NAND08GAH0A NUMONYX [Numonyx B.V], NAND08GAH0A Datasheet - Page 110

• Manufacturer Part Number: NAND08GAH0A
• Manufacturer: NUMONYX [Numonyx B.V]

Error protection
11
11.1
Figure 50. CRC7 generator/checker
110/116
CRC 6… 0
Error protection
All commands, responses and data transfers are protected against transmission errors by
CRC (cyclic redundancy check) codes.
One CRC is generated for each command and checked for each response transferred
through the CMD line. For data blocks, one CRC per transferred block and per data line is
generated.
If the addressed device CRC check fails, the device does not respond, and the command is
not executed.
CRC7
The CRC7 check is used for all commands, all responses except responses of R3 type, and
for the CSD and CID registers. The CRC7 code is a 7-bit value.
It is computed as follows:
The generator polynomial is
All CRC registers are initialized to zero.
The first bit is the outmost left bit of the corresponding bit string of the command, response,
CID or CSD).
The degree n of the polynomial is the number of CRC protected bits decreased by one.
The number of bits to be protected is 40 for commands and responses (n = 39), and 120 for
the CSD and CID (n = 119).
M x ( )
[
=
firstbit
]
=
Remainder M x ( )
data in
×
x
n
+
sec
ondb
[
(
(
G x ( )
it
×
×
x
x
n 1
=
7
–
)
x
)
7
+
⁄
+
… lastbit
(
x
G x ( )
+
3
+
1
)
]
×
x
0
data out
NAND08GAH0A, NAND16GAH0D
AI13107