I'm in initial stages of designing a PCB to use a PCF8574 to control an L298 H-Bridge. If It will work OK I will be able to control about 50 motors( only need four) with just the I2C wires of the arduino.
Here is the question. The PCF8574 puts out about 10ma in source mode, which is what I will be using. Is 10ma enough juice to get the L298 to work? It works on the Arduino pins but they are approx. 40ma. What am I looking for on the datasheet of the L298. I think I am reading it wrong because it says enable current max is only 100 uA and 30uA typical, but I am turning it on with the arduino pin? Please clarify where I am not connecting the dots. Thanks.
I think I am reading it wrong because it says enable current max is only 100 uA and 30uA typical
This means it will never pull more than 100uA.
The Arduino can deliver 40mA maximum, but it does so only to devices that pull that much current.
Current is never pushed. It is always pulled.
OK thanks, I wasn't sure and didn't want to melt anything, or just the opposite, and not have enough power to turn on the transistor. Back to planning.