DAPIDLER_PROGRAM.agc
### FILE="Main.annotation"
## Copyright: Public domain.
## Filename: DAPIDLER_PROGRAM.agc
## Purpose: A section of Luminary 1C, revision 131.
## It is part of the source code for the Lunar Module's (LM)
## Apollo Guidance Computer (AGC) for Apollo 13.
## This file is intended to be a faithful transcription, except
## that the code format has been changed to conform to the
## requirements of the yaYUL assembler rather than the
## original YUL assembler.
## Reference: pp. 1402-1412
## Contact: Ron Burkey <info@sandroid.org>.
## Website: www.ibiblio.org/apollo/index.html
## Mod history: 06/07/03 RSB. Began transcribing.
## 05/14/05 RSB Corrected website reference above.
## 2017-01-06 RSB Page numbers now agree with those on the
## original hardcopy, as opposed to the PDF page
## numbers in 1701.pdf.
## 2017-01-28 RSB Comment-text fixes identified for Luminary 69.
## 2017-02-28 RSB Proofed comment text using octopus/ProoferComments.
## 2017-03-10 RSB Comment-text fixes noted in proofing Luminary 116.
## Page 1402
# THE DAPIDLER PROGRAM IS STARTED BY FRESH START AND RESTART. THE DAPIDLER PROGRAM IS DONE 10 TIMES
# PER SECOND UNTIL THE ASTRONAUT DESIRES THE DAP TO WAKE UP, AND THE IMU AND CDUS ARE READY FOR USE BY THE DAP.
# THE NECESSARY INITIALIZATION OF THE DAP IS DONE BY THE DAPIDLER PROGRAM.
BANK 16
SETLOC DAPS1
BANK
EBANK= AOSQ
COUNT* $$/DAPID
CHEKBITS EXTEND
READ CHAN31 # IF BOTH BIT13 AND BIT14 ARE ONE, THEN
COM # THE MODE SELECT SWITCH IS IN THE OFF
MASK BIT13-14 # POSITION, AND SO THE DAP SHOULD BE OFF,
EXTEND # WITH NO ATTITUDE ERROR DISPLAY.
BZF MOREIDLE
CS IMODES33
MASK BIT6
CCS A
TCF JUMPDSP
CS RCSFLAGS # IMU NOT USABLE. SET UP INITIALIZATION
MASK BIT3 # FLAG FOR ATT ERROR DISPLAY ROUTINE.
ADS RCSFLAGS
TCF SHUTDOWN
CHEKMORE CAF BIT10 # BIT 10 OF 30 IS PGNCS CONTROL OF S/C
EXTEND
RAND CHAN30 # BITS IN 30 ARE INVERTED
CCS A
TCF MOREIDLE
RETURN
## Page 1403
# DAPIDLER ENTRY.
DAPIDLER LXCH BANKRUPT # INTERRUPT LEAD INS (CONTINUED)
EXTEND
QXCH QRUPT
CA RCSFLAGS
MASK BIT13
CCS A # CHECK IF 1/ACCJOB HAS BEEN SET UP SINCE
TCF CHECKUP # THE LAST FRESH START OR RESTART.
CA BIT13
ADS RCSFLAGS # BIT 13 IS 1.
CAF PRIO27
TC NOVAC # SET UP JOB TO DO A LITTLE INITIALIZATION
EBANK= AOSQ # AND EXECUTE 1/ACCS.
2CADR 1/ACCSET # (WILL BRANCH TO MOREIDLE ON ACCSOKAY)
CHECKUP TC CHEKBITS # CHECK TO SEE IF LM DAP IS TO GO ON AND
# DO ERROR DISPLAY.
CAE DAPBOOLS # IF 1/ACCS HAS NOT BEEN COMPLETED, IDLE.
MASK ACCSOKAY # NOTE: ONLY FRESH START AND RESTART
EXTEND # KNOCK THIS BIT DOWN.
BZF MOREIDLE
STARTDAP TC IBNKCALL # ZERO ATTITUDE ERROR AND DESIRED RATES.
FCADR ZATTEROR
CAF ZERO # ********** INITIALIZE: **********
TS TJP
TS TJU
TS TJV
TS OMEGAP # RATES IN BODY (PILOT) COORDINATES.
TS OMEGAQ
TS OMEGAR
TS TRAPEDP
TS TRAPEDQ
TS TRAPEDR
TS AOSQ # OFFSET ACCELERATION ESTIMATES.
TS AOSQ +1
TS AOSR
TS AOSR +1
TS ALPHAQ # COPIES OF OFFSET ESTIMATES FOR DOWNLIST.
TS ALPHAR
TS NEGUQ
TS NEGUR
TS AOSQTERM # QRAXIS RATE DERIVATION TERMS AND KALMAN
TS AOSRTERM # FILTER INITIALIZATION TERMS.
TS QACCDOT # DESCENT ACCELERATION DERIVATIVE EST.
TS RACCDOT
## Page 1404
TS ALLOWGTS # AOSTASK FLAG FOR QRAXIS RCS CONTROL USE.
TS COTROLER # DO TRYGTS ON FIRST PASS (WILL GO TO RCS)
TS INGTS # RECOGNIZE FIRST GTS PASS AS SUCH.
TS QGIMTIMR # STOP GIMBAL DRIVES. (PROBABLY WOULD BE
TS RGIMTIMR # GOOD ENOUGH JUST TO INACTIVATE TIMERS)
TS OLDPMIN # MINIMUM IMPULSE MODE ERASABLES
TS OLDQRMIN
TS PJETCTR # INITIALIZE DOCKED JET INHIBITION
TS UJETCTR # COUNTERS
TS VJETCTR
CALLGMBL EQUALS BIT5 # RCSFLAGS INITIALIZATION.
CS MANFLAG
MASK RCSFLAGS # NEGUQ(R) HAVE BEEN GENERATED.
TS RCSFLAGS
# SET UP "OLD" MEASURED CDU ANGLES:
EXTEND
DCA CDUX # OLDXFORP AND OLDYFORP
DXCH OLDXFORP
CA CDUZ
TS OLDZFORQ
CS RCSFLAGS
MASK BIT12
ADS RCSFLAGS # BIT 12 SET TO 1.
CA FOUR
TS SKIPU
TS SKIPV
CA POSMAX
TS TIME6
TS T6NEXT
TS T6FURTHA
CA ZERO
TS T6NEXT +1
TS T6FURTHA +1
TS NXT6ADR
TS NEXTP
TS NEXTU
TS NEXTV
CS TEN
TS DAPZRUPT # JASK NOT IN PROGRESS, INITIALIZE NEG.
CA TWO
TS NPTRAPS
TS NQTRAPS
TS NRTRAPS
EXTEND
DCA PAXADIDL
DXCH T5ADR
SETTIME5 CAF MS100
TS TIME5
## Page 1405
TCF RESUME
EBANK= AOSQ
IDLERADR 2CADR DAPIDLER
MOREIDLE TC IBNKCALL # CALCULATE Q,R-AXES ATTITUDE ERRORS.
CADR QERRCALC
TC IBNKCALL
CADR CALCPERR # CALCULATE P AXIS ATTITUDE ERRORS.
SHUTDOWN EXTEND
DCA IDLERADR
DXCH T5ADR
CAF ZERO # KILL ANY POSSIBLE JET REQUESTS
TS NEXTP
TS NEXTU
TS NEXTV
EXTEND # COMMAND JETS OFF.
WRITE CHAN5
EXTEND
WRITE CHAN6
CS BGIM23 # TURN TRIM GIMBAL OFF
EXTEND
WAND CHAN12
TCF SETTIME5 # RETURN IN 100 MSEC.
MANFLAG OCT 03021
BGIM23 OCTAL 07400
EBANK= OMEGAP
PAXADIDL 2CADR PAXIS
MS100 = OCT37766
COSMG = ITEMP1
JUMPDSP EXTEND # TRANSFER TO BANK 20
DCA DSPCADR # FOR ATTITUDE ERROR DISPLAYS
DTCB
EBANK= AK
DSPCADR 2CADR ALTDSPLY
## Page 1406
BANK 20
SETLOC DAPS3
BANK
COUNT* $$/NEEDL
# PROGRAM: ALTDSPLY
# MOD 0. 6 DEC 1967
# AUTHOR: CRAIG WORK, DON KEENE, MIT IL
# MOD 3 BY DON KEENE AUG 1, 1968 MOVED PROGRAM TO BANK 20
#
# PROGRAM DESCRIPTION:
# ALTDSPLY REVERSES THE DSPLYALT BIT OF RCSFLAGS EACH TIME IT IS CALLED, WHICH IS PRESUMABLY EVERY 100 MS.
# IF THE REVERSED BIT IS ONE, NEEDLER IS CALLED TO DISPLAY ATTITUDE ERRORS. IF THE BIT IS ZERO, THE ATTITUDE ERR-
# ORS ARE CALCULATED AS 1) ESTIMATED RATES (FOLLOWING) IF NEED2FLG = 1, OTHERWISE AS 2) DAP FOLLOWING ERRORS FOR
# NEEDLFLG = 0 AND 3) TOTAL ATTITUDE ERRORS FOR NEEDLFLG = 1.
#
# WARNING: ALTDSPLY MAY ONLY BE CALLED WITH INTERRUPT INHIBITED.
#
# WARNING: EBANK MUST BE SET TO 6 WHEN USING THIS ROUTINE.
#
# INPUT: RCSFLAGS AND 1) IF NEEDLFLG = 0, INPUT PERROR, QERROR, RERROR.
# 2) IF NEEDLFLG = 1, INPUT CPHI,CTHETA,CPSI,CDUX,CDUY,CDUZ,M11,M21,M32,M22,M32. (GPMATRIX)
# 3) IF NEED2FLG = 1, INPUT OMEGAP, OMEGAQ, AND OMEGAR.
#
# OUTPUTS: RCSFLAGS WITH DSPLYALT REVERSED, AK, AK1, AK2, + NEEDLER OUTPUTS.
#
# ENTRY: TCF ALTDSPLY
#
# EXIT: TCF CHEKMORE
#
# ALARM OR ABORT EXITS: NONE
#
# SUBPROGRAMS CALLED: NEEDLER, OVERSUB2
#
# DEBRIS: A, L, AND NEEDLER DEBRIS.
ALTDSPLY CA RCSFLAGS # INVERT THE DISPLAY ALTERNATION BIT.
TS L
CA DSPLYALT
EXTEND
RXOR LCHAN
TS RCSFLAGS
MASK DSPLYALT
CCS A # IS ALTERNATION FLAG ZERO?
## Page 1407
TCF NEEDLER
CS FLAGWRD0 # CHECK FOR RATE DISPLAY TO ERROR NEEDLES
MASK NEED2BIT # VIA EXTENDED VERB 60
EXTEND
BZF DISPRATE
CAE FLAGWRD0 # NEEDLFLG WILL INDICATE TOTAL OR DAP AT-
MASK NEEDLBIT # TITUDE ERROR DISPLAY REQUEST.
CCS A
TCF DSPLYTOT # TOTAL ERROR IS NEEDED IN AK, AK +1, AK +2
CS QERROR # YES. DISPLAY ATT ERRORS ON THE ,-BALL.
TS AK +1 # ERROR COMPLEMENTS ARE INPUT TO NEEDLER.
CS RERROR
TS AK +2
CS PERROR
XCH AK
TCF RETNMORE # DISPLAY THESE THE NEXT TIME THROUGH
DISPRATE CS OMEGAQ # LOAD ESTIMATED RATES (FOLLOWING)
TS AK +1
CS OMEGAR
TS AK +2
CS OMEGAP
XCH AK
TCF RETNMORE
# CALCULATE GIMBAL ANGLE TOTAL ERRORS, RESOLVE INTO PILOT AXES, STORE TOTAL ERRORS FOR NEEDLER. Q-AXIS FIRST.
DSPLYTOT EXTEND
QXCH ITEMP1 # SAVE Q FOR CHEKBITS RETURN.
CA CTHETA # DESIRED ATTITUDE, Y-AXIS, 2'S COMP.
EXTEND # SUBTRACT CURRENT ATTITUDE.
MSU CDUY # DIFFERENCE SCALED AT PI, 1'S COMP.
TS AK # SAVE FOR R-ERROR CALCULATION.
EXTEND
MP M21 # (CHTETA-CDUY)*M21 SCALED AT PI RADIANS.
XCH AK +1 # STORE FIRST TERM OF Q ERROR.
CA CPSI # DESIRED ATTITUDE, Z-AXIS, 2'S COMP.
EXTEND # SUBTRACT CURRENT ATTITUDE.
MSU CDUZ # DIFFERENCE SCALED AT PI, 1'S COMP.
TS AK +2 # SAVE Z-AXIS TERM FOR R ERROR CALCULATION
EXTEND
MP M22 # (CPSI-CDUZ)*M22, SCALED AT PI RADIANS.
AD AK +1 # Q ERROR COMPLETE , AT PI RAD.
TC OVERSUB2 # PIN NEEDLES IN CASE OF OVERFLOW.
TS AK +1
## Page 1408
# R ERROR CALCULATION NEXT.
CA AK # Y-AXIS DIFFERENCE STORED BY Q-AXIS CALC.
EXTEND
MP M31 # (CTHETA-CDUY)*M31, SCALED AT PI RADIANS.
XCH AK +2 # FIRST TERM OF R ERROR.
# Z-AXIS DIFFERENCE, STORED BY A CALC. IS
EXTEND # RECOVERED BY THE EXCHANGE.
MP M32 # (CPSI-CDUZ)*M32, SCALED AT PI RADIANS.
AD AK +2 # R ERROR COMPLETE , AT PI RAD.
TC OVERSUB2 # PIN NEEDLES IN CASE OF OVERFLOW.
TS AK +2
# NOW CALCULATE P ERROR. (NOTE THAT M13 = 1, SCALED AT 1, SO THE MULTIPLICATION IS BY-PASSED.)
CA AK # Y-AXIS DIFFERENCE STORED BY Q AXIS CALC.
EXTEND
MP M11 # (CTHETA-CDUY)*M11 SCALED AT PI RADIANS.
XCH AK # FIRST TERM OF P ERROR IN AK, AT PI RAD.
CAE CPHI # DESIRED ATTITUDE, X-AXIS, 2'S COMP.
EXTEND # SUBTRACT CURRENT X ATTITUDE.
MSU CDUX # X-AXIS DIFFERENCE, 1'S COMP, AT PI RAD.
# M13 = 1, SO BYPASS THE MULTIPLICATION.
# EXTEND
# MP M13 (CPHI-CDUX)*M13 SCALED AT PI RADIANS.
AD AK # P ERROR COMPLETE , SCALED AT PI RAD
TC OVERSUB2 # PIN NEEDLES IN CASE OF OVERFLOW.
TS AK
EXTEND
QXCH ITEMP1 # RESTORE Q FOR CHEKBITS RETURN.
TCF RETNMORE # DISPLAY THESE THE NEXT TIME THROUGH
## Page 1409
# FDAI ATTITUDE ERROR DISPLAY SUBROUTINE
#
# PROGRAM DESCRIPTION: D. KEENE 5/24/67
# MOD 1 BY CRAIG WORK, 12 DEC 67
# MOD 2 BY CRAIG WORK, 6 APRIL 68 CONVERTS ATTITUDE ERROR DISPLAY SCALING FROM 16 7/8 DEG. TO 42 3/16 DEGREES.
#
# THIS SUBROUTINE IS USED TO DISPLAY ATTITUDE ERRORS ON THE FDAI VIA THE DIGITAL TO ANALOG CONVERTERS (DACS)
# IN THE CDUS. CARE IS TAKEN TO METER OUT THE APPROPRIATE NUMBER OF PULSES TO THE IMU ERROR COUNTERS AND PREVENT
# OVERFLOW, TO CONTROL THE RELAY SEQUENCING, AND TO AVOID INTERFERENCE WITH THE COARSE ALIGN LOOP WHICH ALSO USES
# THE DACS.
#
# CALLING SEQUENCE:
# DURING THE INITIALIZATION SECTION OF THE USER'S PROGRAM, BIT3 OF RCSFLAGS SHOULD BE SET TO INITIATE THE
# TURN-ON SEQUENCE WITHIN THE NEEDLES PROGRAM:
# CS RCSFLAGS IN EBANK6
# MASK BIT3
# ADS RCSFLAGS
# THEREAFTER, THE ATTITUDE ERRORS GENERATED BY THE USER SHOULD BE TRANSFERED TO THE FOLLOWING LOCATIONS IN EBANK6:
# AK SCALED 180 DEGREES NOTE: THESE LOCATIONS ARE SUBJECT
# AK1 SCALED 180 DEGREES TO CHANGE
# AK2 SCALED 180 DEGREES
# FULL SCALED DEFLECTION OF THE NEEDLES CORRESPONDS TO 5 1/16 DEGREES, WHILE 384 BITS IN THE IMU ERROR COUNTER
# CORRESPONDS TO 42 3/16 DEGREES. (DAC MAXIMUM CAPACITY IS 384 BITS.) 46 BITS EFFECTIVELY PIN THE NEEDLES.
# FOR RATE DISPLAY, FULL SCALE NEEDLE DEFLECTION IS 1 17/64 DEG/SEC, AND A FULL COUNTER IS ABOUT 10.5 DEG/SEC.
# A CALL TO NEEDLER WILL THEN UPDATE THE DISPLAY:
# INHINT
# TC IBNKCALL NOTE: EBANK SHOULD BE SET TO E6
# CADR NEEDLER
# RELINT
# THIS PROCESS SHOULD BE REPEATED EACH TIME THE ERRORS ARE UPDATED. AT LEAST 3 PASSES THRU THE PROGRAM ARE
# REQUIRED BEFORE ANYTHING IS ACTUALLY DISPLAYED ON THE ERROR METERS.
# NOTE: EACH CALL TO NEEDLER MUST BE SEPARATED BY AT LEAST 50 MS TO ASSURE PROPER RELAY SEQUENCING.
#
# ERASABLE USED:
# AK CDUXCMD
# AK1 CDUYCMD
# AK2 CDUZCMD
# EDRIVEX A,L,Q
# EDRIVEY T5TEMP
## Page 1410
# EDRIVEZ DINDX
#
# SWITCHES: RCSFLAGS BITS 3,2
#
# I/O CHANNELS: CHAN12 BIT 4 (COARSE ALIGN - READ ONLY)
# CHAN12 BIT 6 (IMU ERROR COUNTER ENABLE)
# CHAN14 BIT 13,14,15 (DAC ACTIVITY)
#
# SIGN CONVENTION< AK = THETAC - THETA
# WHERE THETAC = COMMAND ANGLE
# THETA = PRESENT ANGLE
NEEDLER CA RCSFLAGS
MASK SIX
EXTEND
BZF NEEDLES3
MASK BIT3
EXTEND
BZF NEEDLER2 # BIT3 = 0, BIT2 = 1
CS BIT6 # FIRST PASS BIT3 = 1
EXTEND # DISABLE IMU ERROR COUNTER TO ZERO DACS
WAND CHAN12 # MUST WAIT AT LEAST 60 MS BEFORE
NEEDLE11 CS ZERO # ENABLING COUNTERS.
TS AK # ZERO THE INPUTS ON FIRST PASS
TS AK1
TS AK2
TS EDRIVEX # ZERO THE DISPLAY REGISTERS
TS EDRIVEY
TS EDRIVEZ
TS CDUXCMD # ZERO THE OUT COUNTERS
TS CDUYCMD
TS CDUZCMD
CS SIX # RESET RCSFLAGS FOR PASS2
MASK RCSFLAGS
AD BIT2
TS RCSFLAGS
TCF RETNMORE
NEEDLER2 CAF BIT6 # ENABLE IMU ERROR COUNTERS
EXTEND
WOR CHAN12
CS SIX # RESET RCSFLAGS TO DISPLAY ATTITUDE
MASK RCSFLAGS # ERRORS WAIT AT LEAST 4 MS FOR
TS RCSFLAGS # RELAY CLOSURE
TCF RETNMORE
NEEDLES3 CAF BIT6 # CHECK TO SEE IF IMU ERROR COUNTER
## Page 1411
EXTEND # IS ENABLED
RAND CHAN12
CCS A # IF NOT, RE-INITIALIZE NEEDLER.
TCF NEEDLES
CS RCSFLAGS # SET UP INITIALIZATION FLAG IN RCSFLAGS.
MASK BIT3
ADS RCSFLAGS
TCF RETNMORE
NEEDLES CAF TWO
DACLOOP TS DINDX
CS ONETENTH # RESCALE INPUTS TO + OR - 1800 DEGREES.
EXTEND
INDEX DINDX
MP AK
TS L
CCS A
CA DACLIMIT
TCF +2
CS DACLIMIT
AD L
TS T5TEMP # OVFLO CHK
TCF +4
INDEX A # ON OVERFLOW LIMIT OUTPUT TO +-384
CAF DACLIMIT
TS L
INDEX DINDX
CS EDRIVEX # CURRENT VALUE OF DAC
AD L
INDEX DINDX
ADS CDUXCMD
INDEX DINDX
LXCH EDRIVEX
CCS DINDX
TCF DACLOOP
CAF 13,14,15
EXTEND
WOR CHAN14 # SET DAC ACTIVITY BITS
TCF RETNMORE
DEC -384
DACLIMIT DEC 16000
DEC 384
ONETENTH OCT 03146 # DECIMAL +0.1, SCALED AT 1.
DSPLYALT EQUALS BIT4 # 100 MS ALTERNATION BIT IN RCSFLAGS
OVERSUB2 TS 7 # RETURNS A UNCHANGED OR LIMITED TO
## Page 1412
TC Q # POSMAX OR NEGMAX IF A HAS OVERFLOW
INDEX A
CS LIMITS # DUPLICATE CODING IN BANK 16
TC Q
RETNMORE EXTEND # RETURN TO CHEKMORE
DCA MORECADR
DTCB
EBANK= AOSQ
MORECADR 2CADR CHEKMORE
