TLE5010 Datasheet, PDF (43/56 Pages) Infineon Technologies AG – GMR Based Angular Sensor

TLE5010
Draft
10.1
CRC Generation
Data Communication via SSC
• This CRC is according to the J1850 Bus-Specification of 15.Feb.1994 for Class B
Data Communication.
• Every new transfer resets the CRC generation.
• Every byte of a transfer will be taken into account to generate the CRC (also
the sent command(s)).
• Generator Polynom: X8+X4+X3+X2+1, for the CRC generation the fast CRC
generation circuit is used. (See Figure 13)
• The remainder of the fast CRC circuit is initial set to ’11111111_B’.
• Remainder is bit inverted before transmission.
Figure 13 shows the fast CRC Polynom.
The zero extension for initial CRC calculation is included!
Input ^{xor & 1 1 xor 1 xor 1 xor 1 1 1 1}
TX_CRC
X0 X1
X2
X3
X4 X5 X6 X7
Figure 13
parallel Remainder
Fast CRC polynomial division circuit
Serial
CRC
output
10.2
Slave Active Byte Generation
The position of the ’0’ in a nibble corresponds to the given slave number.
The slave active byte (cccc_nnnn) is made up of a
• low nibble (nnnn). One ’0’ is generated always according to the slave number.
• high nibble (cccc). The ’0’ is only generated, if the readback CRC is correct.
Slave1: S_NO = 0 Ö bit 0 is pulled low Slave Active Byte: 1110_1110
Slave2: S_NO = 1 Ö bit 1 is pulled low
Slave3: S_NO = 2 Ö bit 2 is pulled low
Slace4: S_NO = 3 Ö bit 3 is pulled low
Slave Active Byte: 1101_1101
Slave Active Byte: 1011_1011
Slave Active Byte: 0111_0111
Example for a communication disturbed by other bus participants:
Slave1: S_NO = 0 Ö bit 0 is pulled low, but the high nibble remains as ’1111’.
> Slave Active Byte: 1111_1110
Preliminary Data Sheet
43
V 0.9, 2007-05