ELM
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Table 7-172. 16-bit NAND Sector Buffer Address Map
NAND Message bit addresses in the memory word
Memory
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Address
0 4215 4214 4213 4212 4211 4210 4209 4208 4223 4222 4221 4220 4219 4218 4217 4216
1 4175 4174 4173 4172 4171 4170 4169 4168 4183 4182 4181 4180 4179 4178 4177 4176
...
47 3463 3462 3461 3460 3459 3458 3457 3456 3471 3470 3469 3468 3467 3466 3465 3464
48 3447 3446 3445 3444 3443 3442 3441 3440 3455 3454 3453 3452 3451 3450 3449 3448
49 3431 3430 3429 3428 3427 3426 3425 3424 3439 3438 3437 3436 3435 3434 3433 3432
50 3415 3414 3413 3412 3411 3410 3409 3408 3423 3422 3421 3420 3419 3418 3417 3416
...
255 135 134 133 132 131 130 129 128 143 142 141 140 139 138 137 136
256 119 118 117 116 115 114 113 112 127 126 125 124 123 122 121 120
257 103 102 101 100 99 98 97 96 111 110 109 108 107 106 105 104
258 87 86 85 84 83 82 81 80 95 94 93 92 91 90 89 88
259 71 70 69 68 67 66 65 64 79 78 77 76 75 74 73 72
260 55 54 53 52 51 50 49 48 63 62 61 60 59 58 57 56
261 39 38 37 36 35 34 33 32 47 46 45 44 43 42 41 40
262 23 22 21 20 19 18 17 16 31 30 29 28 27 26 25 24
263 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8
The table can now be used to determine which bits in the buffer were incorrect and must be flipped. In this
example, the first bit to be flipped is bit 4 from the 49th byte read from memory. It is up to the processor to
correctly map this word to the copied buffer and to flip this bit. The same process must be repeated for all
detected errors.
7.4.4.3 Use Case: ELM Used in Page Mode
In this example, the ELM module is programmed for an 16-bit error-correction capability in page mode.
After reading a 528-byte NAND flash sector (512B data plus 16B spare area) with a 16-bit interface, four
non-zero polynomial syndromes are reported from the GPMC (Polynomial syndrome 0, 1, 2, and 3 are
used in the ELM):
• P0 = 0xE8B0 12ADDB5A318E05BE B0693DB28330B5CC A329AA05E0B718EF
• P1 = 0xBAD0 49A0D932C22E6669 0948DF08BE093336 79C6BA10E5F935EB
• P2 = 0x69D9 B86ABCD5EC3697FA A6498FEE54556EA0 1579EF7D60BA3189
• P3 = 0x0
Table 7-173. Use Case: Page Mode
Step Register/ Bit Field / Programming Model Value
Resets the module ELM_SYSCONFIG[1] SOFTRESET 0x1
Wait until reset is done. ELM_SYSSTATUS[0] RESETDONE 0x1
Configure the slave interface power management: ELM_SYSCONFIG[4:3] SIDLEMODE 0x2
Smart idle is used.
Defines the error-correction level used: 16 bits ELM_LOCATION_CONFIG[1:0] ECC_BCH_LEVEL 0x2
Defines the maximum buffer length: 528 bytes ELM_LOCATION_CONFIG[26:16] ECC_SIZE 0x420
Sets the ELM in page mode (4 blocks in a page) ELM_PAGE_CTRL[0] SECTOR_0 0x1
ELM_PAGE_CTRL[1] SECTOR_1 0x1
ELM_PAGE_CTRL[2] SECTOR_2 0x1
ELM_PAGE_CTRL[3] SECTOR_3 0x1
484
Memory Subsystem SPRUH73H–October 2011–Revised April 2013
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