Starting System Console

• From SOPC Builder, click Tools --> Launch System Console
  
• From Nios II 8.0 Command Shell, type "system-console"
  • If you have the Quartus Project handy, try "system-console -jdi=<quartus_proj>.jdi".  This will give System Console more information about the JTAG nodes in your system.

Reading and Writing Memory with a Nios II Processor

This assumes that only one Nios II Processor exists in the system.  If one or more Nios II's or a JTAG Avalon Master exists, then in Step 1 you might have to change the list index to get the correct master.

0.  <From System Console shell>
1.  set nios [ lindex [ get_service_paths master ] 0 ] - might need to change the index number if there are > 1 masters.
2.  open_service master $nios
3.  processor_stop $nios - the Nios must be in debug mode to access memory 
4.  master_read_memory $nios 0x00000 4 - Read 4 bytes starting at address 0x00000.
5.  master_write_memory $nios 0x00000 [ list 0xaa 0xbb 0xcc 0xdd ]  - Writes 0xaa to address 0x0, 0xbb to addr 0x1, etc.
6.  close_service master $nios - release SLD Node lock when finished.