I'm confused with LA probes, please correct the un...
# mpw-2-siliconp
Praveen raj
04/01/2023, 7:38 PMI'm confused with LA probes, please correct the understanding I have if it is wrong.
Caravan template || firmware || Direction
la_data_in -> reg_laX_data_in -> (project to CPU)
la_data_out -> reg_laX_data -> (CPU to project)
reg_laX_oenb -> Output enable -> Turn to 1 if CPU want to write to LA
reg_laX_ienb -> Input enable -> Turn to 1 if CPU want to read to LA
t
Tim Edwards
04/02/2023, 2:06 AMThe "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.
👍 1
p
Praveen raj
04/02/2023, 1:12 PMThat make sense, Thanks!
Praveen raj
04/17/2023, 6:35 PM@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 20:24reg_la0_data = 0x01F00000; //[31:0]9 Views