# Copyright: Public domain. # Filename: TVCINITIALIZE.agc # Purpose: Part of the source code for Colossus 2A, AKA Comanche 055. # It is part of the source code for the Command Module's (CM) # Apollo Guidance Computer (AGC), for Apollo 11. # Assembler: yaYUL # Contact: Jim Lawton . # Website: www.ibiblio.org/apollo. # Pages: 936-944 # Mod history: 2009-05-11 JVL Adapted from the Colossus249/ file # of the same name, using Comanche055 page # images. # 2009-05-20 RSB Corrections: +80 -> +8D, added 4 missing # lines in TVCINIT1, changed the capitalization # of a couple of the "Page N" comments, # corrected a couple of lines in LOADCOEFF. # 2009-05-22 RSB In LOADCOEF, DXCH N10 +14D corrected to # TS N10 +14D. Also, various comment-marks # were added to comments following this # change. # # This source code has been transcribed or otherwise adapted from digitized # images of a hardcopy from the MIT Museum. The digitization was performed # by Paul Fjeld, and arranged for by Deborah Douglas of the Museum. Many # thanks to both. The images (with suitable reduction in storage size and # consequent reduction in image quality as well) are available online at # www.ibiblio.org/apollo. If for some reason you find that the images are # illegible, contact me at info@sandroid.org about getting access to the # (much) higher-quality images which Paul actually created. # # Notations on the hardcopy document read, in part: # # Assemble revision 055 of AGC program Comanche by NASA # 2021113-051. 10:28 APR. 1, 1969 # # This AGC program shall also be referred to as # Colossus 2A # Page 937 # NAME TVCDAPON (TVC DAP INITIALIZATION AND STARTUP CALL) # LOG SECTION...TVCINITIALIZE SUBROUTINE...DAPCSM # MODIFIED BY SCHLUNDT 21 OCTOBER 1968 # FUNCTIONAL DESCRIPTION # PERFORMS TVCDAP INITIALIZATION (GAINS, TIMING PARAMETERS, FILTER VARIABLES, ETC.) # COMPUTES STEERING (S40.8) GAIN KPRIMEDT, AND ZEROES PASTDELV,+1 VARIABLE # MAKES INITIALIZATION CALL TO "NEEDLER" FOR TVC DAP NEEDLES-SETUP # PERFORMS INITIALIZATION FOR ROLL DAP # CALLS TVCEXECUTIVE AT TVCEXEC, VIA WAITLIST # CALLS TVCDAP CDU-RATE INITIALIZATION PKG AT DAPINIT VIA T5 # PROVIDES FOR LOADING OF LOW-BANDWIDTH COEFFS AND GAINS AT SWICHOVR # CALLING SEQUENCE - T5LOC=2CADR(TVCDAPON,EBANK=BZERO), T5=.6SECT5 # IN PARTICULAR, CALLED BY "DOTVCON" IN P40 # MRCLEAN AND TVCINIT4 ARE POSSIBLE TVC-RESTART ENTRY POINTS # NORMAL EXIT MODE # TCF RESUME # SUBROUTINES CALLED # NEEDLER, MASSPROP # ALARM OR ABORT EXIT MODES # NONE # ERASABLE INITIALIZATION REQUIRED # CSMMASS, LEMMASS, DAPDATR1 (FOR MASSPROP SUBROUTINE) # TVC PAD LOADS (SEE EBANK6 IN ERASABLE ASSIGNMENTS) # PACTOFF, YACTOFF, CDUX # TVCPHASE AND THE T5 BITS OF FLAGWRD6 (SET AT DOTVCON IN P40) # OUTPUT # ALL TVC AND ROLL DAP ERASABLES, FLAGWRD6 (BITS 13,14), T5, WAITLIST # DEBRIS # NONE COUNT* $$/INIT BANK 17 SETLOC DAPS7 BANK EBANK= BZERO TVCDAPON LXCH BANKRUPT # T5 RUPT ARRIVAL (CALL BY DOTVCON - P40) EXTEND # SAVE Q REQUIRED IN RESTARTS (MRCLEAN AND QXCH QRUPT # TVCINIT4 ARE ENTRIES) MRCLEAN CAF NZERO # NUMBER TO ZERO, LESS ONE (MUST BE ODD) # TVC RESTARTS ENTER HERE (NEW BANK) +1 CCS A TS CNTR CAF ZERO TS L INDEX CNTR DXCH OMEGAYC # FIRST (LAST) TWO LOCATIONS CCS CNTR TCF MRCLEAN +1 # Page 938 EXTEND # SET UP ANOTHER T5 RUPT TO CONTINUE DCA INITLOC2 # INITIALIZATION AT TVCINIT1 DXCH T5LOC # THE PHSCHK2 ENTRY (REDOTVC) AT TVCDAPON CAF POSMAX # +3 IS IN ANOTHER BANK. MUST RESET TS TIME5 # BBCON TOO (FULL 2CADR), FOR THAT ENDMRC TCF RESUME # ENTRY. TVCINIT1 LXCH BANKRUPT EXTEND QXCH QRUPT TC IBNKCALL # UPDATE IXX, IAVG/TLX FOR DAP GAINS (R03 CADR MASSPROP # OR NOUNS 46 AND 47 MUST BE CORRECT) CAE EMDOT # SPS FLOW RATE, SCALED B+3 KG/CS EXTEND MP ONETHOU TS TENMDOT # 10-SEC MASS LOSS B+16 KG COM AD CSMMASS TS MASSTMP # DECREMENT FOR FIRST 10 SEC OF BURN CAE DAPDATR1 # CHECK LEM-ON/OFF MASK BIT14 CCS A CAF BIT1 # LEM-ON (BIT1) TS CNTR # LEM-OFF (ZERO) INDEX CNTR # LOAD THE FILTER COEFFICIENTS CAF CSMCFADR TS COEFFADR TC LOADCOEF INDEX CNTR # PICK UP LM-OFF,-ON KTLX/I CAE EKTLX/I # SCALED AT 1/(8 ASCREV) OF ACTUAL VALUE TS KTLX/I TCR S40.15 # COMPUTE 1/CONACC , VARK TVCINIT2 CS CNTR # PICK LM-OFF,-ON VALUE FOR FILTER PERIOD INDEX A # DETERMINATION: CAF BIT2 # BIT2 FOR CSM ONLY 40MS FILTER TS KPRIMEDT # BIT3 FOR CSM/LM 80MS FILTER COM # PREPARE T5TVCDT AD POSMAX AD BIT1 TS T5TVCDT CS BIT15 # RESET SWTOVER FLAG # Page 939 MASK FLAGWRD9 TS FLAGWRD9 INDEX CNTR # PICK UP LEM-OFF,-ON KPRIME CAE EKPRIME # SCALED (100 PI)/16 EXTEND MP KPRIMEDT # (TVCDT/2, SC.AT B+14CS) LXCH A # SC.AT PI/8 (DIMENSIONLESS) DXCH KPRIMEDT INDEX CNTR # PICK UP LEM-OFF,-ON REPFRAC CAE EREPFRAC TS REPFRAC INDEX CNTR # PICK UP ONE-SHOT CORRECTION TIME CAF TCORR TS CNTR CAF NEGONE # PREVENT STROKE TEST UNTIL CALLED TS STRKTIME CAF NINETEEN # SET VCNTR FOR VARIABLE-GAIN UPDATES IN TS VCNTR # 10 SECONDS (TVCEXEC 1/2 SEC RATE) TS V97VCNTR # FOR ENGFAIL (R41) LOGIC TVCINIT3 CAE PACTOFF # TRIM VALUES TO TRIM-TRACKERS, OUTPUT TS PDELOFF # TRACKERS, OFFSET-UPDATES, AND TS PCMD # OFFSET-TRACKER FILTERS TS DELPBAR # NOTE, LO-ORDER DELOFF,DELBAR ZEROED CAE YACTOFF TS YDELOFF TS YCMD TS DELYBAR ATTINIT CAE DAPDATR1 # ATTITUDE-ERROR INITIALIZATION LOGIC MASK BIT13 # TEST FOR CSM OR CSM/LM EXTEND BZF NEEDLEIN # BYPASS INITIALIZATION FOR CSM/LM CAF BIT1 # SET UP TEMPORARY COUNTER +5 TS TTMP1 INDEX TTMP1 CA ERRBTMP # ERRBTMP CONTAINS RCS ATTITUDE ERRORS EXTEND # ERRORY & ERRORZ (P40 AT DOTVCON) MP 1/ATTLIM # .007325(ERROR) = 0 IF ERROR < 1.5 DEG EXTEND BZF +8D # |ERROR| LESS THAN 1.5 DEG EXTEND # Page 940 BZMF +3 # |ERROR| > 1.5 DEG, AND NEG CA ATTLIM # |ERROR| > 1.5 DEG, AND POS TCF +2 +3 CS ATTLIM +2 INDEX TTMP1 TS ERRBTMP +8 CCS TTMP1 # TEST TEMPORARY COUNTER TCF ATTINIT +5 # BACK TO REPEAT FOR PITCH ERROR CA ERRBTMP # ERRORS ESTABLISHED AND LIMITED TS PERRB CA ERRBTMP +1 TS YERRB NEEDLEIN CS RCSFLAGS # SET BIT 3 FOR INITIALIZATION PASS AND GO MASK BIT3 # TO NEEDLER. WILL CLEAR FOR TVC DAP ADS RCSFLAGS # (RETURNS AFTER CADR) TC IBNKCALL CADR NEEDLER TVCINIT4 CAF ZERO # SET TVCPHASE TO INDICATE TVCDAPON-THRU- TS TVCPHASE # NEEDLEIN INITIALIZATION FINISHED. # (POSSIBLE TVC-RESTART ENTRY) CAE CDUX # PREPARE ROLL DAP TS OGANOW CAF BIT13 # IF ENGINE IS ALREADY OFF, ENGINOFF HAS EXTEND # ALREADY ESTABLISHED THE POST-BURN RAND DSALMOUT # CSMMASS (MASSBACK DOES IT). DONT EXTEND # TOUCH CSMMASS. IF ENGINE IS ON, BZF +3 # THEN ITS OK TO DO THE COPYCYCLE # EVEN BURNS LESS THAN 0.4 SEC ARE AOK CAE MASSTMP # COPYCYCLE TS CSMMASS +3 CAF .5SEC # CALL TVCEXECUTIVE (ROLLDAP CALL, ETC) TC WAITLIST EBANK= BZERO 2CADR TVCEXEC EXTEND # CALL FOR DAPINIT DCA DAPINIT5 DXCH T5LOC CAE T5TVCDT # (ALLOW TIME FOR RESTART COMPUTATIONS) TS TIME5 # Page 941 ENDTVCIN TCF RESUME PRESWTCH TCR SWICHOVR # ENTRY FROM V46 TC POSTJUMP # THIS PROVIDES AN EXIT FROM SWITCH-OVER CADR PINBRNCH # (PINBRNCH DOES A RELINT) SWICHOVR INHINT CA TVCPHASE # SAVE TVCPHASE TS PHASETMP CS BIT2 # SET TVCPHASE = -2 (INDICATES SWITCH-OVER TS TVCPHASE # TO RESTART LOGIC) +5 EXTEND # SAVE Q FOR RETURN (RESTART ENTRY POINT, QXCH RTRNLOC # TVCPHASE AND PHASETMP ALREADY SET) CAF NZEROJR # ZEROING LOOP FOR FILTER STORAGE LOCS +8 TS CNTRTMP MCLEANJR CA ZERO TS L INDEX CNTRTMP DXCH PTMP1 -1 CCS CNTRTMP CCS A TCF SWICHOVR +8D CS FLAGWRD9 # SET SWITCHOVER FLAG FOR DOWNLINK MASK BIT15 ADS FLAGWRD9 CAE EKTLX/I +2 # LOW BANDWIDTH GAINS - DAP TS KTLX/I TCR S40.15 +7 CAF FKPRIMDT # - STEERING TS KPRIMEDT CAF FREPFRAC # - TMC LOOP TS REPFRAC EXTEND # UPDATE TRIM ESTIMATES DCA DELPBAR DXCH PDELOFF EXTEND DCA DELYBAR DXCH YDELOFF CA LBCFADR # Page 942 TS COEFFADR TC LOADCOEF CAE PHASETMP # RESTORE TVCPHASE TS TVCPHASE TC RTRNLOC # BACK TO PRESWTCH OR TVCRESTARTS LOADCOEF EXTEND # LOAD DAP FILTER COEFFICIENTS INDEX COEFFADR # FROM: ERASABLE FOR CSM/LM HB DCA 0 # FIXED FOR CSM/LM LB DXCH N10 # FIXED FOR CSM EXTEND # NOTE: FOR CSM/LM, NORMAL COEFFICIENT INDEX COEFFADR # LOAD WILL BE HIGH BANDWIDTH PAD LOAD DCA 2 # ERASABLES. DURING CSM/LM SWITCHOVER, DXCH N10 +2 # THIS LOGIC IS USED TO LOAD LOW BANDWIDTH # COEFFICIENTS FROM FIXED MEMORY. EXTEND INDEX COEFFADR DCA 4 DXCH N10 +4 EXTEND INDEX COEFFADR DCA 6 DXCH N10 +6 EXTEND INDEX COEFFADR DCA 8D DXCH N10 +8D EXTEND INDEX COEFFADR DCA 10D DXCH N10 +10D EXTEND INDEX COEFFADR DCA 12D DXCH N10 +12D INDEX COEFFADR CA 14D TS N10 +14D TC Q # Page 943 S40.15 CAE IXX # GAIN COMPUTATIONS (1/CONACC, VARK) EXTEND # ENTERED FROM TVCINITIALIZE AND TVCEXEC MP 2PI/M # 2PI/M SCALED 1/(B+8 N M) DDOUBL # IXX SCALED B+20 KG-MSQ DDOUBL DDOUBL TS 1/CONACC # SCALED B+9 SEC-SQ/REV +7 CAE KTLX/I # ENTRY FROM CSM/LM V46 SWITCH-OVER EXTEND # SCALED (B+3 ASCREV) 1/SECSQ MP IAVG/TLX # SCALED B+2 SECSQ DDOUBL DDOUBL TS VARK # SCALED (B+3 ASCREV) TC Q CSMN10 DEC .99999 # N10 CSM ONLY FILTER COEFFICIENTS DEC -.2549 # N11/2 DEC .0588 # N12 DEC -.7620 # D11/2 DEC .7450 # D12 DEC .99999 # N20 DEC -.4852 # N21/2 DEC 0 # N22 DEC -.2692 # D22/2 DEC 0 # D22 LBN10 DEC +.99999 # N10 LOW BANDWIDTH FILTER COEFFICIENTS DEC -.3285 # N11/2 DEC -.3301 # N12 DEC -.9101 # D11/2 DEC +.8460 # D12 DEC +.03125 # N20 DEC 0 # N21/2 DEC 0 # N22 DEC -.9101 # D21/2 DEC +.8460 # D22 DEC +.5000 # N30 DEC -.47115 # N31/2 DEC +.4749 # N32 DEC -.9558 # D31/2 DEC +.9372 # D32 CSMCFADR GENADR CSMN10 # CSM ONLY COEFFICIENTS ADDRESS HBCFADR GENADR HBN10 # HIGH BANDWIDTH COEFFICIENTS ADDRESS # Page 944 LBCFADR GENADR LBN10 # LOW BANDWIDTH COEFFICIENTS ADDRESS NZERO DEC 51 # MUST BE ODD FOR MRCLEAN NZEROJR DEC 23 # MUST BE ODD FOR MCLEANJR ATTLIM DEC 0.00833 # INITIAL ATTITUDE ERROR LIMIT (1.5 DEG) 1/ATTLIM DEC 0.007325 # .007325(ERROR) = 0 IF ERROR < 1.5 DEG TCORR OCT 00005 # CSM +1 OCT 00000 # CSM/LM (HB,LB) FKPRIMDT DEC .0102 # CSM/LM (LB), (.05 X .08) SCALED AT PI/8 FREPFRAC DEC .0375 B-2 # CSM/LM (LB), 0.0375 SCALED AT B+2 NINETEEN = VD1 2PI/M DEC .00331017 B+8 # 2PI/M, SCALED AT 1/(B+8 N-M) ONETHOU DEC 1000 B-13 # KG/CS B3 TO KG/10SEC B16 CONVERSION EBANK= BZERO DAPINIT5 2CADR DAPINIT EBANK= BZERO INITLOC2 2CADR TVCINIT1