Fujitsu FR81S Manuale Utente

CHAPTER 38: CRC 

 

 

5. Operation 

 

FUJITSU SEMICONDUCTOR LIMITED 

 : CRC 

FUJITSU SEMICONDUCTOR CONFIDENTIAL 

18 

Example 1 CRC16 and fixed byte input are shown below. 

Figure 5-2 Example 1 

 

//**************************************** 

// CRC16 (CRC ITU-T) 
// polynomial: 0x1021 
// initial value: 0xFFFF 

//  CRCCR.CRC32:  0 // CRC16 
// CRCCR.LTLEND: 0 // big endian 
// CRCCR.LSBFST: 0 // MSB First 

// CRCCR.CRCLTE: 0 // CRC big endian 
// CRCCR.CRCLSF: 0 // CRC MSB First 
//  CRCCR.FXOR:   0 // CRC Final XOR off 

//**************************************** 
 
// 

// Example 1-1 (Byte-unit writing) 
// 
 

// Initialization 
B_WRITE (CRCCR, 0x01); 
 

// data write "123456789" 
B_WRITE (CRCIN, 0x31); 
B_WRITE (CRCIN, 0x32); 

B_WRITE (CRCIN, 0x33); 
B_WRITE (CRCIN, 0x34); 
B_WRITE (CRCIN, 0x35); 

B_WRITE (CRCIN, 0x36); 
B_WRITE (CRCIN, 0x37); 
B_WRITE (CRCIN, 0x38); 

B_WRITE (CRCIN, 0x39); 
 
// read result 

H_READ (CRCR+2, data); 
 
// check result 

assert (data == 0x29B1); 
 
// 

// Example 1-2 (CRC check) 
// 
 

// Initialization 
B_WRITE (CRCCR, 0x01); 
 

// data write "123456789" + CRC 
B_WRITE (CRCIN, 0x31); 
B_WRITE (CRCIN, 0x32); 

B_WRITE (CRCIN, 0x33); 
B_WRITE (CRCIN, 0x34); 
B_WRITE (CRCIN, 0x35); 

B_WRITE (CRCIN, 0x36); 
B_WRITE (CRCIN, 0x37); 
B_WRITE (CRCIN, 0x38); 

B_WRITE (CRCIN, 0x39); 
B_WRITE (CRCIN, 0x29); // <-- CRC 
B_WRITE (CRCIN, 0xB1); // <-- CRC 

 
// read result 
H_READ (CRCR+2, data); 

 
// check result 
assert (data == 0x0000); 

(The following is assumed)

B_WRITE -- Byte writing

H_WRITE -- Half-word writing

W_WRITE -- Word writing

B_READ -- Byte reading

H_READ -- Half-word reading

W_READ -- Word reading

CRCCR

-- Control register address

CRCINIT -- Initial value register address

CRCIN

-- Input data register address

CRCR

-- Current CRC register address

3

1

3

2

3

3

3

9

Image of input order

into CRC calculator

MSB

LSB

MN705-00010-1v0-E

1287