Rainbow Electronics DS3134 - Manual (Page 80)

DS3134
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Transmit HDLC Functions Table 6.1C
Zero Stuffing
- Only used in between opening and closing flags.
- Will be disabled in between a closing flag and an opening flag and for sending aborts and/or
interfill data.
- Disabled if the channel is set to the transparent mode.
Interfill Selection
- Can be either 7Eh or FFh.
Flag Generation
- A programmable number of flags (1 to 16) can be set in between packets.
- Disabled if the channel is set to the transparent mode.
CRC Generation
- Can be either CRC-16 or CRC-32 or none.
- Disabled if the channel is set to transparent mode.
Invert Data
- All data (including the flags & FCS) is inverted after processing.
- Also available in the transparent mode
Bit Flip
- The LSB (normal mode) of the byte from the FIFO becomes the first bit sent or the MSB
(Telecom mode) becomes the first bit sent.
- Also available in the transparent mode.
Transparent Mode
- If enabled, flag generation, zero stuffing, and FCS generation is disabled.
- Will pass bytes from the PCI Bus to Layer 1 on octet (i.e. byte) boundaries.
Invert FCS
- When enabled, it will invert all of the bits in the FCS (useful for HDLC testing).
6.2 HDLC REGISTER DESCRIPTION
Register Name: RHCDIS
Register Description: Receive HDLC Channel Definition Indirect Select
Register Address:
0400h
7 6 5 4 3 2 1 0
HCID7 HCID6 HCID5 HCID4 HCID3 HCID2 HCID1 HCID0
15 14 13 12 11 10 9 8
IAB IARW n/a n/a n/a n/a n/a n/a
Note: Bits that are underlined are read only, all other bits are read-write; default value for all bits is 0.
Bits 0 to 7 / HDLC Channel ID (HCID0 to HCID7).
00000000 (00h) = HDLC Channel Number 1 (also used for the Fast HDLC Engine on Port 0)
00000001 (01h) = HDLC Channel Number 2 (also used for the Fast HDLC Engine on Port 1)
00000010 (02h) = HDLC Channel Number 3
11111111 (FFh) = HDLC Channel Number 256