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AM3703 NAND compatibility

Simon Dunn
Prodigy 30 points
Other Parts Discussed in Thread: AM3703

We have a customer who is designing a custom board based on a AM37x-evm module (AM3703 MPu) and they wish to replace the NAND flash with a MT29F2G16ABBEAH4-IT-E chip from Micron.

After reading the wiki article Determining compatibility between ROM Bootloader (RBL) and Raw NAND devices at http://processors.wiki.ti.com/index.php/Determining_compatibility_between_ROM_Bootloader_(RBL)_and_Raw_NAND_devices I have concerns that this chip isn't going to be a simple replacement for the EVM nand and I wonder if someone could verify my thoughts.

Based on the reference manuals for the AM3703 (AM/DM37x Multimedia Device
Silicon Revision 1.x - sprugn4r.pdf) and the NAND device (2Gb: x8, x16 NAND Flash Memory
Features - m69a_2gb_ecc_nand.pdf) I think the flash is compatible from a configuration / page size / block size / ECC point of view but I do not think it will work from a hardware recognition perspective.

From section 26.4.7.4 of the AM3703 TRM the ROM Boot Loader (RBL) will identify the NAND chip by issuing the READID command, verify the DEVICEID (from BYTE 1) is supported and then update the page and block sizes from BYTE 4.

Reading the NAND flash data sheet, the READID command is supported, the DEVICEID is compatible with the RBL tables but the RBL expects BYTE 4 to specify block and page sizes whereas on the Micron NAND chip BYTE4 specifies ECC level, Planes per CS, Plane size etc, page and block sizes being defined in BYTE 3.  After failing to detect the NAND correctly through the DEVICEID command it will then attempt to read ID2 which the MT29F2G16ABBEAH4 chip does not support.

From my understanding therefore, this chip is incompatible as:

  • AM3703 does not support the ONFI nand flash protocol
  • BYTE 4 of the nand chip does not conform to the format expected by the RBL
  • the nand chip does not support ID2.
  • AM3703 RBL does not attempt to retrieve NAND parameters via SPI.

Could someone confirm my suspicions or have I missed something glaringly obvious and this NAND device is actually compatible?  Also if my suspicions are correct and this chip is not suitable is there any documentation or recommendations of approved NAND devices for the AM3703?  I have looked but failed to find any.

TIA