Rainbow Electronics DS31256 - Manual (Page 69)

DS31256
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7.2 HDLC Register Description
Register Name: RHCDIS
Register Description: Receive HDLC Channel Definition Indirect Select
Register Address:
0400h
Bit # 7 6 5 4 3 2 1 0
Name HCID7 HCID6 HCID5 HCID4 HCID3 HCID2 HCID1 HCID0
Default 0 0
0 0 0 0 0 0
Bit # 15 14 13 12 11 10 9 8
Name IAB IARW n/a n/a n/a n/a n/a n/a
Default 0 0 0 0 0 0 0 0
Note: Bits that are underlined are read-only; all other bits are read-write.
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 (also used for the fast HDLC engine on port 2)
00000011 (03h) = HDLC channel number 4
11111111 (FFh) = HDLC channel number 256
Bit 14/Indirect Access Read/Write (IARW). When the host wishes to read data from the internal receive HDLC
definition RAM, the host should write this bit to 1. This causes the device to begin obtaining the data from the
channel location indicated by the HCID bits. During the read access, the IAB bit is set to 1. Once the data is ready
to be read from the RHCD register, the IAB bit is set to 0. When the host wishes to write data to the internal
receive HDLC definition RAM, the host should write this bit to 0. This causes the device to take the data that is
currently present in the RHCD register and write it to the channel location indicated by the HCID bits. When the
device completes the write, the IAB is set to 0.
Bit 15/Indirect Access Busy (IAB). When an indirect read or write access is in progress, this read-only bit is set
to 1. During a read operation, this bit sets to 1 until the data is ready to be read. It is set to 0 when the data is ready
to be read. During a write operation, this bit is set to 1 while the write is taking place. It is set to 0 once the write
operation completes.
Register Name: RHCD
Register Description: Receive HDLC Channel Definition
Register Address:
0404h
Bit # 7 6 5 4 3 2 1 0
Name RABTD RCS RBF RID RCRC1 RCRC0 ROLD RTRANS
Default 0 0 0 0 0 0 0 0
Bit # 15 14 13 12 11 10 9 8
Name n/a n/a n/a n/a n/a n/a RPEN RZDD
Default 0 0 0 0 0 0 0 0
Note: Bits that are underlined are read-only; all other bits are read-write.
Bit 0/Receive Transparent Enable (RTRANS). When this bit is set low, the HDLC controller performs flag
delineation, zero destuffing, abort detection, octet length checking (if enabled through ROLD), and FCS checking
(if enabled through RCRC0/1). When this bit is set high, the HDLC controller does not perform flag delineation,