FXLS93421 datasheet(206/254 Pages) NXP

206 / 254 page

NXP Semiconductors

FXLS9xxxx

Dual channel inertial sensor

4. If the shift register contains all zeros, the CRC is correct.

5. If the shift register contains a value other than zero, the CRC is incorrect.

The CRC polynomial and seed are shown in Table 319.

SPICRCSEED[3:0]

Default polynomial

Default non-direct seed

0000

x8 + x5 + x3 + x2 + x + 1

1111 1111

Non-Zero

x8 + x5 + x3 + x2 + x + 1

1111 SPICRCSEED[3:0]

Table 319. SPI command message CRC

Some example CRC calculations are shown in Table 321.

14.4.1.2 Response error checking

The device calculates a CRC on the entire 32-bits of each response. Message data is

entered into the CRC calculator MSB first, consistent with the transmission order of the

message.

The CRC Encoding procedure is:

1. A seed value is preset into the least significant bits of the shift register.

2. Using a serial CRC calculation method, the transmitter rotates the transmitted

message into the least significant bits of the shift register, MSB first.

3. Following the transmitted message, the transmitter feeds eight zeros into the shift

4. When the last zero is fed into the input adder, the shift register contains the CRC.

5. The CRC is transmitted.

The CRC polynomial and seed are shown in Table 320.

SPICRCSEED[3:0]

Default polynomial

Default non-direct seed

0000

x8 + x5 + x3 + x2 + x + 1

1111 1111

Non-Zero

x8 + x5 + x3 + x2 + x + 1

1111 SPICRCSEED[3:0]

Table 320. SPI CRC polynomial and seed

Some example CRC calculations are shown in Table 321.

Bits[31:28]

Bits[27:24]

Bits[23:16]

Bits[15:8]

Bits[7:0]

Polynomial

Seed

Command

0x0

8-bit CRC

x8 + x5 + x3 + x2 + x + 1

1111 1111

0x8

0x0

0xBD

x8 + x5 + x3 + x2 + x + 1

1111 1111

0x4

0x0

0x57

x8 + x5 + x3 + x2 + x + 1

1111 1111

0xC

0x0

0x66

x8 + x5 + x3 + x2 + x + 1

1111 1111

0x6

0x0

0xB8

x8 + x5 + x3 + x2 + x + 1

1111 1111

0x4

0x0

0xE5

x8 + x5 + x3 + x2 + x + 1

1111 1111

0xC

0x0

0x13

x8 + x5 + x3 + x2 + x + 1

1111 1111

0x6

0x0

0x0A

Table 321. SPI 8-bit CRC calculation examples

FXLS9xxxx

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Product data sheet

Rev. 6 — 8 February 2021

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