Source Code

These source-code files were from the printout at the MIT Museum, with many thanks to Deborah Douglas, the Museum's Curator of Science and Technology, for releasing it to us. The printout was digitally photographed by Paul Fjeld. A team of volunteers transcribed the source code manually from these images or, where appropriate, modified already-transcribed but similar source Luminary 131 (Apollo 13) source code to agree with the images from the printout. Note that the page images presented online are of reduced quality, and that higher-quality images are available. Report any conversion errors or legibility problems in page images to info@sandroid.org. Notations on the program listing read, in part:

	GAP:  ASSEMBLE REVISION 001 OF AGC PROGRAM LMY99 BY NASA 2021112-061
	20'35 OCT. 28,1968
Note that the date is the date of the printout, not the date of the program revision.

002064,000002:                                                                                                  ## Copyright:   Public domain.
002065,000003:                                                                                                  ## Filename:    INPUT_OUTPUT_CHANNEL_BIT_DESCRIPTIONS.agc
002066,000004:                                                                                                  ## Purpose:     Part of the source code for Luminary 1A build 099.
002067,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM)
002068,000006:                                                                                                  ##              Apollo Guidance Computer (AGC), for Apollo 11.
002069,000007:                                                                                                  ## Assembler:   yaYUL
002070,000008:                                                                                                  ## Contact:     Onno Hommes <ohommes@cmu.edu>.
002071,000009:                                                                                                  ## Website:     www.ibiblio.org/apollo.
002072,000010:                                                                                                  ## Pages:       0054-0060
002073,000011:                                                                                                  ## Mod history: 2009-05-14 OH   Transcribed from page images.
002074,000012:                                                                                                  ##              2016-12-13 RSB  Proofed text comments with octopus/ProoferComments
002075,000013:                                                                                                  ##                              and corrected the errors found.
002076,000014:                                                                                                  ##              2017-03-02 RSB  Corrected various comment-text errors found whilst
002077,000015:                                                                                                  ##                              proofing Luminary 116.
002078,000016:                                                                                                  ##
002079,000017:                                                                                                  ## This source code has been transcribed or otherwise adapted from
002080,000018:                                                                                                  ## digitized images of a hardcopy from the MIT Museum.  The digitization
002081,000019:                                                                                                  ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
002082,000020:                                                                                                  ## the Museum.  Many thanks to both.  The images (with suitable reduction
002083,000021:                                                                                                  ## in storage size and consequent reduction in image quality as well) are
002084,000022:                                                                                                  ## available online at www.ibiblio.org/apollo.  If for some reason you
002085,000023:                                                                                                  ## find that the images are illegible, contact me at info@sandroid.org
002086,000024:                                                                                                  ## about getting access to the (much) higher-quality images which Paul
002087,000025:                                                                                                  ## actually created.
002088,000026:                                                                                                  ##
002089,000027:                                                                                                  ## Notations on the hardcopy document read, in part:
002090,000028:                                                                                                  ##
002091,000029:                                                                                                  ##      Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
002092,000030:                                                                                                  ##      16:27 JULY 14, 1969 
002093,000031: 

Page 54

002095,000033: 
002096,000034:                                                                                                  #  *** CHANNEL DESCRIPTIONSF WORDS ARE ALLOCATED IN ERASABLE ASSIGNMENTS ***
002097,000035: 
002098,000036:                                                                                                  #  CHANNEL 1     IDENTICAL TO COMPUTER REGISTER L (0001)
002099,000037: 
002100,000038:                                                                                                  #  CHANNEL 2     IDENTICAL TO COMPUTER REGISTER Q (0002)
002101,000039: 
002102,000040:                                                                                                  #  CHANNEL 3     HISCALAR; INPUT CHANNEL; MOST SIGNIFICANT 14 BITS FROM 33 STAGE BINARY COUNTER. SCALE
002103,000041:                                                                                                  #                FACTOR IS B23 IN CSEC, SO MAX VALUE ABOUT 23.3 HOURS AND LEAST SIGNIFICANT BIT 5.12 SECS.
002104,000042: 
002105,000043:                                                                                                  #  CHANNEL 4     LOSCALAR; INPUT CHANNEL; NEXT MOST SIGNIFICANT 14 BITS FROM THE 33 STAGE BINARY COUNTER
002106,000044:                                                                                                  #                ASSOCIATED WITH CHANNEL 3. SCALE FACTOR IS B9 IN CSEC. SO MAX VAL IS 5.12 SEC AND LEAST
002107,000045:                                                                                                  #                SIGNIFICANT BIT IS 1/3200 SEC. SCALE FACTOR OF D.P. WORD WITH CHANNEL 3 IS B23 CSEC.
002108,000046: 
002109,000047:                                                                                                  #  CHANNEL 5     PYJETS;  OUTPUT CHANNEL; PITCH RCS JET CONTROL.  (REACTION CONTROL SYSTEM) USES BITS 1-8.
002110,000048: 
002111,000049:                                                                                                  #  CHANNEL 6     ROLLJETS; OUTPUT CHANNEL; ROLL RCS JET CONTROL.  (REACTION CONTROL SYSTEM) USES BIT 1-8.
002112,000050: 
002113,000051:                                                                                                  #  CHANNEL 7     SUPERBNK; OUTPUT CHANNEL; NOT RESET BY RESTART; FIXED EXTENSION BITS USED TO SELECT THE
002114,000052:                                                                                                  #                APPROPRIATE FIXED MEMORY BANK IF FBANK IS 30 OCTAL OR MORE.  USES BITS 5-7.
002115,000053: 
002116,000054:                                                                                                  #  CHANNEL 10    OUTO; OUTPUT CHANNEL; REGISTER USED TO TRANSMIT LATCHING-RELAY DRIVING INFORMATION FOR
002117,000055:                                                                                                  #                THE DISPLAY SYSTEM.  BITS 15-12 ARE SET TO THE ROW NUMBER (1-14 OCTAL) OF THE RELAY TO BE
002118,000056:                                                                                                  #                CHANGED AND BITS 11-1 CONTAIN THE REQUIRED SETTINGS FOR THE RELAYS IN THE ROW.
002119,000057: 
002120,000058:                                                                                                  #  CHANNEL 11    DSALMOUT; OUTPUT CHANNEL; REGISTER WHOSE BITS ARE USED FOR ENGINE ON-OFF CONTROL AND TO
002121,000059:                                                                                                  #                DRIVE INDIVIDUAL INDICATORS OF THE DISPLAY SYSTEM.  BITS 1-7 ARE A RELAYS.
002122,000060: 
002123,000061:                                                                                                  #                BIT 1           ISS WARNING
002124,000062:                                                                                                  #                BIT 2           LIGHT COMPUTER ACTIVITY LAMP
002125,000063:                                                                                                  #                BIT 3           LIGHT UPLINK ACTIVITY LAMP
002126,000064:                                                                                                  #                BIT 4           LIGHT TEMP CAUTION LAMP
002127,000065:                                                                                                  #                BIT 5           LIGHT KEYBOARD RELEASE LAMP
002128,000066:                                                                                                  #                BIT 6           FLASH VERB AND NOUN LAMPS
002129,000067:                                                                                                  #                BIT 7           LIGHT OPERATOR ERROR LAMP

Page 55

002131,000069:                                                                                                  #                BIT 8           SPARE
002132,000070:                                                                                                  #                BIT 9           TEST CONNECTOR OUTBIT
002133,000071:                                                                                                  #                BIT 10          CAUTION RESET
002134,000072:                                                                                                  #                BIT 11          SPARE
002135,000073:                                                                                                  #                BIT 12          SPARE
002136,000074:                                                                                                  #                BIT 13          ENGINE ON
002137,000075:                                                                                                  #                BIT 14          ENGINE OFF
002138,000076:                                                                                                  #                BIT 15          SPARE
002139,000077: 
002140,000078:                                                                                                  #  CHANNEL 12    CHAN12; OUTPUT CHANNEL; BITS USED TO DRIVE NAVIGATION AND SPAECRAFT HARDWARE
002141,000079: 
002142,000080:                                                                                                  #                BIT 1           ZERO RR CDU; CDU'S GIVE RRADAR INFORMATION FOR LM
002143,000081:                                                                                                  #                BIT 2           ENABLE CDU RADAR ERROR COUNTERS
002144,000082:                                                                                                  #                BIT 3           NOT USED
002145,000083:                                                                                                  #                BIT 4           COARSE ALIGN ENABLE OF IMU
002146,000084:                                                                                                  #                BIT 5           ZERO IMU CDU'S
002147,000085:                                                                                                  #                BIT 6           ENABLE IMU ERROR COUNTER, CDU ERROR COUNTER.
002148,000086:                                                                                                  #                BIT 7           SPARE
002149,000087:                                                                                                  #                BIT 8           DISPLAY INERTIAL DATA
002150,000088:                                                                                                  #                BIT 9           -PITCH GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002151,000089:                                                                                                  #                BIT 10          +PITCH GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002152,000090:                                                                                                  #                BIT 11          -ROLL GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002153,000091:                                                                                                  #                BIT 12          +ROLL GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002154,000092:                                                                                                  #                BIT 13          LR POSITION 2 COMMAND
002155,000093:                                                                                                  #                BIT 14          ENABLE RENDESVOUS RADAR LOCK-ON; AUTO ANGLE TRACK'G
002156,000094:                                                                                                  #                BIT 15          ISS TURN ON DELAY COMPLETE
002157,000095: 

Page 56

002159,000097:                                                                                                  #  CHANNEL 13    CHAN13; OUTPUT CHANNEL
002160,000098: 
002161,000099:                                                                                                  #                BIT 1           RADAR C         PROPER SETTING OF THE A,B,C MATRIX
002162,000100:                                                                                                  #                BIT 2           RADAR B         SELECTS CERTAIN RADAR
002163,000101:                                                                                                  #                BIT 3           RADAR A         PARAMETERS TO BE READ.
002164,000102:                                                                                                  #                BIT 4           RADAR ACTIVITY
002165,000103:                                                                                                  #                BIT 5           NOT USED (CONNECTS AN ALTERNATE INPUT TO UPLINK)
002166,000104:                                                                                                  #                BIT 6           BLOCK INPUTS TO UPLINK CELL
002167,000105:                                                                                                  #                BIT 7           DOWNLINK TELEMETRY WORD ORDER CODE BIT
002168,000106:                                                                                                  #                BIT 8           RHC COUNTER ENABLE (READ HAND CONTROLLER ANGLES)
002169,000107:                                                                                                  #                BIT 9           START RHC READ INTO COUNTERS IF BIT 8 SET
002170,000108:                                                                                                  #                BIT 10          TEST ALARMS, TEST DSKY LIGHTS
002171,000109:                                                                                                  #                BIT 11          ENABLE STANDBY
002172,000110:                                                                                                  #                BIT 12          RESET TRAP 31-A         ALWAYS APPEAR TO BE SET TO 0
002173,000111:                                                                                                  #                BIT 13          RESET TRAP 31-B         ALWAYS APPEAR TO BE SET TO 0
002174,000112:                                                                                                  #                BIT 14          RESET TRAP 32           ALWAYS APPEAR TO BE SET TO 0
002175,000113:                                                                                                  #                BIT 15          ENABLE T6 RUPT
002176,000114: 
002177,000115:                                                                                                  #  CHANNEL 14    CHAN14; OUTPUT CHANNEL; USED TO CONTROL COMPUTER COUNTER CELLS (CDU, GYRO, SPACECRAFT FUNC.
002178,000116: 
002179,000117:                                                                                                  #                BIT 1           OUTLINK ACTIVITY (NOT USED)
002180,000118:                                                                                                  #                BIT 2           ALTITUDE RATE OR ALTITIDE SELECTOR
002181,000119:                                                                                                  #                BIT 3           ALTITUDE METER ACTIVITY
002182,000120:                                                                                                  #                BIT 4           THRUST DRIVE ACTIVITY FOR DESCENT ENGINE
002183,000121:                                                                                                  #                BIT 5           SPARE
002184,000122:                                                                                                  #                BIT 6           GYRO ENABLE POWER FOR PULSES
002185,000123:                                                                                                  #                BIT 7           GYRO SELECT B           PAIR OF BITS IDENTIFIES AXIS OF -
002186,000124:                                                                                                  #                BIT 8           GYRO SELECT A           GYRO SYSTEM TO BE TORQUED.
002187,000125:                                                                                                  #                BIT 9           GYRO TORQUING COMMAND IN NEGATIVE DIRECTION

Page 57

002189,000127:                                                                                                  #                BIT 10          GYRO ACTIVITY
002190,000128:                                                                                                  #                BIT 11          DRIVE CDU S
002191,000129:                                                                                                  #                BIT 12          DRIVE CDU T
002192,000130:                                                                                                  #                BIT 13          DRIVE CDU Z
002193,000131:                                                                                                  #                BIT 14          DRIVE CDU Y
002194,000132:                                                                                                  #                BIT 15          DRIVE CDU X
002195,000133: 
002196,000134:                                                                                                  #  CHANNEL 15    MNKEYIN; INPUT CHANNEL; KEY CODE INPUT FROM KEYBOARD OF DSKY, SENSED BY PROGRAM WHEN
002197,000135:                                                                                                  #                PROGRAM INTERRUPT #5 IS RECEIVED.  USES BITS 5-1
002198,000136: 
002199,000137:                                                                                                  #  CHANNEL 16    NAVKEYIN; INPUT CHANNEL; OPTICS MARK INFORMATION AND NAVIGA ION PANEL DSKY (CM) OR THRUST
002200,000138:                                                                                                  #                CONTROL (LM) SENSED BY PROGRAM WHEN PROGRAM INTER-RUPT #6 IS RECEIVED.  USES BITS 3-7 ONLY.
002201,000139: 
002202,000140:                                                                                                  #                BIT 1           NOT ASSIGNED
002203,000141:                                                                                                  #                BIT 2           NOT ASSIGNED
002204,000142:                                                                                                  #                BIT 3           OPTICS X-AXIS MARK SIGNAL FOR ALIGN OPTICAL TSCOPE
002205,000143:                                                                                                  #                BIT 4           OPTICS Y-AXIS MARK SIGNAL FOR AOT
002206,000144:                                                                                                  #                BIT 5           OPTICS MARK REJECT SIGNAL
002207,000145:                                                                                                  #                BIT 6           DESCENT+ ; CREW DESIRED SLOWING RATE OF DESCENT
002208,000146:                                                                                                  #                BIT 7           DESCENT- ; CREW DESIRED SPEEDING UP RATE OF D'CENT
002209,000147: 
002210,000148:                                                                                                  #  NOTE: ALL BITS IN CHANNELS 30-33 ARE INVERTED AS SENSED BY THE PROGRAM, SO THAT A VALUE OF ZERO MEANS
002211,000149:                                                                                                  #  THAT THE INDICATED SIGNAL IS PRESENT.
002212,000150: 
002213,000151:                                                                                                  #  CHANNEL 30    INPUT CHANNEL
002214,000152: 
002215,000153:                                                                                                  #                BIT 1           ABORT WITH DESCENT STAGE
002216,000154:                                                                                                  #                BIT 2           UNUSED
002217,000155:                                                                                                  #                BIT 3           ENGINE ARMED SIGNAL
002218,000156:                                                                                                  #                BIT 4           ABORT WITH ASCENT ENGINE STAGE
002219,000157:                                                                                                  #                BIT 5           AUTO THROTTLE; COMPUTER CONTROL OF DESCENT ENGINE

Page 58

002221,000159:                                                                                                  #                BIT 6           DISPLAY INERTIAL DATA
002222,000160:                                                                                                  #                BIT 7           RR CDU FAIL
002223,000161:                                                                                                  #                BIT 8           SPARE
002224,000162:                                                                                                  #                BIT 9           IMU OPERATE WITH NO MALFUNCTION
002225,000163:                                                                                                  #                BIT 10          LM COMPUTER (NOT AGS) HAS CONTROL OF LM
002226,000164:                                                                                                  #                BIT 11          IMU CAGE COMMAND TO DRIVE IMU GIMBAL ANGLES TO 0.
002227,000165:                                                                                                  #                BIT 12          IMU CDU FAIL (MALFUNCTION OF IMU CDU,S)
002228,000166:                                                                                                  #                BIT 13          IMU FAIL (MALFUNCTION OF IMU STABILIZATION LOOPS)
002229,000167:                                                                                                  #                BIT 14          ISS TURN ON REQUESTED
002230,000168:                                                                                                  #                BIT 15          TEMPERATURE OF STABLE MEMBER WITHIN DESIGN LIMITS
002231,000169: 
002232,000170:                                                                                                  #  CHANNEL 31    INPUT CHANNEL; BITS ASSOCIATED WITH THE ATTITUDE CONTROLLER, TRANSLATIONAL CONTROLLER,
002233,000171:                                                                                                  #                AND SPACECRAFT ATTITUDE CONTROL; USED BY RCS DAP
002234,000172: 
002235,000173:                                                                                                  #                BIT 1           ROTATION (BY RHC) COMMANDED IN POSITIVE PITCH DIRECTION; MUST BE IN MINIMUM IMPULSE MODE.
002236,000174:                                                                                                  #                                ALSO POSITIVE ELEVATION CHANGE FOR LANDING POINT DESIGNATOR
002237,000175:                                                                                                  #                BIT 2           AS BIT 1 EXCEPT NEGATIVE PITCH AND ELEVATION
002238,000176:                                                                                                  #                BIT 3           ROTATION (BY RHC) COMMANDED IN POSITIVE YAW DIRECTION; MUST BE IN MINUMUM IMPULSE MODE.
002239,000177:                                                                                                  #                BIT 4           AS BIT 3 EXCEPT NEGATIVE YAW
002240,000178:                                                                                                  #                BIT 5           ROTATION (BY RHC) COMMANDED IN POSITIVE ROLL DIRECTION; MUST BE IN MINIMUM IMPULSE MODE.
002241,000179:                                                                                                  #                                ALSO POSITIVE AZIMUTH CHANGE FOR LANDING POINT DESIGNATOR
002242,000180:                                                                                                  #                BIT 6           AS BIT 5 EXCEPT NEGATIVE ROLL AND AZIMUTH
002243,000181:                                                                                                  #                BIT 7           TRANSLATION IN +X DIRECTION COMMANDED BY THC
002244,000182:                                                                                                  #                BIT 8           TRANSLATION IN -X DIRECTION COMMANDED BY THC
002245,000183:                                                                                                  #                BIT 9           TRANSLATION IN +Y DIRECTION COMMANDED BY THC
002246,000184:                                                                                                  #                BIT 10          TRANSLATION IN -Y DIRECTION COMMANDED BY THC
002247,000185:                                                                                                  #                BIT 11          TRANSLATION IN +Z DIRECTION COMMANDED BY THC
002248,000186:                                                                                                  #                BIT 12          TRANSLATION IN -Z DIRECTION COMMANDED BY THC

Page 59

002250,000188:                                                                                                  #                BIT 13          ATTITUDE HOLD MODE ON SCS MODE CONTROL SWITCH
002251,000189:                                                                                                  #                BIT 14          AUTO STABILIZATION OF ATTITUDE ON SCS MODE SWITCH
002252,000190:                                                                                                  #                BIT 15          ATTITUDE CONTROL OUT OF DETENT (RHC NOT IN NEUTRAL
002253,000191: 
002254,000192:                                                                                                  #  CHANNEL 32    INPUT CHANNEL.
002255,000193: 
002256,000194:                                                                                                  #                BIT 1           THRUSTERS 2 & 4 DISABLED BY CREW
002257,000195:                                                                                                  #                BIT 2           THRUSTERS 5 & 8 DISABLED BY CREW
002258,000196:                                                                                                  #                BIT 3           THRUSTERS 1 & 3 DISABLED BY CREW
002259,000197:                                                                                                  #                BIT 4           THRUSTERS 6 & 7 DISABLED BY CREW
002260,000198:                                                                                                  #                BIT 5           THRUSTERS 14 & 16 DISABLED BY CREW
002261,000199:                                                                                                  #                BIT 6           THRUSTERS 13 & 15 DISABLED BY CREW
002262,000200:                                                                                                  #                BIT 7           THRUSTERS 9 & 12 DISABLED BY CREW
002263,000201:                                                                                                  #                BIT 8           THRUSTERS 10 & 11 DISABLED BY CREW
002264,000202:                                                                                                  #                BIT 9           DESCENT ENGINE GIMBALS DISABLED BY CREW
002265,000203:                                                                                                  #                BIT 10          APPARENT DESCENT ENGINE GIMBAL FAILURE
002266,000204:                                                                                                  #                BIT 14          INDICATES PROCEED KEY IS DEPRESSED
002267,000205: 
002268,000206:                                                                                                  #  CHANNEL 33    CHAN33; INPUT CHANNEL; FOR HARDWARE STATUS AND COMMAND INFORMATION.  BITS 15-11 ARE FLIP-
002269,000207:                                                                                                  #                FLOP BITS RESET BY A CHANNEL "WRITE" COMMAND THAT ARE RESET BY A RESTART & BY T4RUPT LOOP.
002270,000208: 
002271,000209:                                                                                                  #                BIT 1           SPARE
002272,000210:                                                                                                  #                BIT 2           RR AUTO-POWER ON
002273,000211:                                                                                                  #                BIT 3           RR RANGE LOW SCALE
002274,000212:                                                                                                  #                BIT 4           RR DATA GOOD
002275,000213:                                                                                                  #                BIT 5           LR RANGE DATA GOOD
002276,000214:                                                                                                  #                BIT 6           LR POS1
002277,000215:                                                                                                  #                BIT 7           LR POS2

Page 60

002279,000217:                                                                                                  #                BIT 8           LR VEL DATA GOOD
002280,000218:                                                                                                  #                BIT 9           LR RANGE LOW SCALE
002281,000219:                                                                                                  #                BIT 10          BLOCK UPLINK INPUT
002282,000220:                                                                                                  #                BIT 11          UPLINK TOO FAST
002283,000221:                                                                                                  #                BIT 12          DOWNLINK TOO FAST
002284,000222:                                                                                                  #                BIT 13          PIPA FAIL
002285,000223:                                                                                                  #                BIT 14          WARNING OF REPEATED ALARMS: RESTART, COUNTER FAIL, VOLTAGE FAIL, AND SCALAR DOUBLE.
002286,000224:                                                                                                  #                BIT 15          LGC OSCILLATOR STOPPED
002287,000225: 
002288,000226:                                                                                                  #  CHANNEL 34    DNT M1; OUTPUT CHANNEL; DOWNLINK 1  FIRST OF TWO WORDS SERIALIZATION.
002289,000227:                                                                                                  #  CHANNEL 35    DNT M2; OUTPUT CHANNEL DOWNLINK 2 SOCOND OF TWO   WORDS SERIALIZATION.
002290,000228: 
002291,000229: 

End of include-file INPUT_OUTPUT_CHANNEL_BIT_DESCRIPTIONS.agc.  Parent file is MAIN.agc