I m confused with LA probes please correct the understanding

Question

I m confused with LA probes please correct the understanding I have if it is wrong Caravan template || firmware || Direction la data in gt reg laX data in gt project to CPU la data out gt reg laX data gt CPU to project reg laX oenb gt Output enable gt Turn to 1 if CPU want to write to LA reg laX ienb gt Input enable gt Turn to 1 if CPU want to read to LA

Tim Edwards · Answer

The ienb bits allow the CPU to accept input back from the user project this includes enable bits for the wishbone signals passed back from the user project to the CPU This is meant to protect the CPU from improper connections to the user project The oenb bits do not control anything specific They are expected to be used by the user project to inform the user project when a control signal is being applied on the corresponding la data out bit The user project could then use that signal to multiplex an input between say the logic analyzer and an external pin But you could in theory use the oenb bits as additional outputs

Praveen raj · Answer

That make sense Thanks

Praveen raj · Answer

< Tim Edwards> Which means If I want to pass 1 8V from CPU to user project through the LA pin20 24 is the below description correct `reg la0 oenb = reg la0 iena = 0x00000000 31 0 ` `reg la1 oenb = reg la1 iena = 0x00000000 63 32 ` `reg la2 oenb = reg la2 iena = 0x00000000 95 64 ` `reg la3 oenb = reg la3 iena = 0x00000000 127 96 ` ` Turning on LA 20 24` `reg la0 data = 0x01F00000 31 0 `