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x0

P14

x1

P13

x2

P12

x3

P11

x4

P10

x5

P9

x6

P8

x7

P7

x8

P6

x9

P5

x10

P4

x11

P3

x12

P2

x13

P1

x14

P0

x15

INPUT

(lsb first)

AV[15]

AV[14]

AV[13]

AV[12]

AV[11]

AV[10]

AV[9]

AV[8]

AV[0]

AV[1]

AV[2]

AV[3]

AV[4]

AV[5]

AV[6]

AV[7]

bq26150

SLUS641A – JANUARY 2005 – REVISED JULY 2005

Figure 3. bq26150 Programmable CRC Hardware Implementation

The generic polynomial used in the bq26150 can be written as:

Figure 3 shows the hardware implementation of the CRC, with the corresponding bits of the authentication value

or 32768, possible CRC polynomial values. In actually, the number of possible CRC polynomial will be less than

32758 because some values, such as all 0, do not provide sufficient mixing of the results to be secure.

To authenticate a battery pack using the bq26150, the host must reproduce the CRC calculation in software. This

is done by reading the encrypted device ID and encrypted polynomial coefficients, and encrypted seed. All

values are decrypted by the host to provide the 16-bit polynomial, 16-bit seed, and 96 of the 128 bits of

calculation’s input. The CRC input is:

Device ID [95:0]

Random Challenge [31:0]

Input MSB

Input LSB

9