Purpose This document illustrates outlines T8208 accomplishes add
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CelXpresT8208 UTOPIA Address Polling Routine
Purpose
This document illustrates outlines T8208 accomplishes address polling scheme both transmit receive sides UTOPIA Level specification. polling function specific this chip uses round-robin technique acquiring fair system multiple physical layer (MPHY) polling. T8208 device support total multiple PHYs (MPHY).
UTOPIA
Note: Consistent with UTOPIA specification, terms transmit receive always referenced with respect asynchronous transfer mode (ATM) mode operation T8208. word should mentioned regarding UTOPIA throughput both transmit (TX) UTOPIA receive (RX) UTOPIA directions operating both 8-bit 16-bit UTOPIA. general information, UTOPIA mode uses clock cycles process cell 8-bit UTOPIA. seven extra cycles being used shared UTOPIA purposes present regardless 8-bit/16-bit modes. UTOPIA mode uses clock cycles process cell 8-bit UTOPIA. extra cycles being used shared UTOPIA purposes present regardless 8-bit/16-bit modes.
UTOPIA Throughput
8-Bit UTOPIA bits bytes Mcycles (MHz) 1cell 353.33 Mbits/s byte cell cycles 16-Bit UTOPIA bits bytes Mcycles (MHz) 1cell 635.29 Mbits/s byte cell cycles cycles
(eq. (eq.
UTOPIA Throughput
8-Bit UTOPIA bits bytes Mcycles (MHz) 1cell 359.32 Mbits/s byte cell cycles 16-Bit UTOPIA bits bytes Mcycles (MHz) 1cell 654.55 Mbits/s byte cell cycles cycles
(eq. (eq.
CelXpres T8208 UTOPIA Address Polling Routine
User Notes
Before starting, aware that this application note does address shared UTOPIA polling mode T8208. further assistance with shared UTOPIA functionality needed, T8208 data sheet (DS01-295DLC September 2001) should consulted. This document presented separate sections titled outgoing Amode (transmit) incoming Amode (receive). This document also general application note T8207 T8208 devices. What applies T8208 using MPHYs 8-bit UTOPIA mode, applies T8208 using MPHYs 16-bit UTOPIA mode T8207 using MPHYs 8-bit UTOPIA mode. Table T8207/T8208 Options Device UTOPIA Mode MPHYs 8208 8208 8207 8-bit 16-bit 8-bit Addrs. CLAVs
Naming Conventions
example below shows MPHY CLAV number address. MPHY[0F] ADDRESS
CLAV NUMBER
MPHY always followed first CLAV number then address hex: number corresponds CLAV number. letter corresponds address. MPHY[0F] combination CLAV address [F].
Document Terminology
UTOPIA-Refers UTOPIA Level Specification (AForum AF-PHY-0039.000) unless otherwise noted. Snapshot-An 8-byte location memory that uses locations represent requests physical layer (PHY) devices that asserted cell available (CLAV) signal during address polling routine indicating they have data transmit. snapshot memory bits shown Table Each (0-63) corresponds MPHY (0-63) with indicating service request indicating service request. Table Snapshot Mapping/CLAV[x] CLAV[x] Bits/Snapshot 00-0F 10-1F 20-2F 30-3F
Agere Systems Inc.
CelXpres T8208 UTOPIA Address Polling Routine
Introduction
MPHYs
T8208 resides UTOPIA data services MPHYs when Amode. Traffic delivery through these MPHYs managed through UTOPIA interface. T8208 will support total MPHYs using addresses four CLAVs 8-bit mode, total MPHYs using eight addresses four CLAVs 16-bit mode. T8207 will support total MPHYs using addresses CLAVs 8-bit mode. polling implementation uses sequential roundrobin scheme incrementing through addresses UTOPIA. This polling function assisted with logic from four CLAV signals support total MPHYs. polling process, specific CelXpres products, fixed programmable. logical MPHYs, shown left side Figure ranging from 00-3F, MPHYs that supported addresses CLAV signals. MPHY responds polled address asserting CLAV signal, indicating cell send space receive cell). When CLAV[x] asserted specific address, logic will corresponding snapshot. This snapshot table will used later send/receive data to/from MPHYs that were triggered during polling cycle (0-F). When address onto address line four CLAVs respond, associated bits snapshot same clock cycle. After polling cycle completes (0-F), successive cycles begin, more MPHY addresses snapshot until completely emptied. This safeguard installed prevent repeat entries.
T8208 DATA ADDRESS MPHYs CLAV[0] 00-0F
ADDR
ENB[0]*
CLAV[1] ADDR ADDR ENB[2]* CLAV[2] ENB[1]*
10-1F
20-2F
30-3F ADDR ENB[3]* CLAV[3]
2423(F)
Figure Block Diagram MPHY Connections Snapshot Memory
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CelXpres T8208 UTOPIA Address Polling Routine
Introduction (continued)
Figure shows mapping between CLAV[x] signal MPHY address corresponding snapshot MPHY address. most important component understand snapshot service priority flow. arrow center drawing illustrates that positions MPHYs) polled sequence from This memory mapping MPHYs same transmit receive modes. priority CLAV based sense that MPHYs associated with CLAV[0] serviced prior those associated with CLAV[1] etc. Figure illustrates this concept.
CLAV
MPHY SNAPSHOT ADDRESS POS. MPHY ADDR
SNAPSHOT SERVICE PRIORITY HIGHEST
LOWEST
MPHY SNAPSHOT CLAV ADDRESS POS. MPHY ADDR
2424(F)
Figure CLAV MPHY Address Snapshot Memory with CLAV Priority Servicing
Agere Systems Inc.
CelXpres T8208 UTOPIA Address Polling Routine
T8208 Polling UTOPIA Level Polling Implementations
UTOPIA polling left open design device designers explicitly defined UTOPIA specification; hence, device different polling scheme than another between chip manufacturers. UTOPIA Level address polling diagrams show example polling process that randomly selects addresses (Figure whereas T8208 uses sequential round-robin polling (Figure order which enable (ENB*), CLAV, start cell (SOC) signals occur critical comply with AForum UTOPIA specification, T8208 demonstrates this Figure
SELECTION POLLING: POLLING POLLING
TxCLK
TxADDR
TxCLAV
TxENB*
TxDATA
TxSOC
CELL TRANSMISSION
MPHY
MPHY
2425(F)
Figure UTOPIA Specification Polling Example
POLLING:
POLLING
POLLING
TxCLK
TxADDR
TxCLAV
TxENB*
TxSOC
2425.a(F)
Figure T8208 Transmit Polling Example (CLAV[0] Only) Triggered ENB*, with PHYs
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CelXpres T8208 UTOPIA Address Polling Routine
transmitted received data always starts same clock cycle assertion. Again, polling accomplished during cell transfer same round-robin polling technique used accomplish fair polling. achieve MPHY polling, T8208 sequentially polls logical addresses uses four discrete CLAV signals. conceptual mechanical illustration shown Figure page illustrates internal address polling function T8208. transmit timing diagram shown Figure
Outgoing AMode (Transmit)
Alayer responsible supplying clock MPHY layer synchronize devices. stated UTOPIA specification, rising edge TxClk, Atransmit device generates output signals samples input signals. rising edge TxClk used both Aand MPHY layers sample generate signals.
TRANSMIT CYCLES
SELECT
CLAV
ADDRESS
ENB*
DATA
2427(F)
Figure Transmit Timing Diagram UTOPIA side, asserted more than clock cycle after ENB* asserted, ignored, SOC_err (0102h) set, entire frame clock cycles which ENB* given ignored. (See UTOPIA specification data sheet more details).
Agere Systems Inc.
CelXpres T8208 UTOPIA Address Polling Routine
array MPHY addresses above arrow, contains asserted CLAVs through last polling cycle. Note: snapshot will wait status bits clear from last polling cycle before adding status bits, thus allowing transmission data complete MPHYs that were CLAVed during initial polling. Figure demonstrates polling mechanism behaves transitions from address address.
Outgoing AMode (Transmit)
(continued)
Order Operation
Incrementing through MPHY addresses, necessary find CLAV signals that asserted during null address time (directly following polled address). snapshot which, represented
CLAV[0] CLAV[0] ADDRESS ADDRESS START STOP
SHOT
CLAV[0] CLAV[0] ADDRESS CLAV[0] ADDRESS ADDRESS START STOP
CLAV[0] ADDRESS
ADDRESS
ADDRESS
ADDRESS
CLAV[0]
CLAV[0]
CLAV[0]
CLAV[0] ADDRESS
ADDRESS CLAV[0] ADDRESS CLAV[0]
ADDRESS CLAV[0]
ADDRESS CLAV[0] ADDRESS CLAV[0]
ADDRESS CLAV[0]
START POLLING CYCLE
STOP POLLING CYCLE
2428(F)
Figure UTOPIA MPHY Polling Example Using CLAV
Agere Systems Inc.
CelXpres T8208 UTOPIA Address Polling Routine
Since CLAV[0] address asserted, there cells send status (snapshot position set, indicating that MPHY[01] would like request service. CLAV[0] address combination shown Figure After setting MPHY[01] status snapshot CLAV[0], remaining CLAVs checked MPHY[11], MPHY[21], MPHY[31] asserted other CLAV groups. They asserted; therefore, they have cells send will their status snapshot. pointer will advance next address. more CLAVs asserted until address MPHY[14] will appear snapshot memory setting snapshot position that serviced future following service MPHY[01], which last status snapshot. MPHY[2F] represented same fashion setting snapshot position seen Figure
Outgoing AMode (Transmit)
(continued)
Conceptual Example Three Different MPHYs with Three Different CLAVs
Consider polling cycle with MPHYs snapshot, current MPHY being serviced MPHY[08]. state system shown Figure Data MPHY[08] will sent during polling cycle. suppose that MPHY[01], MPHY[14], MPHY[2F] have single CLAV signal that asserted. remaining MPHYs have cells available, their CLAVs equal pointer going start polling from address that CLAVs asserted pointer moves address reports which CLAV signals were set.
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS START STOP
SHOT
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS START STOP
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS
ADDRESS
SERVICING ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3]
SERVICING ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3]
2429(F)
CLAV[0] CLAV[1] CLAV[2] CLAV[3]
2430(F)
Figure Initial Polling State
Figure Ending Polling State
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CelXpres T8208 UTOPIA Address Polling Routine
Since data still transit polling suspended remainder this current cell transmission, there need line transmission cell data that polling timing. make this happen, address lines pulled high null address [1F] inserted. sequence will resemble Figure Four clock cycles before cell completed data transmission, T8208 will again poll MPHY that actively being serviced check last time there more cells left transmit (see clock cycle Figure there cells still waiting processed that specific MPHY, will granted request. single MPHY, therefore, cannot serviced more than times given polling sequence preserve fairness. MPHY that currently being serviced will always receive highest priority next available service opportunity event that CLAV accidentally accounted for. This polling will allow backto-back cell transmission there only MPHY that requesting service. example, MPHY[08] being serviced during polling process MPHY[08] asserts CLAV transmission/receive sequence indicating more cells, MPHY[08] will serviced again.
Outgoing AMode (Transmit)
(continued)
Conceptual Example Three Different MPHYs with Three Different CLAVs
(continued) After having exhausted addresses (0-F) first pass through, pointer will wait halt polling cycle until next cell transmission. snapshot contains MPHY locations MPHY[01], MPHY[14], MPHY[2F] will service them that order until snapshot empty. transmission data still occurring MPHY[08] which started when asserted. This example illustrated polling operates when using three separate CLAV signals three separate addresses. next example will show polling accomplished using different addresses CLAV signals set.
POINTER STOPS HERE DOES REPEAT SEQUENCE, INSTEAD FILLS SPACE WITH NULL ADDRESSES
LAST POLLING ATTEMPT MPHY BEING SERVICED EVENT THERE STILL MORE DATA
2431(F)
Figure Cell Transmission Address Line Values
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CelXpres T8208 UTOPIA Address Polling Routine
example, MPHY[08] being serviced during polling process MPHY[08] asserts CLAV transmission/receive sequence indicating more cells, MPHY[08] will again serviced.
Outgoing AMode (Transmit)
(continued)
Conceptual Example MPHYs Each with Four CLAVs
Consider example where there addresses that respond four CLAVs. addresses interest PHY[4] PHY[F]. four CLAVs asserted each address, snapshot memory will look something like Figure Using T8208 polling technique, snapshot loaded with following bits, shown Figure When address four CLAVs noticed corresponding bits snapshot memory, indicating MPHY[04], MPHY[14], MPHY[24], MPHY [34] request service. that T8208 approaches servicing these MPHYs CLAV sorting, where service starts with CLAV[0] (ADDRESS[0]-ADDRESS[F]) goes CLAV[3] (ADDRESS[0]-ADDRESS[F]) shown Figure page Service these MPHY devices will granted from left right CLAV priority) will only given these devices since they were only ones respond during polling cycle. This memory will accept further writes until very last MPHY this case MPHY [3F]) serviced completely, that time polling cycle will start taking service requests.
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS START STOP
CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS
SERVICING ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3] ADDRESS CLAV[0] CLAV[1] CLAV[2] CLAV[3]
2432(F)
Figure Start/Ending Polling State
START 00-0F (CLAV[0]) 10-1F (CLAV[1]) 20-2F (CLAV[2]) 30-0F (CLAV[3])
2433(F)
Figure Snapshot Memory
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CelXpres T8208 UTOPIA Address Polling Routine
Incoming AMode (Receive)
UTOPIA side, asserted more than clock cycle after ENB* asserted, ignored, SOC_err (0102h) set, entire frame clock cycles which ENB* given ignored. (See UTOPIA spec data sheet more details.) data that being transmitted received always starts same clock cycle assertion. Again, polling accomplished during cell transfer same round-robin polling technique used accomplish fair polling done transmit. achieve MPHY polling, T8208 sequentially polls addresses uses four discrete CLAV signals. polling operation identical that transmit with exception timing (see Figure 12). conceptual mechanical illustration shown below illustrates internal address polling function T8208. receive timing diagram shown below Figure
RECEIVE CYCLES
SELECT CLAV
ADDRESS
ENB*
DATA
CYCLES CYCLES)
2434(F)
Figure Receive Timing Diagram
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additional information, contact your Agere Systems Account Manager following: INTERNET: http://www.agere.com E-MAIL: docmaster@agere.com AMERICA: Agere Systems Inc., Union Boulevard, Room 30L-15P-BA, Allentown, 18109-3286 1-800-372-2447, 610-712-4106 CANADA: 1-800-553-2448, 610-712-4106) ASIA: Agere Systems Hong Kong Ltd., Suites 3201 3210-12, 32/F, Tower Gateway, Harbour City, Kowloon Tel. (852) 3129-2000, (852) 3129-2020 CHINA: (86) 21-5047-1212 (Shanghai), (86) 10-6522-5566 (Beijing), (86) 755-695-7224 (Shenzhen) JAPAN: (81) 3-5421-1600 (Tokyo), KOREA: (82) 2-767-1850 (Seoul), SINGAPORE: (65) 778-8833, TAIWAN: (886) 2-2725-5858 (Taipei) EUROPE: Tel. (44) 7000 624624, (44) 1344
Agere Systems Inc. reserves right make changes product(s) information contained herein without notice. liability assumed result their application. CelXpres trademark Agere Systems Inc.
Copyright 2001 Agere Systems Inc. Rights Reserved
November 2001 AP01-061DLC
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