Source Code
007657,000001: # Copyright: Public domain.
007658,000002: # Filename: RCS_FAILURE_MONITOR.agc
007659,000003: # Purpose: RCS FAILURE MONITOR code for for Luminary 1C, revision 131.
007660,000004: # It is part of the source code for the Lunar Module's (LM)
007661,000005: # Apollo Guidance Computer (AGC) for Apollo 13 and Apollo 14.
007662,000006: # This file is intended to be a faithful transcription, except
007663,000007: # that the code format has been changed to conform to the
007664,000008: # requirements of the yaYUL assembler rather than the
007665,000009: # original YUL assembler.
007666,000010: # Reference: pp. 197-199 of 1729.pdf.
007667,000011: # Contact: Ron Burkey <info@sandroid.org>.
007668,000012: # Website: www.ibiblio.org/apollo/index.html
007669,000013: # Mod history: 05/05/03 RSB. Began transcribing.
007670,000014: # 05/14/05 RSB Corrected website references above.
007671,000015:
007672,000016: # Page 197
007673,000017: # PROGRAM DESCRIPTION:
007674,000018:
007675,000019: # AUTHOR: J. S. MILLER
007676,000020:
007677,000021: # MODIFIED 6 MARCH 1968 BY P. S. WEISSMAN TO SET UP JOB FOR 1/ACCS WHEN THE MASKS ARE CHANGED.
007678,000022:
007679,000023: # THIS ROUTINE IS ATTACHED TO T4RUPT, AND IS ENTERED EVERY 480 MS. ITS FUNCTION IS TO EXAMINE THE LOW 8 BITS
007680,000024: # OF CHANNEL 32 TO SEE IF ANY ISOLATION-VALVE CLOSURE BITS HAVE APPEARED OR DISAPPEARED (THE CREW IS WARNED OF JET
007681,000025: # FAILURES BY LAMPS LIT BY THE GRUMMAN FAILURE-DETECTION CIRCUITRY; THEY MAY RESPOND BY OPERATING SWITCHES WHICH
007682,000026: # ISOLATE PARIS OF JETS FROM THE PROPELLANT TANKS AND SET BITS IN CHANNEL 32). iN THE EVENT THAT CHANNEL 32 BITS
007683,000027: # DIFFER FROM `PVALVEST', THE RECORD OF ACTIONS TAKEN BY THIS ROUTINE, THE APPROPRIATE BITS IN `CH5MASK' &
007684,000028: # `CH6MASK', USED BY THE DAP JET-SELECTION LOGIC, ARE UPDATED, AS IS `PVALVEST'. TO SPEED UP & SHORTEN THE
007685,000029: # ROUTINE, NO MORE THAN ONE CHANGE IS ACCEPTED PER ENTRY. THE HIGHEST-NUMBERED BIT IN CHANNEL 32 WHICH REQUIRES
007686,000030: # ACTION IS THE ONE PROCESSED.
007687,000031:
007688,000032: # THE CODING IN THE FAILURE MONITOR HAS BEEN WRITTEN SO AS TO HAVE ALMOST COMPLETE RESTART PROTECTION. FOR
007689,000033: # EXAMPLE, NO ASSUMPTION IS MADE WHEN SETTING A `CH5MASK' BIT TO 1 THAT THE PREVIOUS STATE IS 0, ALTHOUGH IT OF
007690,000034: # COURSE SHOULD BE. ONE CASE WHICH MAY BE SEEN TO EVADE PROTECTION IS THE OCCURRENCE OF A RESTART AFTER UPDATING
007691,000035: # ONE OR BOTH DAP MASK-WORDS BUT BEFORE UPDATING `PVALVEST', COUPLED WITH A CHANGE IN TEH VALVE-BIT BACK TO ITS
007692,000036: # FORMER STATE. THE CONSEQUENCE OF THIS IS THAT THE NEXT ENTRY WOULD NOT SEE THE CHANGE INCOMPLETELY INCORP-
007693,000037: # ORATED BY THE LAST PASS (BECAUSE IT WENT AWAY AT JUST THE RIGHT TIME), BUT THE DAP MASK-WORDS WILL BE INCORRECT.
007694,000038: # THIS COMBINATION OF EVENTS SEEMS QUITE REMOTE, BUT NOT IMPOSSIBLE UNLESS THE CREW OPERATES THE SWITCHES AT HALF-
007695,000039: # SECOND INTERVALS OR LONGER. IN ANY EVENT, A DISAGREEMENT BETWEEN REALITY AND THE DAP MASKS WILL BE CUREED IF
007696,000040: # THE MISINTERPRETED SWITCH IS REVERSED AND THEN RESTORED TO ITS CORRECT POSITION (SLOWLY).
007697,000041:
007698,000042: # CALLING SEQUENCE:
007699,000043:
007700,000044: # TCF RCSMONIT # (IN INTERRUPT MODE, EVERY 480 MS.)
007701,000045:
007702,000046: # EXIT: TCF RCSMONEX (ALL PATHS EXIT VIA SUCH AN INSTRUCTION)
007703,000047:
007704,000048: 06,3164 5270 RCSMONEX EQUALS RESUME
007705,000049:
007706,000050: # ERASABLE INITIALIZATION REQUIRED:
007707,000051:
007708,000052: # VIA FRESH START: PVALVEST = +0 (ALL JETS ENABLED)
007709,000053: # CH5MASK,CH6MASK = +0 (ALL JETS OK)
007710,000054:
007711,000055: # OUTPUT: CH5MASK 7 CH6MASK UPDATED (1'S WHERE JETS NOT TO BE USED, IN CHANNEL 5 & 6 FORMAT)
007712,000056: # PVALTEST UPDATED (1'S WHEN VALVE CLOSURES HAVE BEEN TRANSLATED INTO CH5MASK & CH6MASK; CHAN 32 FORMAT)
007713,000057: # JOB TO DO 1/ACCS.
007714,000058:
007715,000059: # DEBRIS: A, L, AND Q AND DEBRIS OF NOVAC.
007716,000060:
007717,000061: # SUBROUTINE CALLED: NOVAC.
007718,000062:
007719,000063: 06,3164 1257 EBANK= CH5MASK
007720,000064:
007721,000065: 23,2000 BANK 23
007722,000066: 06,2000 SETLOC RCSMONT
007723,000067: 06,2000 BANK
007724,000068: # Page 198
007725,000069: 06,3164 COUNT* $$/T4RCS
007726,000070:
007727,000071: 06,3164 44755 RCSMONIT CS ZERO
007728,000072: 06,3165 00006 EXTEND
007729,000073: 06,3166 06032 RXOR CHAN32 # PICK UP + INVERT INVERTED CHANNEL 32.
007730,000074: 06,3167 74357 MASK LOW8 # KEEP JET-FAIL BITS ONLY.
007731,000075: 06,3170 54002 TS Q
007732,000076:
007733,000077: 06,3171 41273 CS PVALVEST
007734,000078: 06,3172 70002 MASK Q # FORM PC + PC.
007735,000079: 06,3173 54001 TS L # (P = PREVIOUS ISOLATION VALVE STATE,
007736,000080: 06,3174 40002 CS Q # C = CURRENT VALVE STATE (CH32)).
007737,000081: 06,3175 71273 MASK PVALVEST
007738,000082: 06,3176 26001 ADS L # RESULT NZ INDICATES ACTION REQUIRED.
007739,000083:
007740,000084: 06,3177 00006 EXTEND
007741,000085: 06,3200 15270 BZF RCSMONEX # QUIT IF NO ACTION REQUIRED.
007742,000086:
007743,000087: 06,3201 00006 EXTEND
007744,000088: 06,3202 74745 MP BIT7 # MOVE BITS 8-1 OF A TO 14-7 OF L.
007745,000089: 06,3203 56001 XCH L # XERO TO L IN THE PROCESS.
007746,000090:
007747,000091: 06,3204 24001 -3 INCR L
007748,000092: 06,3205 60000 DOUBLE # BOUND TO GET OVERFLOW IN THIS LOOP,
007749,000093: 06,3206 54000 OVSK # SINCE WE ASSURED INITIAL NZ IN A.
007750,000094: 06,3207 13204 TCF -3
007751,000095:
007752,000096: 06,3210 50001 INDEX L
007753,000097: 06,3211 34743 CA BIT8 -1 # SAVE THE RELEVANT BIT (8-1).
007754,000098: 06,3212 54002 TS Q
007755,000099: 06,3213 71273 MASK PVALVEST # LOOK AT PREVIOUS VALVE STATE BIT.
007756,000100: 06,3214 10000 CCS A
007757,000101: 06,3215 13231 TCF VOPENED # THE VALVE HAS JUST BEEN OPENED.
007758,000102:
007759,000103: 06,3216 41257 CS CH5MASK # THE VALVE HAS JUST BEEN CLOSED.
007760,000104: 06,3217 50001 INDEX L
007761,000105: 06,3220 73250 MASK 5FAILTAB
007762,000106: 06,3221 27257 ADS CH5MASK # SET INHIBIT BIT FOR CHANNEL 5 JET.
007763,000107:
007764,000108: 06,3222 41260 CS CH6MASK
007765,000109: 06,3223 50001 INDEX L
007766,000110: 06,3224 73260 MASK 6FAILTAB
007767,000111: 06,3225 27260 ADS CH6MASK # SET INGIBIT BIT FOR CHANNEL 6 JET
007768,000112:
007769,000113: 06,3226 30002 CA Q
007770,000114: 06,3227 27273 ADS PVALVEST # RECORD ACTION TAKEN.
007771,000115:
007772,000116: 06,3230 13244 TCF 1/ACCFIX # SET UP 1/ACCJOB AND EXIT.
007773,000117:
007774,000118: # Page 199
007775,000119: 06,3231 50001 VOPENED INDEX L # A VALVE HAS JUST BEEN OPENED.
007776,000120: 06,3232 43250 CS 5FAILTAB
007777,000121: 06,3233 71257 MASK CH5MASK
007778,000122: 06,3234 55257 TS CH5MASK # REMOVE INHIBIT BIT FOR CHANNEL 5 JET.
007779,000123:
007780,000124: 06,3235 50001 INDEX L
007781,000125: 06,3236 43260 CS 6FAILTAB
007782,000126: 06,3237 71260 MASK CH6MASK
007783,000127: 06,3240 55260 TS CH6MASK # REMOVE INHIBIT BIT FOR CHANNEL 6 JET.
007784,000128:
007785,000129: 06,3241 40002 CS Q
007786,000130: 06,3242 71273 MASK PVALVEST
007787,000131: 06,3243 55273 TS PVALVEST # RECORD ACTION TAKEN.
007788,000132:
007789,000133: 06,3244 37720 1/ACCFIX CAF PRIO27 # SET UP 1/ACCS SO THAT THE SWITCH CURVES
007790,000134: 06,3245 05072 TC NOVAC # FOR TJETLAW CAN BE MODIFIED IF CH5MASK
007791,000135: 06,3246 E6,1536 EBANK= AOSQ # HAS BEEN ALTERED.
007792,000136: 06,3246 03652 42106 2CADR 1/ACCJOB
007793,000137:
007794,000138: 06,3250 15270 TCF RCSMONEX # EXIT.
007795,000139:
007796,000140: 06,3251 5FAILTAB EQUALS -1 # CH 5 JET BIT CORRESPONDING TO CH 32 BIT:
007797,000141: 06,3251 00040 OCT 00040 # 8
007798,000142: 06,3252 00020 OCT 00020 # 7
007799,000143: 06,3253 00100 OCT 00100 # 6
007800,000144: 06,3254 00200 OCT 00200 # 5
007801,000145: 06,3255 00010 OCT 00010 # 4
007802,000146: 06,3256 00001 OCT 00001 # 3
007803,000147: 06,3257 00004 OCT 00004 # 2
007804,000148: 06,3260 00002 OCT 00002 # 1
007805,000149:
007806,000150: 06,3261 6FAILTAB EQUALS -1 # CH 6 JET BIT CORRESPONDING TO CH 32 BIT:
007807,000151: 06,3261 00010 OCT 00010 # 8
007808,000152: 06,3262 00020 OCT 00020 # 7
007809,000153: 06,3263 00004 OCT 00004 # 6
007810,000154: 06,3264 00200 OCT 00200 # 5
007811,000155: 06,3265 00001 OCT 00001 # 4
007812,000156: 06,3266 00002 OCT 00002 # 3
007813,000157: 06,3267 00040 OCT 00040 # 2
007814,000158: 06,3270 00100 OCT 00100 # 1
007815,000159:
007816,000160:
End of include-file RCS_FAILURE_MONITOR.agc. Parent file is MAIN.agc