[ECOS] AT91SAM7SE with external SDRAM

Chris Zimman czimman@bloomberg.com
Mon Aug 20 12:29:00 GMT 2007

> As soon as SDRAM config has been done at the right place is it enough
> change address/size values in mt_arm_at91sam7se512_rom.h/.ldi files so
> that ECOS uses SDRAM ?
> Why not to configure SDRAM in hal_hardware_init that seems to be the
first > C code section called from vectors.S, we don't have any skills
in ARM
> assembly here...

Most of the platforms use a templated setup in hal_platform_setup.h, eg.



        .long   0x01002529  // 0x01000000, 16MB,  2 cycles  after
transfer, 				    // 16-bit, 6 wait states
        .long   0x02002121  // 0x02000000, 16MB,  0 cycles after
transfer, 				    // 16-bit, 1 wait state
        .long   0x20000000  // unused
        .long   0x30000000  // unused
        .long   0x05002021  // 0x05000000, 1MB,   0 cycles after
transfer, 				    // 16-bit, 1 wait state
(MEC01 on CS4)
        .long   0x05102021  // 0x05100000, 1MB,   0 cycles after
transfer, 				    // 16-bit, 1 wait state
(MEC01 on CS5)
        .long   0x60000000  // unused
        .long   0x70000000  // unused
        .long   0x00000001  // REMAP command
        .long   0x00000000  // Standard read protocol
        .long   AT91_EBI    // External Bus Interface address
        .long   10f         // address where to jump


Figure out what the correct values for the EBI chip selects are for your
platform and then add them here.

Extensive ARM assembly skills are not required, just a little bit of
reading and perhaps stepping through the setup code with a debugger if
things don't go how you're expecting.


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