XRT72L54 Datasheet, PDF (8/484 Pages) Exar Corporation – FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L54
FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
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PRELIMINARY
Figure 47. Behavior of the Terminal Interface signals between the XRT72L54 and the Terminal Equipment
(Mode 2 Operation) ............................................................................................................................. 156
FRAMER OPERATING MODE REGISTER (ADDRESS = 0X00) ..................................................................... 156
Figure 48. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input Inter-
face block of the XRT72L54 for Mode 3 (Serial/Local-Timed/Frame-Master) Operation .................... 157
Figure 49. Behavior of the Terminal Interface signals between the XRT72L54 and the Terminal Equipment
(DS3 Mode 3 Operation) ..................................................................................................................... 158
FRAMER OPERATING MODE REGISTER (ADDRESS = 0X00) ..................................................................... 159
Figure 50. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input Inter-
face block of the XRT72L54 for Mode 4 (Nibble-Parallel/Loop-Timed) Operation .............................. 160
Figure 51. Behavior of the Terminal Interface signals between the XRT72L54 and the Terminal Equipment
(Mode 4 Operation) ............................................................................................................................. 161
FRAMER OPERATING MODE REGISTER (ADDRESS = 0X00) ..................................................................... 161
Figure 52. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input Inter-
face block of the XRT72L54 for Mode 5 (Nibble-Parallel/Local-Timed/Frame-Slave) Operation ........ 163
Figure 53. Behavior of the Terminal Interface signals between the XRT72L54 and the Terminal Equipment
(DS3 Mode 5 Operation) ..................................................................................................................... 164
FRAMER OPERATING MODE REGISTER (ADDRESS = 0X00) ..................................................................... 164
Figure 54. Illustration of the Terminal Equipment being interfaced to the Transmit Payload Data Input Inter-
face block of the XRT72L54 for Mode 6 (Nibble-Parallel/Local-Timed/Frame-Master) Operation ...... 165
Figure 55. Behavior of the Terminal Interface signals between the XRT72L54 and the Terminal Equipment
(DS3 Mode 6 Operation) ..................................................................................................................... 166
FRAMER OPERATING MODE REGISTER (ADDRESS = 0X00) ..................................................................... 167
4.2.2 The Transmit Overhead Data Input Interface ........................................................................................ 167
Figure 56. Simple Illustration of the Transmit Overhead Data Input Interface block .......................... 167
TABLE 20: A LISTING OF THE OVERHEAD BITS WITHIN THE DS3 FRAME, AND THEIR POTENTIAL SOURCES, WITHIN
THE XRT72L54 IC ................................................................................................................................ 168
TABLE 21: DESCRIPTION OF METHOD 1 TRANSMIT OVERHEAD INPUT INTERFACE SIGNALS ...................... 169
Figure 57. Illustration of the Terminal Equipment being interfaced to the Transmit Overhead Data Input In-
terface (Method 1) ............................................................................................................................... 170
TABLE 22: THE RELATIONSHIP BETWEEN THE NUMBER OF RISING CLOCK EDGES IN TXOHCLK, (SINCE TXO-
HFRAME WAS LAST SAMPLED "HIGH") TO THE DS3 OVERHEAD BIT, THAT IS BEING PROCESSED ............... 171
Figure 58. Illustration of the signal that must occur between the Terminal Equipment and the XRT72L54,
in order to configure the XRT72L54 to transmit a Yellow Alarm to the remote terminal equipment .... 173
TABLE 23: DESCRIPTION OF METHOD 2 TRANSMIT OVERHEAD INPUT INTERFACE SIGNALS ...................... 174
Figure 59. Illustration of the Terminal Equipment being interfaced to the Transmit Overhead Data Input In-
terface (Method 2) ............................................................................................................................... 175
TABLE 24: THE RELATIONSHIP BETWEEN THE NUMBER OF TXOHENABLE PULSES (SINCE THE LAST OCCURRENCE
OF THE TXOHFRAME PULSE) TO THE DS3 OVERHEAD BIT, THAT IS BEING PROCESSED BY THE XRT72L54 176
Figure 60. Behavior of Transmit Overhead Data Input Interface signals between the XRT72L54 and the
Terminal Equipment (for Method 2) ..................................................................................................... 178
4.2.3 The Transmit DS3 HDLC Controller ...................................................................................................... 178
TX DS3 FEAC REGISTER (ADDRESS = 0X32) ........................................................................................ 179
TRANSMIT DS3 FEAC CONFIGURATION AND STATUS REGISTER (ADDRESS = 0X31) ............................... 179
TRANSMIT DS3 FEAC CONFIGURATION AND STATUS REGISTER (ADDRESS = 0X31) ............................... 179
Figure 61. A Flow Chart depicting how to transmit a FEAC Message via the FEAC Transmitter ...... 180
Figure 62. LAPD Message Frame Format .......................................................................................... 181
TABLE 25: THE LAPD MESSAGE TYPE AND THE CORRESPONDING VALUE OF THE FIRST BYTE, WITHIN THE INFOR-
MATION PAYLOAD .................................................................................................................................. 181
TRANSMIT DS3 LAPD CONFIGURATION REGISTER (ADDRESS = 0X33) ................................................... 182
TABLE 26: RELATIONSHIP BETWEEN TXLAPD MSG LENGTH AND THE LAPD MESSAGE SIZE .................. 182
TRANSMIT DS3 LAPD CONFIGURATION REGISTER (ADDRESS = 0X33) ................................................... 182
TABLE 27: RELATIONSHIP BETWEEN TXLAPD MSG LENGTH AND THE LAPD MESSAGE SIZE .................. 182
TRANSMIT DS3 LAPD STATUS/INTERRUPT REGISTER (ADDRESS = 0X34) ............................................... 183
Figure 63. Flow Chart depict how to use the LAPD Transmitter ........................................................ 184
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