CD2481 Datasheet, PDF (141/222 Pages) Intel Corporation – Programmable Four-Channel Communications Controller

Programmable Four-Channel Communications Controller — CD2481
9.2.13
CRC Polynomial Select Register (CPSR)
Register Name: CPSR
Register Description: CRC Polynomial Select Register
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
0
0
0
0
Bit 3
0
Intel Hex Address: x’D4
Motorola Hex Address: x’D6
Bit 2
0
Bit 1
0
Bit 0
Poly
9.2.14
9.2.14.1
Bits 7:1
Bit 0
Reserved – must be zero.
Polynomial select
0 = CRC V.41 polynomial (normally used for HDLC protocol and preset to 1’s)
[x**16 + x**12 + x**5 + 1]
1= CRC-16 polynomial (generally used for Bisync but will work in HDLC mode,
preset to 0’s)
[x**16 + x**15 + x**2 + 1]
Transmit Special Mapped Characters – PPP Mode only
Transmit Special Mapped Character 1 (TSPMAP1)
Register Name: TSMAP1
Register Description: Special Mapped Transmit Character 1
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
User Defined Mapped Transmit Character
9.2.14.2 Transmit Special Mapped Character 2 (TSPMAP2)
Intel Hex Address: x’1B
Motorola Hex Address: x’18
Bit 1
Bit 0
Register Name: TSMAP2
Register Description: Special Mapped Transmit Character 2
Default Value: x’00
Access: Byte Read/Write
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
User Defined Mapped Transmit Character
Intel Hex Address: x’04
Motorola Hex Address: x’07
Bit 1
Bit 0
Datasheet
141