Technical discussions about Freescale (Motorola) DSPs (including the DSP56000, DSP56300, DSP56600, 56800 DSPs).
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Changing the BOOTMAP bit on 56F805 or family member - dsp_sense - Oct 26 15:59:00 2004
Does anyone have any experience with changing the bootmap bit in
SYS_CNTRL on the fly? I am trying to change it to 1 to access an
external peripheral in program space, but the processor appears to
reset/crash when I do this. I'd like to be able to change it to 1,
read the peripheral and then change it back to zero so I can still
access the bootflash.
Thanks for the help.
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Re: Changing the BOOTMAP bit on 56F805 or family member - Author Unknown - Oct 26 17:29:00 2004
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Try this:
#define BOOTMAP_A 0xFFEF #define BOOTMAP_B 0x0010 #define SYS_BASE 0x0000 #define SYS_CNTL (volatile unsigned short*)(SYS_BASE+0x0)
To set bootmap B use:
*SYS_CNTL = *SYS_CNTL | BOOTMAP_B;
To re-set to bootmap A use:
*SYS_CNTL = *SYS_CNTL & BOOTMAP_A;
Hope this helps
J.K. Herrera
-------------- Original message --------------
Does anyone have any
experience with changing the bootmap bit in SYS_CNTRL on the fly? I am trying to change
it to 1 to access an external peripheral in program space, but the processor appears to
reset/crash when I do this. I'd like to be able to change it to 1, read the
peripheral and then change it back to zero so I can still access the bootflash.
Thanks for the help.
_____________________________________ /groups.php3
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Re: Changing the BOOTMAP bit on 56F805 or family member - S L - Oct 26 18:07:00 2004
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This is basically what I was trying, except that I was using a bit set/bit clear. I tried
it your way and still have the same problem... the processor resets/crashes.
Also, I noticed you showed SYS_BASE defined as 0x0, I believe it should be 0xc00 or am I
missing something?
Thanks.
j...@comcast.net wrote:
Try this:
#define BOOTMAP_A 0xFFEF #define BOOTMAP_B 0x0010 #define SYS_BASE 0x0000 #define SYS_CNTL (volatile unsigned short*)(SYS_BASE+0x0)
To set bootmap B use:
*SYS_CNTL = *SYS_CNTL | BOOTMAP_B;
To re-set to bootmap A use:
*SYS_CNTL = *SYS_CNTL & BOOTMAP_A;
Hope this helps
J.K. Herrera
-------------- Original message --------------
Does anyone have any
experience with changing the bootmap bit in SYS_CNTRL on the fly? I am trying to change
it to 1 to access an external peripheral in program space, but the processor appears to
reset/crash when I do this. I'd like to be able to change it to 1, read the
peripheral and then change it back to zero so I can still access the bootflash.
Thanks for the help.
_____________________________________ /groups.php3
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