chip I’m looking for?