AT91SAM9261 boot code for embOS + NOR Flash?

mtconnol · Nov 14th 2007, 7:06pm

Hi Segger folks,

I'm trying to boot a custom board based on the Atmel AT91SAM9261. I have a 16-bit NOR flash on CS0 which appears to work (I can boot into a GPIO toggler application running directly out of Flash) but I'm not sure how to get booted into the embOS environment. I'm using the IAR development environment.

My attempts to boot from flash have yielded an unresponsive board. When I reattach to it with the J-Link, it appears to be stuck in a loop hitting the undefined instruction exception vector repeatedly.

Is there any sample code that shows booting from NOR flash, copying the application into internal SRAM, and remapping?

Thanks much.

Michael

Souhail · Nov 15th 2007, 5:45pm

Hi mtconnol,

To do this, you need to do several steps:

Modify the link file.
Since we want to copy the application into internal SRAM, we must reserve some RAM for this.
Therefore the DATA segments is after this area.
C Source Code
1. //*************************************************************************
2. // XLINK command file for AT91SAM9261 using an external NOR flash
3. //
4. // Usage: xlink -f lnkarm <your_object_file(s)>
5. // -s <program start label> <C/C++ runtime library>
6. //
7. //*************************************************************************
9. //*************************************************************************
10. -carm
12. //
13. // These settings are used for link the application.
14. //
15. -DROMSTART=00000000
16. -DROMEND=00028000
18. //
19. // Define the internal SRAM.
20. //
21. -DIRAM_START=00300000
22. -DIRAM_SIZE=28000
23. -DIRAM_END=(IRAM_START+IRAM_SIZE-1)
25. //
26. // Define the external SDRAM.
27. //
28. -DSDRAMSTART=20000000
29. -DSDRAM_SIZE=4000000
30. -DSDRAMEND=(SDRAMSTART+SDRAM_SIZE-1)
33. //
34. // These defines are used for copying the code from ROM to RAM.
35. // We reserve 1/2 of the SRAM for this. (80kByte)
36. //
37. -DRAMCODE_START=IRAM_START
38. -DRAMCODE_SIZE=14000
39. -DRAMCODE_END=(RAMCODE_START+RAMCODE_SIZE-1)
41. //
42. // Read/Write segments are after the reserved "RAMCode segement".
43. // You can alternatively use the external SDRAM for this.
44. // This will look like this:
45. // -DRAMSTART=SDRAMSTART
46. // -DRAMEND=SDRAMEND
47. //
48. -DRAMSTART=(RAMCODE_END+1)
49. -DRAMEND=IRAM_END
52. //*************************************************************************
53. // Address range for reset and exception
54. // vectors (INTVEC).
55. // The vector area is 32 bytes,
56. // an additional 32 bytes is allocated for the
57. // constant table used by ldr PC in cstartup.s79.
58. //*************************************************************************
59. -Z(CODE)PROGRAM_START=ROMSTART-ROMEND
60. -Z(CODE)INTVEC=ROMSTART-ROMEND
62. //*************************************************************************
63. // Startup code and exception routines (ICODE).
64. //*************************************************************************
65. -Z(CODE)ICODE,DIFUNCT=ROMSTART-ROMEND
66. -Z(CODE)SWITAB=ROMSTART-ROMEND
68. -Z(CODE)RAMCODE=RAMCODE_START-RAMCODE_END
70. //*************************************************************************
71. // Code segments may be placed anywhere.
72. //*************************************************************************
73. -Z(CODE)CODE=ROMSTART-ROMEND
75. //*************************************************************************
76. // Various constants and initializers.
77. //*************************************************************************
78. -Z(CONST)INITTAB,DATA_ID,DATA_C=ROMSTART-ROMEND
79. -Z(CONST)CHECKSUM=ROMSTART-ROMEND
80. -Z(CONST)PROGRAM_END
82. //*************************************************************************
83. // Data segments.
84. //*************************************************************************
85. -Z(DATA)DATA_I,DATA_Z,DATA_N=RAMSTART-RAMEND
87. //*************************************************************************
88. // __ramfunc code copied to and executed from RAM.
89. //*************************************************************************
90. -Z(DATA)CODE_I=RAMSTART-RAMEND
91. -Z(CONST)CODE_ID=ROMSTART-ROMEND
92. -QCODE_I=CODE_ID
94. //*************************************************************************
95. // ICCARM produces code for __ramfunc functions in
96. // CODE_I segments. The -Q XLINK command line
97. // option redirects XLINK to emit the code in the
98. // debug information associated with the CODE_I
99. // segment, where the code will execute.
100. //*************************************************************************
102. //*************************************************************************
103. // Stack and heap segments.
104. //*************************************************************************
105. -D_CSTACK_SIZE=(100*4)
106. -D_IRQ_STACK_SIZE=(8*8*4) // 8 nesting levels, 8 registers saved, 4 bytes each
108. // System and IRQ stack should reside in internal RAM if possible
109. -Z(DATA)CSTACK+_CSTACK_SIZE=RAMSTART-RAMEND
110. -Z(DATA)IRQ_STACK+_IRQ_STACK_SIZE=RAMSTART-RAMEND
112. //*************************************************************************
113. // ELF/DWARF support.
114. //
115. // Uncomment the line "-Felf" below to generate ELF/DWARF output.
116. // Available format specifiers are:
117. //
118. // "-yn": Suppress DWARF debug output
119. // "-yp": Multiple ELF program sections
120. // "-yas": Format suitable for debuggers from ARM Ltd (also sets -p flag)
121. //
122. // "-Felf" and the format specifiers can also be supplied directly as
123. // command line options, or selected from the Xlink Output tab in the
124. // IAR Embedded Workbench.
125. //*************************************************************************
127. // -Felf
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Copy your embOS application into internal SRAM.
We can do that in __low_level_init().
Add following lines to your __low_level_init() after PLL initialization:
C Source Code
1. {
2. #define MATRIX_MCFG (*(volatile unsigned long *)(0xFFFFEE00))
4. #pragma segment="RAMCODE"
5. #pragma segment="PROGRAM_START"
6. #pragma segment="PROGRAM_END"
7. void * pSrc = __sfb("RAMCODE");
8. void * pDest = __sfb("PROGRAM_START");
9. OS_U32 Size = (int)((OS_U8 *)__sfb("PROGRAM_START") - (OS_U8 *)__sfb("PROGRAM_END"));
11. //
12. // Copy ROM to internal SRAM
13. //
14. memcpy(pDest, pSrc, Size);
15. //
16. // Remap internal SRAM to 0
17. //
18. MATRIX_MCFG = 0x03;
19. }
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Let me know if this solves your problem.

Souhail

AT91SAM9261 boot code for embOS + NOR Flash?

AT91SAM9261 boot code for embOS + NOR Flash?

Atmel AT91SAM9261 NOR boot code

C Source Code

C Source Code

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