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Message
From: Michael Unnebäck<michael@h...>
Date: Wed Jun 23 23:55:35 CEST 2004
Subject: [openrisc] start of execution
Hi all,I have a system with RAM at location 0x00000000 and FLASH memory at
0xF0000000.
In FLASH I have my boot code at adress 0xF0000100. I want OR1200 to
start execute
at that adress.
To do so I use the following define in or1200_defines.v
// Default Exception Prefix
//
// 1'b0 - OR1200_EXCEPT_EPH0_P (0x0000_0000)
// 1'b1 - OR1200_EXCEPT_EPH1_P (0xF000_0000)
//
`define OR1200_SR_EPH_DEF 1'b1
What happens is the following:
the first instruction is fetched from 0x100 (reading an undefined value
from RAM)
the second instruction is fetched from 0xF0000100
System does not boot.
If I place l.nop (0x18000000) at adress 0x100 with JTAG debug interface
system boots OK
when I press reset. But the startup gets a bit complicated ...
Any suggestion on how to solve the problem ?
/Michael Unneback
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