Good morning,

I have designed a small basic interceptor board sitting on the SAM data bus. However, I am unexpectedly running into issues (ie as soon as I insert the board - it acts as an interposer, not coil/flasher/insert get triggered properly). I'm using high impedance input buffers, plus when they are not powered they are "dormant". The design use two back to back 2x10 headers with direct connection between each signal.

I checked schematics thoroughly, and I really can't find any reason for the failure. So before I take out my scope to check on signal integrity, am I correct to assume that all Power/CPU board on Stern SAM up to Tron use the same logical design ?

I used Shrek/Indy manual which include power and CPU schematics, and as such I did not connect 9/10/11 (they are unconnected on the power board).

Oddly enough, pin 11 is connected on the CPU board, apparently identified as an A7 adress line based on the schematics, however it's left unconnected on the power board schematics. Could this cause problem specifically on Tron (that's my only SAM machine) ?

In retrospect, I should have wired all signals (ie 9/10/11) just to avoid uncertainty, I admit

Thanks