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.

002072,000002:                                                                                                  ## Copyright:   Public domain.
002073,000003:                                                                                                  ## Filename:    INPUT_OUTPUT_CHANNEL_BIT_DESCRIPTIONS.agc
002074,000004:                                                                                                  ## Purpose:     Part of the source code for Luminary 1A build 099.
002075,000005:                                                                                                  ##              It is part of the source code for the Lunar Module's (LM)
002076,000006:                                                                                                  ##              Apollo Guidance Computer (AGC), for Apollo 11.
002077,000007:                                                                                                  ## Assembler:   yaYUL
002078,000008:                                                                                                  ## Contact:     Onno Hommes <ohommes@cmu.edu>.
002079,000009:                                                                                                  ## Website:     www.ibiblio.org/apollo.
002080,000010:                                                                                                  ## Pages:       0054-0060
002081,000011:                                                                                                  ## Mod history: 2009-05-14 OH   Transcribed from page images.
002082,000012:                                                                                                  ##              2016-12-13 RSB  Proofed text comments with octopus/ProoferComments
002083,000013:                                                                                                  ##                              and corrected the errors found.
002084,000014:                                                                                                  ##              2017-03-02 RSB  Corrected various comment-text errors found whilst
002085,000015:                                                                                                  ##                              proofing Luminary 116.
002086,000016:                                                                                                  ##
002087,000017:                                                                                                  ## This source code has been transcribed or otherwise adapted from
002088,000018:                                                                                                  ## digitized images of a hardcopy from the MIT Museum.  The digitization
002089,000019:                                                                                                  ## was performed by Paul Fjeld, and arranged for by Deborah Douglas of
002090,000020:                                                                                                  ## the Museum.  Many thanks to both.  The images (with suitable reduction
002091,000021:                                                                                                  ## in storage size and consequent reduction in image quality as well) are
002092,000022:                                                                                                  ## available online at www.ibiblio.org/apollo.  If for some reason you
002093,000023:                                                                                                  ## find that the images are illegible, contact me at info@sandroid.org
002094,000024:                                                                                                  ## about getting access to the (much) higher-quality images which Paul
002095,000025:                                                                                                  ## actually created.
002096,000026:                                                                                                  ##
002097,000027:                                                                                                  ## Notations on the hardcopy document read, in part:
002098,000028:                                                                                                  ##
002099,000029:                                                                                                  ##      Assemble revision 001 of AGC program LMY99 by NASA 2021112-61
002100,000030:                                                                                                  ##      16:27 JULY 14, 1969 
002101,000031: 

Page 54

002103,000033: 
002104,000034:                                                                                                  #  *** CHANNEL DESCRIPTIONSF WORDS ARE ALLOCATED IN ERASABLE ASSIGNMENTS ***
002105,000035: 
002106,000036:                                                                                                  #  CHANNEL 1     IDENTICAL TO COMPUTER REGISTER L (0001)
002107,000037: 
002108,000038:                                                                                                  #  CHANNEL 2     IDENTICAL TO COMPUTER REGISTER Q (0002)
002109,000039: 
002110,000040:                                                                                                  #  CHANNEL 3     HISCALAR; INPUT CHANNEL; MOST SIGNIFICANT 14 BITS FROM 33 STAGE BINARY COUNTER. SCALE
002111,000041:                                                                                                  #                FACTOR IS B23 IN CSEC, SO MAX VALUE ABOUT 23.3 HOURS AND LEAST SIGNIFICANT BIT 5.12 SECS.
002112,000042: 
002113,000043:                                                                                                  #  CHANNEL 4     LOSCALAR; INPUT CHANNEL; NEXT MOST SIGNIFICANT 14 BITS FROM THE 33 STAGE BINARY COUNTER
002114,000044:                                                                                                  #                ASSOCIATED WITH CHANNEL 3. SCALE FACTOR IS B9 IN CSEC. SO MAX VAL IS 5.12 SEC AND LEAST
002115,000045:                                                                                                  #                SIGNIFICANT BIT IS 1/3200 SEC. SCALE FACTOR OF D.P. WORD WITH CHANNEL 3 IS B23 CSEC.
002116,000046: 
002117,000047:                                                                                                  #  CHANNEL 5     PYJETS;  OUTPUT CHANNEL; PITCH RCS JET CONTROL.  (REACTION CONTROL SYSTEM) USES BITS 1-8.
002118,000048: 
002119,000049:                                                                                                  #  CHANNEL 6     ROLLJETS; OUTPUT CHANNEL; ROLL RCS JET CONTROL.  (REACTION CONTROL SYSTEM) USES BIT 1-8.
002120,000050: 
002121,000051:                                                                                                  #  CHANNEL 7     SUPERBNK; OUTPUT CHANNEL; NOT RESET BY RESTART; FIXED EXTENSION BITS USED TO SELECT THE
002122,000052:                                                                                                  #                APPROPRIATE FIXED MEMORY BANK IF FBANK IS 30 OCTAL OR MORE.  USES BITS 5-7.
002123,000053: 
002124,000054:                                                                                                  #  CHANNEL 10    OUTO; OUTPUT CHANNEL; REGISTER USED TO TRANSMIT LATCHING-RELAY DRIVING INFORMATION FOR
002125,000055:                                                                                                  #                THE DISPLAY SYSTEM.  BITS 15-12 ARE SET TO THE ROW NUMBER (1-14 OCTAL) OF THE RELAY TO BE
002126,000056:                                                                                                  #                CHANGED AND BITS 11-1 CONTAIN THE REQUIRED SETTINGS FOR THE RELAYS IN THE ROW.
002127,000057: 
002128,000058:                                                                                                  #  CHANNEL 11    DSALMOUT; OUTPUT CHANNEL; REGISTER WHOSE BITS ARE USED FOR ENGINE ON-OFF CONTROL AND TO
002129,000059:                                                                                                  #                DRIVE INDIVIDUAL INDICATORS OF THE DISPLAY SYSTEM.  BITS 1-7 ARE A RELAYS.
002130,000060: 
002131,000061:                                                                                                  #                BIT 1           ISS WARNING
002132,000062:                                                                                                  #                BIT 2           LIGHT COMPUTER ACTIVITY LAMP
002133,000063:                                                                                                  #                BIT 3           LIGHT UPLINK ACTIVITY LAMP
002134,000064:                                                                                                  #                BIT 4           LIGHT TEMP CAUTION LAMP
002135,000065:                                                                                                  #                BIT 5           LIGHT KEYBOARD RELEASE LAMP
002136,000066:                                                                                                  #                BIT 6           FLASH VERB AND NOUN LAMPS
002137,000067:                                                                                                  #                BIT 7           LIGHT OPERATOR ERROR LAMP

Page 55

002139,000069:                                                                                                  #                BIT 8           SPARE
002140,000070:                                                                                                  #                BIT 9           TEST CONNECTOR OUTBIT
002141,000071:                                                                                                  #                BIT 10          CAUTION RESET
002142,000072:                                                                                                  #                BIT 11          SPARE
002143,000073:                                                                                                  #                BIT 12          SPARE
002144,000074:                                                                                                  #                BIT 13          ENGINE ON
002145,000075:                                                                                                  #                BIT 14          ENGINE OFF
002146,000076:                                                                                                  #                BIT 15          SPARE
002147,000077: 
002148,000078:                                                                                                  #  CHANNEL 12    CHAN12; OUTPUT CHANNEL; BITS USED TO DRIVE NAVIGATION AND SPAECRAFT HARDWARE
002149,000079: 
002150,000080:                                                                                                  #                BIT 1           ZERO RR CDU; CDU'S GIVE RRADAR INFORMATION FOR LM
002151,000081:                                                                                                  #                BIT 2           ENABLE CDU RADAR ERROR COUNTERS
002152,000082:                                                                                                  #                BIT 3           NOT USED
002153,000083:                                                                                                  #                BIT 4           COARSE ALIGN ENABLE OF IMU
002154,000084:                                                                                                  #                BIT 5           ZERO IMU CDU'S
002155,000085:                                                                                                  #                BIT 6           ENABLE IMU ERROR COUNTER, CDU ERROR COUNTER.
002156,000086:                                                                                                  #                BIT 7           SPARE
002157,000087:                                                                                                  #                BIT 8           DISPLAY INERTIAL DATA
002158,000088:                                                                                                  #                BIT 9           -PITCH GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002159,000089:                                                                                                  #                BIT 10          +PITCH GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002160,000090:                                                                                                  #                BIT 11          -ROLL GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002161,000091:                                                                                                  #                BIT 12          +ROLL GIMBAL TRIM (BELL MOTION) DESCENT ENGINE
002162,000092:                                                                                                  #                BIT 13          LR POSITION 2 COMMAND
002163,000093:                                                                                                  #                BIT 14          ENABLE RENDESVOUS RADAR LOCK-ON; AUTO ANGLE TRACK'G
002164,000094:                                                                                                  #                BIT 15          ISS TURN ON DELAY COMPLETE
002165,000095: 

Page 56

002167,000097:                                                                                                  #  CHANNEL 13    CHAN13; OUTPUT CHANNEL
002168,000098: 
002169,000099:                                                                                                  #                BIT 1           RADAR C         PROPER SETTING OF THE A,B,C MATRIX
002170,000100:                                                                                                  #                BIT 2           RADAR B         SELECTS CERTAIN RADAR
002171,000101:                                                                                                  #                BIT 3           RADAR A         PARAMETERS TO BE READ.
002172,000102:                                                                                                  #                BIT 4           RADAR ACTIVITY
002173,000103:                                                                                                  #                BIT 5           NOT USED (CONNECTS AN ALTERNATE INPUT TO UPLINK)
002174,000104:                                                                                                  #                BIT 6           BLOCK INPUTS TO UPLINK CELL
002175,000105:                                                                                                  #                BIT 7           DOWNLINK TELEMETRY WORD ORDER CODE BIT
002176,000106:                                                                                                  #                BIT 8           RHC COUNTER ENABLE (READ HAND CONTROLLER ANGLES)
002177,000107:                                                                                                  #                BIT 9           START RHC READ INTO COUNTERS IF BIT 8 SET
002178,000108:                                                                                                  #                BIT 10          TEST ALARMS, TEST DSKY LIGHTS
002179,000109:                                                                                                  #                BIT 11          ENABLE STANDBY
002180,000110:                                                                                                  #                BIT 12          RESET TRAP 31-A         ALWAYS APPEAR TO BE SET TO 0
002181,000111:                                                                                                  #                BIT 13          RESET TRAP 31-B         ALWAYS APPEAR TO BE SET TO 0
002182,000112:                                                                                                  #                BIT 14          RESET TRAP 32           ALWAYS APPEAR TO BE SET TO 0
002183,000113:                                                                                                  #                BIT 15          ENABLE T6 RUPT
002184,000114: 
002185,000115:                                                                                                  #  CHANNEL 14    CHAN14; OUTPUT CHANNEL; USED TO CONTROL COMPUTER COUNTER CELLS (CDU, GYRO, SPACECRAFT FUNC.
002186,000116: 
002187,000117:                                                                                                  #                BIT 1           OUTLINK ACTIVITY (NOT USED)
002188,000118:                                                                                                  #                BIT 2           ALTITUDE RATE OR ALTITIDE SELECTOR
002189,000119:                                                                                                  #                BIT 3           ALTITUDE METER ACTIVITY
002190,000120:                                                                                                  #                BIT 4           THRUST DRIVE ACTIVITY FOR DESCENT ENGINE
002191,000121:                                                                                                  #                BIT 5           SPARE
002192,000122:                                                                                                  #                BIT 6           GYRO ENABLE POWER FOR PULSES
002193,000123:                                                                                                  #                BIT 7           GYRO SELECT B           PAIR OF BITS IDENTIFIES AXIS OF -
002194,000124:                                                                                                  #                BIT 8           GYRO SELECT A           GYRO SYSTEM TO BE TORQUED.
002195,000125:                                                                                                  #                BIT 9           GYRO TORQUING COMMAND IN NEGATIVE DIRECTION

Page 57

002197,000127:                                                                                                  #                BIT 10          GYRO ACTIVITY
002198,000128:                                                                                                  #                BIT 11          DRIVE CDU S
002199,000129:                                                                                                  #                BIT 12          DRIVE CDU T
002200,000130:                                                                                                  #                BIT 13          DRIVE CDU Z
002201,000131:                                                                                                  #                BIT 14          DRIVE CDU Y
002202,000132:                                                                                                  #                BIT 15          DRIVE CDU X
002203,000133: 
002204,000134:                                                                                                  #  CHANNEL 15    MNKEYIN; INPUT CHANNEL; KEY CODE INPUT FROM KEYBOARD OF DSKY, SENSED BY PROGRAM WHEN
002205,000135:                                                                                                  #                PROGRAM INTERRUPT #5 IS RECEIVED.  USES BITS 5-1
002206,000136: 
002207,000137:                                                                                                  #  CHANNEL 16    NAVKEYIN; INPUT CHANNEL; OPTICS MARK INFORMATION AND NAVIGA ION PANEL DSKY (CM) OR THRUST
002208,000138:                                                                                                  #                CONTROL (LM) SENSED BY PROGRAM WHEN PROGRAM INTER-RUPT #6 IS RECEIVED.  USES BITS 3-7 ONLY.
002209,000139: 
002210,000140:                                                                                                  #                BIT 1           NOT ASSIGNED
002211,000141:                                                                                                  #                BIT 2           NOT ASSIGNED
002212,000142:                                                                                                  #                BIT 3           OPTICS X-AXIS MARK SIGNAL FOR ALIGN OPTICAL TSCOPE
002213,000143:                                                                                                  #                BIT 4           OPTICS Y-AXIS MARK SIGNAL FOR AOT
002214,000144:                                                                                                  #                BIT 5           OPTICS MARK REJECT SIGNAL
002215,000145:                                                                                                  #                BIT 6           DESCENT+ ; CREW DESIRED SLOWING RATE OF DESCENT
002216,000146:                                                                                                  #                BIT 7           DESCENT- ; CREW DESIRED SPEEDING UP RATE OF D'CENT
002217,000147: 
002218,000148:                                                                                                  #  NOTE: ALL BITS IN CHANNELS 30-33 ARE INVERTED AS SENSED BY THE PROGRAM, SO THAT A VALUE OF ZERO MEANS
002219,000149:                                                                                                  #  THAT THE INDICATED SIGNAL IS PRESENT.
002220,000150: 
002221,000151:                                                                                                  #  CHANNEL 30    INPUT CHANNEL
002222,000152: 
002223,000153:                                                                                                  #                BIT 1           ABORT WITH DESCENT STAGE
002224,000154:                                                                                                  #                BIT 2           UNUSED
002225,000155:                                                                                                  #                BIT 3           ENGINE ARMED SIGNAL
002226,000156:                                                                                                  #                BIT 4           ABORT WITH ASCENT ENGINE STAGE
002227,000157:                                                                                                  #                BIT 5           AUTO THROTTLE; COMPUTER CONTROL OF DESCENT ENGINE

Page 58

002229,000159:                                                                                                  #                BIT 6           DISPLAY INERTIAL DATA
002230,000160:                                                                                                  #                BIT 7           RR CDU FAIL
002231,000161:                                                                                                  #                BIT 8           SPARE
002232,000162:                                                                                                  #                BIT 9           IMU OPERATE WITH NO MALFUNCTION
002233,000163:                                                                                                  #                BIT 10          LM COMPUTER (NOT AGS) HAS CONTROL OF LM
002234,000164:                                                                                                  #                BIT 11          IMU CAGE COMMAND TO DRIVE IMU GIMBAL ANGLES TO 0.
002235,000165:                                                                                                  #                BIT 12          IMU CDU FAIL (MALFUNCTION OF IMU CDU,S)
002236,000166:                                                                                                  #                BIT 13          IMU FAIL (MALFUNCTION OF IMU STABILIZATION LOOPS)
002237,000167:                                                                                                  #                BIT 14          ISS TURN ON REQUESTED
002238,000168:                                                                                                  #                BIT 15          TEMPERATURE OF STABLE MEMBER WITHIN DESIGN LIMITS
002239,000169: 
002240,000170:                                                                                                  #  CHANNEL 31    INPUT CHANNEL; BITS ASSOCIATED WITH THE ATTITUDE CONTROLLER, TRANSLATIONAL CONTROLLER,
002241,000171:                                                                                                  #                AND SPACECRAFT ATTITUDE CONTROL; USED BY RCS DAP
002242,000172: 
002243,000173:                                                                                                  #                BIT 1           ROTATION (BY RHC) COMMANDED IN POSITIVE PITCH DIRECTION; MUST BE IN MINIMUM IMPULSE MODE.
002244,000174:                                                                                                  #                                ALSO POSITIVE ELEVATION CHANGE FOR LANDING POINT DESIGNATOR
002245,000175:                                                                                                  #                BIT 2           AS BIT 1 EXCEPT NEGATIVE PITCH AND ELEVATION
002246,000176:                                                                                                  #                BIT 3           ROTATION (BY RHC) COMMANDED IN POSITIVE YAW DIRECTION; MUST BE IN MINUMUM IMPULSE MODE.
002247,000177:                                                                                                  #                BIT 4           AS BIT 3 EXCEPT NEGATIVE YAW
002248,000178:                                                                                                  #                BIT 5           ROTATION (BY RHC) COMMANDED IN POSITIVE ROLL DIRECTION; MUST BE IN MINIMUM IMPULSE MODE.
002249,000179:                                                                                                  #                                ALSO POSITIVE AZIMUTH CHANGE FOR LANDING POINT DESIGNATOR
002250,000180:                                                                                                  #                BIT 6           AS BIT 5 EXCEPT NEGATIVE ROLL AND AZIMUTH
002251,000181:                                                                                                  #                BIT 7           TRANSLATION IN +X DIRECTION COMMANDED BY THC
002252,000182:                                                                                                  #                BIT 8           TRANSLATION IN -X DIRECTION COMMANDED BY THC
002253,000183:                                                                                                  #                BIT 9           TRANSLATION IN +Y DIRECTION COMMANDED BY THC
002254,000184:                                                                                                  #                BIT 10          TRANSLATION IN -Y DIRECTION COMMANDED BY THC
002255,000185:                                                                                                  #                BIT 11          TRANSLATION IN +Z DIRECTION COMMANDED BY THC
002256,000186:                                                                                                  #                BIT 12          TRANSLATION IN -Z DIRECTION COMMANDED BY THC

Page 59

002258,000188:                                                                                                  #                BIT 13          ATTITUDE HOLD MODE ON SCS MODE CONTROL SWITCH
002259,000189:                                                                                                  #                BIT 14          AUTO STABILIZATION OF ATTITUDE ON SCS MODE SWITCH
002260,000190:                                                                                                  #                BIT 15          ATTITUDE CONTROL OUT OF DETENT (RHC NOT IN NEUTRAL
002261,000191: 
002262,000192:                                                                                                  #  CHANNEL 32    INPUT CHANNEL.
002263,000193: 
002264,000194:                                                                                                  #                BIT 1           THRUSTERS 2 & 4 DISABLED BY CREW
002265,000195:                                                                                                  #                BIT 2           THRUSTERS 5 & 8 DISABLED BY CREW
002266,000196:                                                                                                  #                BIT 3           THRUSTERS 1 & 3 DISABLED BY CREW
002267,000197:                                                                                                  #                BIT 4           THRUSTERS 6 & 7 DISABLED BY CREW
002268,000198:                                                                                                  #                BIT 5           THRUSTERS 14 & 16 DISABLED BY CREW
002269,000199:                                                                                                  #                BIT 6           THRUSTERS 13 & 15 DISABLED BY CREW
002270,000200:                                                                                                  #                BIT 7           THRUSTERS 9 & 12 DISABLED BY CREW
002271,000201:                                                                                                  #                BIT 8           THRUSTERS 10 & 11 DISABLED BY CREW
002272,000202:                                                                                                  #                BIT 9           DESCENT ENGINE GIMBALS DISABLED BY CREW
002273,000203:                                                                                                  #                BIT 10          APPARENT DESCENT ENGINE GIMBAL FAILURE
002274,000204:                                                                                                  #                BIT 14          INDICATES PROCEED KEY IS DEPRESSED
002275,000205: 
002276,000206:                                                                                                  #  CHANNEL 33    CHAN33; INPUT CHANNEL; FOR HARDWARE STATUS AND COMMAND INFORMATION.  BITS 15-11 ARE FLIP-
002277,000207:                                                                                                  #                FLOP BITS RESET BY A CHANNEL "WRITE" COMMAND THAT ARE RESET BY A RESTART & BY T4RUPT LOOP.
002278,000208: 
002279,000209:                                                                                                  #                BIT 1           SPARE
002280,000210:                                                                                                  #                BIT 2           RR AUTO-POWER ON
002281,000211:                                                                                                  #                BIT 3           RR RANGE LOW SCALE
002282,000212:                                                                                                  #                BIT 4           RR DATA GOOD
002283,000213:                                                                                                  #                BIT 5           LR RANGE DATA GOOD
002284,000214:                                                                                                  #                BIT 6           LR POS1
002285,000215:                                                                                                  #                BIT 7           LR POS2

Page 60

002287,000217:                                                                                                  #                BIT 8           LR VEL DATA GOOD
002288,000218:                                                                                                  #                BIT 9           LR RANGE LOW SCALE
002289,000219:                                                                                                  #                BIT 10          BLOCK UPLINK INPUT
002290,000220:                                                                                                  #                BIT 11          UPLINK TOO FAST
002291,000221:                                                                                                  #                BIT 12          DOWNLINK TOO FAST
002292,000222:                                                                                                  #                BIT 13          PIPA FAIL
002293,000223:                                                                                                  #                BIT 14          WARNING OF REPEATED ALARMS: RESTART, COUNTER FAIL, VOLTAGE FAIL, AND SCALAR DOUBLE.
002294,000224:                                                                                                  #                BIT 15          LGC OSCILLATOR STOPPED
002295,000225: 
002296,000226:                                                                                                  #  CHANNEL 34    DNT M1; OUTPUT CHANNEL; DOWNLINK 1  FIRST OF TWO WORDS SERIALIZATION.
002297,000227:                                                                                                  #  CHANNEL 35    DNT M2; OUTPUT CHANNEL DOWNLINK 2 SOCOND OF TWO   WORDS SERIALIZATION.
002298,000228: 
002299,000229: 

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