DS3170 Maxim Integrated Products, DS3170 Datasheet - Page 156

• Manufacturer Part Number: DS3170
• Description: Network Controller & Processor ICs DS3-E3 Single-Chip T ransceiver T3-E3 Fra
• Manufacturer: Maxim Integrated Products

12.6 HDLC
12.6.1 HDLC Transmit Side Register Map
The transmit side utilizes five registers.
Table 12-16. Transmit Side HDLC Register Map
12.6.1.1 Register Bit Descriptions
Register Name:
Register Description:
Register Address:
Bit #
Name
Default
Bit #
Name
Default
Bits 12 to 8: Transmit HDLC Data Storage Available Level (TDAL[4:0]) – These five bits indicate the minimum
number of bytes ([TDAL*8}+1) that must be available for storage (do not contain data) in the Transmit FIFO for
HDLC data storage to be available. For example, a value of 21 (15h) results in HDLC data storage being available
(THDA=1) when the Transmit FIFO has 169 (A9h) bytes or more available for storage, and HDLC data storage not
being available (THDA=0) when the Transmit FIFO has 168 (A8h) bytes or less available for storage.
Bit 6: Transmit Packet Start Disable (TPSD) – When 0, the Transmit Packet Processor will continue sending
packets after the current packet end. When 1, the Transmit Packet Processor will stop sending packets after the
current packet end.
Bit 5: Transmit FCS Error Insertion (TFEI) – When 0, the calculated FCS (inverted CRC-16) is appended to the
packet. When 1, the inverse of the calculated FCS (noninverted CRC-16) is appended to the packet causing an
FCS error. This bit is ignored if transmit FCS processing is disabled (TFPD = 1).
Bit 4: Transmit Inter-frame Fill Value (TIFV) – When 0, inter-frame fill is done with the flag sequence (7Eh).
When 1, inter-frame fill is done with all ‘1’s.
Bit 3: Transmit Bit Reordering Enable (TBRE) – When 0, bit reordering is disabled (The first bit transmitted is the
LSB of the Transmit FIFO Data byte TFD[0]). When 1, bit reordering is enabled (The first bit transmitted is the MSB
of the Transmit FIFO Data byte TFD[7]).
Bit 2: Transmit Data Inversion Enable (TDIE) – When 0, the outgoing data is directly output from packet
processing. When 1, the outgoing data is inverted before being output from packet processing.
Address
0AAh
0ACh
0AEh
0A0h
0A2h
0A4h
0A6h
0A8h
15
HDLC.TCR
HDLC.TFDR
HDLC.TSR
HDLC.TSRL
HDLC.TSRIE
--
--
0
7
0
Register
--
--
--
TPSD
14
--
0
6
0
HDLC Transmit Control Register
HDLC Transmit FIFO Data Register
HDLC Transmit Status Register
HDLC Transmit Status Register Latched
HDLC Transmit Status Register Interrupt Enable
Unused
Unused
Unused
HDLC.TCR
HDLC Transmit Control Register
0A0h
Register Description
TFEI
13
--
0
5
0
156 of 230
TDAL4
TIFV
12
0
4
0
TDAL3
TBRE
11
1
3
0
DS3170 DS3/E3 Single-Chip Transceiver
TDAL2
TDIE
10
0
2
0
TDAL1
TFPD
9
0
1
0
TDAL0
TFRST
8
0
0
0