SCI Systems, Inc. 5242500 ARINC 629 CURRENT MODE COUPLER (CMC) DOOO Current Mode implementation of ARINC 629 Interfaces To SCI Serial Interface Module (SIM) (5242300) Supports Stub Lengths to 40 Meters High Speed Operation (Transmit P, < 50 nsec) GENERAL OVERVIEW The 5242500 Current Mode Coupler (CMC) provides the interface between tbe Serial Inverface Mocdube (SIM - SCT S242300) and the ARINC 629 current mode commurni- cations bus. The CMC includes dual ransmit and receive channels, channel selection control, bus shunt circuitry, anda receive only" mode of operation. Figure 2 isa block diagram representation of the CMC's functional units. Each transmitreceive channel in the CMC consists of a bus. driver and a rans not amplifier. The bus driver is reaspomeibbe for doubled transmission onic the curren mode dais bus while the impedanos amplifier imineters bus doublets tothe stub cable. The CMC's channel selection circuiury monitors the doublet polaricy received from the SIM via the stub imerface and enables the corresponding channel, The CMC's shunt circuitry presents a low impedance load to the current mode bus under power-on and power-off conditions. The CMC provides receive only mle of operation where both iminsmit channels are disabled. The receive-only mode is devermined by the polarity of the pewer lines supplied by the STM. L/95sc I 5242500 ick TRANSMIT | DATA BUS INTERFACE RECEIVE DATA BLES INTERFACE Figure 2. CMC Block Distram s Sos aba Ts = TRANSIT STA Tse _ i INTERFACE & T u =] POWER CONTROL ! Pl T E 2 AECERE F ee A - STUB t ASB <q| INTERFACE cones, OPERATION The CMC is ased inconjomction with the SIM bo ineeriacs a Terminal Comrolles to ihe ARINC 629 curren mode ita bus. A five conductor conmector, Bocing Standard BACC 6308 10-055, provides the coupber interface wo the stub cable, utilizing the pin out configuration shire in Figure 3 and the pin descriptions listed in Table 1. Trier) coupler shields are decinically connected to the inside portion of ibe stub interface connmector's body. The retum for the CMC's internal shield is then provided through the circumferential connection of the conneciog plug to it mating backshell, Sunbank SE0ILIFIOMW?. The CMC is magneticully coupled to the curren mole daa bas by two individual inane fonmers: one being transmit and the other receive. The bos iranshormers are comprised of winkings and bo ferrite E-cores which encompass the curren mode data hos cable when the coupler i instalbed, ORTEPHAL S60 U0 GOnAnCTS Th Goh MDC TO Dey Figure 3, CMC Connector Pinout Table 1. Coapler Pin Description PIN | PIN SAME lo FUNCTION ] TSh [ TVTREASSMIT STUE E Z TSA I TRANSMIT STUB A - TSA & TSH inierface meeereoe doubles from SOM Bor daia bos iranemis- gona Well as common mode volluge for coupler power. 3 Nyt? Tan (Cisne RS. o RECEIVE STUN & 5 RSA O | RECEIVESTUR A- RSA & RS interface aepplies daca bees raf fee wo the SIM and received samme mods voltage for coupler peer, Body CIRCUM, 0 CIRCUMFERENTIAL GROUND - Ground reference coppiced from the: 514i etilized for the OND (CMOC peed shichd eclur. Conecction 1 made cacumfercniially lo ihe mating beckabsll, 156.Sci TRANSMIT DATA TRANSFER The Curent Mode Coupler receives voltage mode dou- bles fram the S04 anal converts them bo current mole dowhbets whichare then ranamitted onto the data bos. The vollage mode double receneed by the CMC is a halancel differcntial signal measured between TSA and TSB of the slub cable (Pig. 4), The stub double consists of a 624 namnsecond with: pubes bollkiwed by an ideniecal pulse of the opposite policy. Bach stwhdevables hald-pulse attains adiffercnual peak ampli of approaimately 45 volts, RECEIVE DATA TRANSFER The Cument Mod: Coupler neasciver necees cumeni moke doubles frown the data bus (Fig. 6) and converts them io differential voltage mode sub doublets (Fig, 7) for Iransmison bo the SIM. Each receiver channel consists of a imnsimpedance amplifier with a fixed dif- ferenial gain of 60) 22 andl butters wedrive che stub reece lines, RSA & RSE, The receiver channel that os COUPLER POWER MODES Bower lo ihe Cunment Moke Coupler is supplied by the SIM vin the common mode vollages on ihe sub inderfaces TSA/TSB and RSA/RSB. The two modes of coupler Opcriien are the iansmitfrecelve" and neecive only" mode. The SIM controls the coupler mode of operation through the polanity of the common mode voltages. The: coupler trinamireceeive mode 1 enabled when the TSA/TSE common mote voltage supplies +154 anal COUPLER CHANNEL CONTROL Channel selectioa for the CMC is devermined by ihe sbuhh doublet polarity on ihe TSA/TSB lines. The coupler defaults lo channel "AC upon initial povosr- up cone Lice, The coupler channel central circuitry monitors the pelanty of the stub imunsnmit doublet bo determine the active channel. The "A" channel is enabled when the ELECTRICAL SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS* Case Temperature... AC to +84C Siomge Temperiure ....... UNC ta #8 FC Voltage on Any Pin with Respect io Cinanel ....... en 4-25 Power Dissipation ~....-..-...:2.0:.ccccinosess a D.C, CHARACTERISTICS T, = -40PC to +85 5242500 The CMC transfers cach stub doublet half excursion bo lhe current made dala bus as a nominal SmA peak signal (fig. 5). The coupler transmit circuitry limits the maxi- mum slew rate of whe data but dowhler wo 2 Asus, Bus load impedance reflected to ihe dota bus by ihe transmit driver is minimined via on board shunt comme circuitry. The shunt windings of the transmit Gore present a low Impedance load to the data bus when the transmia drivers arc hnachive or disabled (power dovnreceive enly), bo be used for doubled recep 1s determiner! iby the coupler channel contral circuitry. The channel control circubiry dictates the active und inactive channel by sup plying power caly to the chasen roseiner channel, The moe ee Impedance prescnits a low impedance bo thie: data but dung normal operation (0.0542) ane during coupler perever of Dconkkition (00, (2) BSAJRSB common moe vollage supplies -1SV. When in he tminsmilreecive mode, ihe coupler maintains one branemt and receive channel. The coupler receive only mode is aimed when the SIM supplics +15V comim, mole on REAJRSR and -13V 0 ceammon mole on TSA/TSB, [nthe receiveonly mod: both coupler iramsmit channels are powered down and one coupler receiver channel is active. leading dkwblet hall is posiive as measured from TSA bi TSB. When ihe beading dowblet half is megative, channel AY isdisailed and channel B" is enabled, The coupler allows the SIM to control channel selecuion in uans- milreseive moke only, "Notes: Sinsses above these listed wonder Abele Maximum Rating may cause permanent) damage to ihe device. This is a stress rating only and functional oper- aition of the deviog ut these orany oiber condivions above those imdicaied in ihe operntions sections of this specication aire neat implied, Exposure toe absolute maximum rating conditions for extended periods may affeca deviee reliability. POWER REQUIREMENTS Symbol Parameter Min | Max Lint Tst Conditions ae Supply Current (+15,-15) Continuous Transmit Transmit 290) mA, |\Wors! Case 2MHz Man- o Receive 66 mA, | chester Data Standby 55 IMAL ra Vou | Supply Voltage - Transmit 24.6) 37.5 V Minimum and Maximum Bus DoubletSci D.C. CHAR 5242500 ACTERISTICS T, = 40C ta 489C TRANSMIT Symbal Parameter Min | Typ | Max | Unit Test Conditions We, | Stub Input Voltage - Posilive Peak 30 | 45 | 5.2 Y |TSA- TSB (Fig. 4) Differential Vs, | Stub Input Voltage - Negalive Peak | -5.2 | -4.5 | -3.0 | V |TSA-TSB (Fig. 4) Citterential Vie | Transmit Stub Common Mode #13.5 | +15.0/4+15.5) V | Transmit Mode Voltage 15.5 |-15.0)-125] V | Receive Only io Transmit Stub input impedance 110 th Zar | Bus Input Impedance - Transmit Cail 0.25 | o | Power On 0.24 | 2 | Power OF Zan Bus Input impedance - Receiva Coll 0.05 Oo | Power On 0.03 | & | Power Off Vow, | Stub Receive Quiput Voltage -Posi- | 1.35 | 3.0 | 348 | Vo | AeceWer Gain = tive Peak (Fig. 7) 60 mvs Veq | Stub Receive Cuipul Voltage -Nega-| -3-48) -3.0 | -1.35 |) Vo | Receiver Gain = tive Peak (Fig. 7) BO mvirrA, Vase | Receive Stub Common Mode Vorll- 15.5) -15.0) 13.5) Vo | Transmi Mode age 13.5) 4+15.0)4155] Vo | Receive Only Ze, | Stub Load Impedance (ASA - ASB) 100 {2 | Stub Cable Characteris- lic: Impedance Z Bus Receive Transimpedance 55.5 61.2 | Ohm 5 tren = | Receive Propagation Delay - Bus to 2] nS Stub A.C. CHARACTERISTICS T, = 40C to 48C Symbol Farameter Min Max Limits Test Conditions t Rise Ta, +] SA bo +35enA 6.6 18 ns Mote 1.2.2 igi det kobe width, +S5mA 25 TS ns Mabe 1,23 et Ist lobe width, #13mA Sd 95 ns Mote 12.3 4a 181 abe width, +42mA4 20 75 ns Note 1,23 ech 2nd lobe width, 2k a 74 na Mose 1,24 fe 2nd lobe width, - 104 Sa HE ns Note 12,5 Lar 2nd lobe gucpedanon, he mul, 2) 7 fe Noe 12,3 i Fall dime, -35m4 io - 13k 6 a0 Tks Node 12,3 L Tetal Width [412 m4 to - 13 mA) Et lke nek Note 12,3 ie ist lobes Maximum aa tt mA Node 12,3 Eg 2nd Lobe Maximum 43 6 mA Now 12.3 tea Transmit Propagation Delay - Stub 5th ns io Bus lean Channel Svaich Belay 250 nS 1 References to +,positive and "-.negative" are relative only to each lobe of the doublet. Ist labe may be positive or negalive. 2 Single tu ri bus, 260 0 4 Case temperature -40C to 485C. All specified operating conditions. 4 13sReceive Tee The SIM receives voltage doublets from the coupler as they are picked up from the twisted pair data bus as current doublets. Although the couplerrecelver isan active amplifier, it has a fixed gain. Therefore, the amplitude of the doublet received by the 51M from the coupler is indicative of the bus doublet amplitude. It is this feature, along with the fact that the coupler receives its own transmit onte the data bus, that allows the SIM to perform data bus signal analysis of its own transmitted signal. (See Fault Management & BITE). The 5IM ana- lyzes each incoming doublet and checks the signal for the proper waveform symmetry and amplitude. The accept- able amplitude is determined by whether the signal was a result of the couplers own transmit of whether it was data from a distant terminal. The receive doublets from distant terminals are required to satisfy one of two amplitudes depending on the status of 5242300 the CTHA & CTHB control lines. This allows for those ARINC 629 systems with few couplers and shorter bus lengths to be configured for higher noise immunity. In order to reduce delays in the data translation and transfer function the SIM regenerates the Manchester biphase data transition tothe Terminal Controller as soon as the incoming dowblet is detected. Should the doublet turn out to be defective or emoncous the SIM will suppress the next two transitions of the incoming Manchester data. The Terminal Con- troller will detect that the transitions have been suppressed. The SIM determines the end of a message on the twisted wire data bus by counting four (4) consecutive rising edges of RACK clock without the receipt of a doublet from the coupler. The SIM will then assume a bus quiet condition (RXI & RAN low). Fr erro 1 oy = H oe eS i Figure 4, 5242300 SIM Receive Doubleta AMPLITUDE |Mommalized) oe + SMPTE pdermalzed) a= io =| aa aa - a = = = | a u | 4c = 12 1.0 Og 8 o4 ao. 5242500 > Adon! Ay hecte e288 aa . Men arate FAY ee TIME {rs} Figure 6. Coupler Inpur From Bus Cable - Waveform Template 100 .60 0 6-60 4 -E a 2006 ao 4 ao iw i320 TH inS} Figure 7, Coupler Ouipui To Reecies Stub - Wavefonn Template 1sSci 5242500 Ya cee er rem 172 ER oe a 1 [Ho ea + PS mm Pe ee eee Ae MD cept egy ees | Pho perc fre pa Gt See ee OE AB eee rer) | | Pon ode di i hae pean AA ee bo dite i SG view a Eijcre iy bres Gone 4 oe 7 rsenawes = =" 1 ae: | ( | -# af. ap a: a Zi ren | | + = an 4, | = asl re pce fae age cma. 1) = Fad ML akin Oey BOTTOM VIEW Figure 8. ARINC 629 Coupler Dimensions Tae el BE fee ieee ate saci ai i Ciara il HE oo case A fly a ? i 7 fo ae a Be eral Pos ~H 2 1? need Te Hid] or rapper. BT Ta VE Figure 9. Coupler Mounting Footprint 1855242500 For additional information contact: SCl SYSTEMS P.O. BOX 1000 M/S 240 Huntsville, Alabama 35807 Telephone: (256) 862-4569 FAX: (256) 882-4652 ad