Hi,
I am trying to design a 8layer board
When I design: I design an application. And the application requirement tells how much layers I need to use. And for what "signals" these layers are used for.
It seems you doing it the other way round. You design an 8 layer board. Try to find which signals you want to route in the according layers.. then you look for an application which fits this requirement. Interesting....
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I agree with Barry, there are no rules. But there are many discussions here in the forum and in the internet.
But most of them start with:
"I´m designing a HF board with ... requirements.."
"I´m designing a high densitiy FPGA board with ... interfaces... I/Os, devices..."
"I´m designing a high power inverter....."
"I´m designing a high precision multi channel data acquisition board.....with 16 bit precision and 10MHz bandwidth..."
Then it additionally depends whether / how much you want an autorouter to route the signals in the accrding layers.
Klaus