Pax Writer
New Member
Hello experts
I suspect my question is quite trivial, but here goes:
I am currently designing a uCPU-board with the possibility to add other boards onto it as piggybacks later on. Its my plan to use a common 74hc138 to select each board, but I have only had experience in selecting/deselecting single chips at a time. So here's my question: How would you suggest that I design a selection circuit for each board? Is a simple transistor inserted serially in the ground-connection enough? Maybe a MOSFET? And in that case how (since I also have no practical experience with MOSFETs, only bipolars and FETs). Maybe you have a third approach.
Please go ahead and provide suggestions. Links and schematics for examples are most welcome, and I'll do my best to answer any questions.
Thanks
I suspect my question is quite trivial, but here goes:
I am currently designing a uCPU-board with the possibility to add other boards onto it as piggybacks later on. Its my plan to use a common 74hc138 to select each board, but I have only had experience in selecting/deselecting single chips at a time. So here's my question: How would you suggest that I design a selection circuit for each board? Is a simple transistor inserted serially in the ground-connection enough? Maybe a MOSFET? And in that case how (since I also have no practical experience with MOSFETs, only bipolars and FETs). Maybe you have a third approach.
Please go ahead and provide suggestions. Links and schematics for examples are most welcome, and I'll do my best to answer any questions.
Thanks