Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

Problem with asynchronous reset and booting

Hello I have the NIOS configured to boot the boot from the on-chip memory. The first time successful startup. When you reset the NIOS using asynchronous reset signal the BOOT not load a softwa...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
12 years ago

You will need both a ROM and a RAM. A ROM to hold the software, and a RAM to hold the exception vectors and all the variable sections (data and bss, mostly). Remember in the Nios CPU configuration to set the reset vector to your ROM and the exception address to your RAM.

There isn't any BIOS but yes you can configure your system to boot from an external rom. If it is a parallel ROM, then you just have to set the Nios's CPU reset vector to this ROM. If it is an EPCS, then set the CPU's reset vector to the EPCS controller address. The controller has a small ROM that contains a bootloader able to load a software image from the EPCS and recopy it to RAM.