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tn2916_boot_from_nand_omap2420.fm - Rev. D 6/07 EN
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©2006 Micron Technology, Inc. All rights reserved.
TN-29-16: Boot-from-NAND with the TI OMAP2420 Processor
Stage 1: Processor ROM Code
If the device ID of the NAND Flash is not supported by the ROM, an attempt is made to
determine the configuration of the NAND Flash device by performing a READ ID2 oper-
ation. Contact your Micron representative for READ ID2 operation details. If both the
READ ID and READ ID2 operations fail, the ROM code performs a software reset on the
system.
Stage 1: Processor ROM Code
Stage 1 is the execution of the OMAP2420 processor ROM code. This ROM code cannot
be modified by the system designer. Only NAND Flash devices supported by the ROM
code can be used for boot-from-NAND with the OMAP2420 device. If the ROM code
does not support a particular NAND Flash device, contact a Texas Instruments represen-
tative to determine if additional ROM code is available that will support the Micron
NAND Flash device.
After a power-on-reset is initiated, the ROM code reads the SYS.BOOT register to deter-
mine the memory interface configuration and programs the general-purpose memory
controller (GPMC) accordingly. Then the ROM code issues a RESET (FFh) command (see
Figure 2) to the NAND Flash device, followed by a READ ID (90h) command (see Figure 3
on page 5). The READ ID operation enables the OMAP2420 processor to determine how
the NAND Flash device is configured and whether this device is supported by the ROM
code.
Table 3 shows the required SYS.BOOT register settings to support boot-from-NAND.
Micron NAND Flash devices are available in both x8 and x16 configurations; the Micron
NAND Flash device referenced in this technical note, MT29F1G08ABB, has a x8 inter-
face.
Table 2:
Micron NAND Flash Devices Supported by the OMAP2420 Processor
Micron Part Number
Density
Device ID
Bus Width
Page Size
(bytes)
MT29F1G08ABB
1Gb
A1h
x8
2,112
MT29F1G16ABB
1Gb
B1h
x16
2,112
MT29F2G08AAD
2Gb
AAh
x8
2,112
MT29F2G16AAD
2Gb
BAh
x16
2,112
Table 3:
SYS.BOOT Register
SYS.BOOT[3:0]
Device Type
3
2
1
0
1
1
0
0
x8 NAND Flash
1
1
0
1
x16 NAND Flash
