SH32F2601PSLASH032PR datasheet(82/370 Pages) SINOWEALTH

82 / 370 page

SH32F2601

12.

CRC Calculation Unit

12.1

Introduction

The CRC (cyclic redundancy check) calculation unit is used to get a CRC code from an 8/16/32-bit data and configured

polynomial. Among other applications, CRC-based techniques are used to verify data transmitting or storage integrity. In the

scope of the EN/IEC 60335-1 standard, they offer a means of verifying the Flash memory integrity. The CRC calculation unit

helps compute a software signature during runtime, to be compared with a reference signature generated at link-time and

stored at a given memory location.

12.2

Main Features

 Supports various CRC polynomial

(1) CRC-32: ( 0x04C11DB7)

Polynomial:

(2)

CRC-16: (0x8005)

Polynomial:

(3) CRC-CCITT: (0x1021)

Polynomial:

(4) CRC-8: (0x7):

Polynomial:

 Provides CRC_INIT register to define first data in data register. When calculating CRC-16, the lower 16 bits of

CRC_INIT are valid. When calculating CRC-8, the lower 8 bits of CRC_INIT are valid.

 Configurable input/output data conversion, includes byte reversal, bit reversal in byte, and 1’s complement (bitwise

NOT).

 Supports 8/16/32-bit data input. If intput data is 8-bit then 8-bit data will be calculated. If intput data is 16-bit then 16-bit

data will be calculated. If intput data is 32-bit then 32-bit data will be calculated. The bits of intput data is independent

of the CRC format. The atom unit for calculating data is 8-bit, so if multi-byte data inputted, low byte in order will be

calculated first.

 CRC-8 computation done in 1 clock cycle, CRC-16 computation done in 2 clock cycles, CRC-32 computation done in 4

clock cycles .

12.3

Function Description

When calculating CRC, CRC_CR is firstly set according to the actual application. Then polynomial and CRC initial values

required are set. After setting, RELOAD@CRC_CR needs to be written to ‘1’ to load the initial value into the CRC_DR register.

Then register CRC_DR can be written to calculation and be read to get the result

When writing, 8-bit, 16-bit and 32-bit data are allowed, but word alignment is required when writing/reading (4-byte

alignment, which means it must be the address of CRC_DR), otherwise the result is unpredictable. Each write operation into the

data register creates a combination of the previous CRC value and the new one. Therefore, when the input conversion is set to

all 0s (which means no conversion is performed before written to data register), the CRC results obtained by writing

0x12345678 once and continuously writing 0x78, 0x56, 0x34, 0x12 are the same.

SH32F2601P/032PR bảng dữ liệu(PDF) 82 Page - SINOWEALTH Electronic Ltd

SH32F2601P/032PR bảng dữ liệu(HTML) 82 Page - SINOWEALTH Electronic Ltd

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

bảng dữ liệu tải về

Link URL