Forum Discussion
Yamada1
Occasional Contributor
1 year agoThank you for your reply.
I'm sorry to ask a second question, but I would appreciate it if you could explain the following points.
1) You said that the logic is initialized to '0', but does this mean that the final output will be '0' regardless of the configuration? If the logic Y=(A and B) or (C and D) is configured and this is initialized, does that mean that Y='0' will be the result if it is initialized regardless of the values of A to D?
2) You said that all I/O buffers are TRISTATE/HIGH-IMPEDANCE/HIGH-Z, but if the logic Y=(A and B) or (C and D) is initialized, what values will A to D have?
I apologize for the trouble, but thank you in advance.
FvM
Super Contributor
1 year agoHi,
when starting user mode, registers are initialized to 0 unless explicitly defined otherwise in your logic description.
Unregistered (combinational) signals are getting a logic level according to defined logic, this applies of course to unregistered outputs as well.
I don't understand your initial point 2. Inputs are getting the state driven to it externally. In case you are asking about non- tristated INOUT pins, they are reading back the state driving to it from the FPGA.
when starting user mode, registers are initialized to 0 unless explicitly defined otherwise in your logic description.
Unregistered (combinational) signals are getting a logic level according to defined logic, this applies of course to unregistered outputs as well.
I don't understand your initial point 2. Inputs are getting the state driven to it externally. In case you are asking about non- tristated INOUT pins, they are reading back the state driving to it from the FPGA.
- Yamada11 year ago
Occasional Contributor
Thank you for your answer.I apologize for not being clear enough.NurAiman_M_Intel told me that the I/O buffer during initialization will be TRISTATE/HIGH-IMPEDANCE/HIGH-Z regardless of the logic state.So, if the logic is Y=(A and B) or (C and D) and Y, A, B, C, and D are connected to INOUT pins, then I wanted to know what state A, B, C, and D will be at the time of initialization (0, 1, Hi-Z, the external state of the input pin is visible as is, etc.), which is the intention of question 2).I apologize for the trouble, but thank you in advance.