SDRAMC

[kmjackson]

Hi Mark,

Do have any code that initializes the SDRAMC and make use of it?  I want to use it for heap.


Thanks,
Kenneth

[mark]

Hi Kenneth

I have code for SDRAM initialisation on the AVR32 (but nothing for the SAM7). The code is based on ATMEL examples so if you look in the ATMEL framework you will be able to find similar initialisations:

Code: [Select]

    volatile int i;
    POWER_UP(PBB, (PBBMASK_SDRAMC));                                     // power up the SDRAM controller
    POWER_UP(HSB, (HSBMASK_EBI));                                        // and external bus interface
    // SDRAM interface
    //
    _CONFIG_PERIPHERAL_A(2, (EBI_DATA_0_A | EBI_DATA_1_A | EBI_DATA_2_A | EBI_DATA_3_A | EBI_DATA_4_A | EBI_DATA_5_A | EBI_ADD_0_A | EBI_ADD_2_A | EBI_ADD_3_A | EBI_ADD_4_A | EBI_ADD_5_A | EBI_ADD_6_A | EBI_ADD_7_A | EBI_ADD_8_A | EBI_ADD_9_A | EBI_ADD_10_A | EBI_ADD_11_A | EBI_ADD_13_A | EBI_ADD_14_A | EBI_ADD_16_A | EBI_ADD_17_A));
    _CONFIG_PERIPHERAL_A(3, (EBI_DATA_6_A | EBI_DATA_7_A | EBI_DATA_8_A | EBI_DATA_9_A | EBI_DATA_10_A | EBI_DATA_11_A | EBI_DATA_12_A | EBI_DATA_13_A | EBI_DATA_14_A | EBI_DATA_15_A | EBI_NWE_1_A | EBI_NCS_1_A));
    _CONFIG_PERIPHERAL_C(1, (EBI_SDA_C | EBI_SDWE_C | EBI_SDCK_C | EBI_SDCKE_C | EBI_CAS_C | EBI_RAS_C));

    // The SDRAM initialisation is a slim-line copy of the ATMEL reference code set up for this SDRAM type and speed
    //
    HSB_READBACK(SFR5, SDRAM_CHIP_SELECT);

    SDRAM_READBACK(CR, (0x421131d9));                                    // SDRAM configuration
    SDRAM_READBACK(MR, SDRAM_MODE_NOP);                                  // issue NOP in oder to start the generation of SDRAMC signals
    SDRAM_READ();                                                        // dummy read from SDRAM
    for (i = 0; i < 2000; i++) {}                                        // 200us delay
    SDRAM_READBACK(MR, SDRAM_MODE_ALL_BANKS_PRECHARGE);                  // issue a PRECHARGE ALL command to the SDRAM.
    SDRAM_READ();                                                        // dummy read from SDRAM
    for (i = 0; i < 5; i++) {}                                           // 15ns delay
    SDRAM_READBACK(MR, SDRAM_MODE_AUTO_REFRESH);                         // issue auto-refresh command twice for this device
    SDRAM_READ();                                                        // dummy read from SDRAM
    for (i = 0; i < 10; i++) {}                                          // 66ns delay
    SDRAM_READ();                                                        // dummy read from SDRAM
    for (i = 0; i < 10; i++) {}                                          // 66ns delay

    SDRAM_READBACK(MR, SDRAM_MODE_LOAD_REGISTER);                        // commit settings
    SDRAM_READ();                                                        // dummy read from SDRAM
    for (i = 0; i < 5; i++) {}                                           // 2 cycles delay
    SDRAM_READBACK(MR, SDRAM_MODE_NORMAL);                               // set normal mode
    SDRAM_READ();                                                        // dummy read from SDRAM
    SDRAM_READBACK(TR, 0x176);                                           // set timing register, after which the SDRAM can be used

Regards

Mark

[kmjackson]

Mark,

I'm actually using an AVR32.  It this code snippet already in the uTasker project; I can't find it.


Kenneth

[mark]

Kenneth

The code is from a uTasker 'based' project but it is not in the present AVR32 version (I had it in fnUserHWInit() in application.c). It is for an 32UC3A512 and works with the SDRAM oin the EVK1105 - other SDRAM types may need adjustments (?).

Regards

Mark