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8148 EVM NAND device

Eunhye Yang
Prodigy 160 points

Hello Everyone,

When I boot DM814xEVM (SW-1[11:0] 000000010010 SW-2[1:0] 10), i got the following log,

--------------------------------------------------------------------------

U-Boot 2010.06 (Aug 13 2012 - 18:17:06)

TI8148-GP rev 2.1

ARM clk: 600MHz
DDR clk: 400MHz

I2C:   ready
DRAM:  2 GiB
NAND:  HW ECC BCH8 Selected
NAND device: Manufacturer ID: 0x2c, Chip ID: 0xca (Micron NAND 256MiB 3,3V 16-bit)
NAND bus width 8 instead 16 bit
No NAND device found!!!

---------------------------------------------------------------------------

I could not access the nand device. (nand erase, write didn't work)

But after I changed switch setting to SW-1[11:0] 000010010010

nand device worked normally.

Could you explain why?

Is there other way to solve this problem?

  • 0
    Guru 31670 points

    Eun,

    I could find the following from the DM8148 datasheet. 

    DM8148 datasheet said:

    GPMC CS0 default Data Bus Width input. This pin is multiplexed between ARM Cortex-A8 boot mode and General-Purpose Memory Controller (GPMC) peripheral functions. At reset, BTMODE[12] is sampled to determine the GPMC CS0 bus width

    • 0 = 8-bit data bus
    • 1 = 16-bit data bus

    But I really doubt whether it is used in bootrom code. If it was used your first stage bootloader wouldn't have booted from NAND. 

    There is a code in u-boot for DM8148, where it checks for the BTMODE-12 pin and checks whether it is 0 or 1. Based on that it decides whether 16-bit or 8-bit NAND is connected and selects the bus-width. But whatever little I understood is that its just a logical convention that is followed, as I couldn't find any thing meaningful in the BTMODE-12 value which will decide NAND bus width, as BOOTROM doesn't care for this value.

    Hope my explanation is useful to you

  • 0 in reply to Renjith Thomas
    Prodigy 160 points

     Hi Renjith,

    I found following lines in "ezsdk_5_04_00_11_dm814x_Release_Notes".

    The release supports both 8 and 16 bit NAND flash. To use 8-bit NAND, set the CS0BW (buswidth)
    switch on the EVM to OFF state. To use 16-bit NAND, set the CS0BW (buswidth) switch on the
    EVM to ON state.

    Note: CS0BW switch is the 8th Pin on the EVM Boot Mode Switch.

    Thanks for your help.

    Regards,

    Eun