Sequential Circuits Prophet-5 Service Manual - Audiofanzine

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I3JIJThe Prophet will not accept status bytes during its TUNE routine. During TUNE, DATAFROM transmits a BREAK signal to tell the sequencer the Prophet isn't listening. TheBREAK is simply a continuous low on DATA FROM. In other words, your receiver willsee a start bit followed by no stop bit. The break can therefore be detected by countingat least two framing errors with zero as data received.used to inhibit the sequencer.The BREAK can therefore be9-
T .1 T LFor the most transparent operation, you will want a minimum of time between bytestransmitted to the Prophet, The faster the transfer, the truer the timing will be. Somespecific timing figures may be of use. For example, the Prophet's scan time (for eachprogram loop) is 6 ms, or 11 ms if controls are being used. This means there is a worstcasedelay of 1 1 ms between a key being pressed and its being heard or recorded. This isnot normally detectable in the Prophet. However, sequencing adds new timing concerns,since the Prophet waits for the transfer to be completed before continuing its loop.With a 625 kHz clock, 9 serially-formatted bytes will take only 158,^ us (1.6 us X 99bits). But if they are spaced 1 ms apart, the whole transfer will about double the worstcaseloop time. It is more reasonable to use the fastest clock possible, and allow up to100 us between bytes. This will have a negligible effect on the Prophet's loop.The Prophet isprotected from being "hung-up" by extremely slow or nonexistent data.Its time-out software declares an error and ignores the whole message if more thanabout k milliseconds elapses between bytes.When the message iscomplete, the Prophet places this data into its "Scratchpad" RAMtable, playing the notes as if they came from its own keyboard. Even while receivingfrom the external sequencer the Prophet's keyboard remains active and can be usednormally (unless the sequencer TRANSPOSE function is enabled, see STATUS 2). Ofcourse you still have a five-voice maximum. So if you, for example, play on thekeyboard while the sequencer is playing, you will "steal" voices from the sequence.If no program change is desired, you can either transmit the last program number, orthe code FF(H) which the Prophet simply ignores. Except for the FF code, the Prophetwill sense an error ifeither of the two MSBs of the program byte are set.NOTE. Be sure the Prophet is switched to PRESET mode when you want to changeprograms.(Status B can be used for changing the program only ."short" keyboard data. See below.)Status E can be used for receiving9-6 STATUS 2: TRANSPOSE ONThis status byte isused to enable the sequencer transpose function. Once the Prophetreceives code 0^(H), you can transpose the entire playback sequence over a four-octaverange by just hitting a key between CO and C^ on the Prophet. The transposition isequal to the interval between C2 and the key played. For example, to transpose down afifth, hit Fl. To transpose up a major seventh from the original key, hit B2. Totranspose back to the original key, hit C2.9-7 STATUS 3: SAVE TO TAPEThis status byte isused to extract the contents of the Non-Volatile program RAM fromthe Prophet, without using the independent CASSETTE interface. Organized as ^0 2^byteprograms, NV RAM uses 960 of its102^ (IK) bytes. The least-significant seven bitsof each byte represent a programmable pot setting of -127 steps, while the MSBrepresents a switch setting (l=on, O=off), The Prophet has another area of RAM called"Scratchpad" in which the current status of the machine isregistered. When selecting aprogram in PRESET mode, a set of 2^ bytes is transferred from NV RAM to theScratchpad, with the "pot" bits filling the pot table and the switch bits being regroupedinto the switch status table. Here is how the pot and switch bits are grouped in each NVprogram:9-^TMiOOOD.2 10/81
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PROPHET-5 SYNTHESIZERTECHNICAL MANU
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iJTable of ContentsISECTION 1MECHAN
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'1SECTION 1MECHANICAL1-0 GENERALThi
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Raise the top panel assembly to ser
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1-5 PCB 1/2 CONTROL PANELSOnce PCB
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Figure 1-5KEYBOARD REMOVAL1 -7/1 -8
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TOADDITIONALVCOsTOADDITIONALENV GEN
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2-2 THE PROPHETThe Prophet is a sub
Page 19 and 20:
COMMON ANALOGVOICE(VOiCES e-5 ARE S
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'IAll processed CVs originate from
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ajMim—2-8 AUDIO OUTPUTAs shown in
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.'2-10 MICROPROCESSOR, MEMORY, AND
Page 27 and 28:
For troubleshooting, it should be e
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2-12 ADC, DAC, AND CV OUTPUTSThe DA
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iirH- - jMg 1— -^ 'iVMUX, U201-3^
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the same CV and trigger pattern to
Page 35 and 36:
SECTION 3DOCUMENTS3-0 DOCUMENT LIST
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TOP PANEL ASSEMBLY1CHASSiSLAST \NOT
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TB/0i/20f 32 22 30 20 19 25 233 2 I
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Page 47 and 48: 1+ I5V£/JJiJ-5|T> -TUNEWBOtWfOiAMP
Page 50 and 51: P40I+I6V(TUNE MUX)P40iP40f3ft wMIK
Page 52 and 53: + I5VOSCP40i^Q ^ |PMOPFR£QASFINAL
Page 54 and 55: M+I5VP40/ x|5v301 K|%34^fM0O£WASR4
Page 56 and 57: IU504ft50647C5042Z00|iFMCTBMtZCT2 1
Page 58 and 59: Inpreparation for service, set up t
Page 60 and 61: 4-2 OSCILLATOR B TESTSTEP MODULE CO
Page 62 and 63: 4-S FILTER TEST.STEP'MODULE CONTROL
Page 64 and 65: 4-8 POLY-MOD TEST—A.STEP MODULE C
Page 66 and 67: i4-11 PITCH WHEEL TRIMThis trim rem
Page 68 and 69: A)I4-16 VCO SCALE TRIMBE SURE RECOR
Page 70 and 71: 4-19 FILTER ENVELOPE AMOUNT VCA BAL
Page 72 and 73: 4-21 FINAL VGA BAL1. Switch PRESET
Page 74 and 75: 115-3 PCB 3BT301 E-040L-\:!Oi 0-U45
Page 76 and 77: I ]U374U375U376U377U37SU379U380U381
Page 78 and 79: 1R419SR4199R4200R4201R4202R4203R420
Page 80 and 81: 51» IR44S7/488 R-025R44S9 R-009R44
Page 82 and 83: kL096 E-066098 E-071100 E-078102 E-
Page 84 and 85: IJ310 M-156312 M-157314 M-158316 M-
Page 86 and 87: JJ51S R-161520 R--162522 R-163524 R
Page 88 and 89: FFFFDBKFETFFFILTFINFINEFOAFREQFSKFT
Page 90 and 91: 11 IJSECTION 8THEORY8-0 INTRODUCTIO
Page 92 and 93: 1 1for the 2 to 5-foot range. The c
Page 94 and 95: IiSECTION 9PRCX^RAMMING9-0 INTRODUC
Page 98 and 99: ByteByte 23Switch Bit (7)OSC A PULS
Page 100 and 101: t J IISECTION 10REVISION 3.1 and 3.
Page 102 and 103: I+ I5V+5dI^1-+5V 2'2pF+I6V+5V^^' U3
Page 104 and 105: T&=* PANEL ASSE^^mtYSAfKEYBOARD,'r-
Page 106 and 107: .^^'»_ u jj'/X H"r,P-*tQ( p5^f -^"
Page 108 and 109: 4/J«-5[E> -TUNER57a12wzofwiOi^^^^^
Page 110 and 111: —T8502J/fRSOBWMfrS/IC5045.iiU502i
Page 112 and 113: ^ 1 1 ;4 PINFigure II-OFigure11-TM1
Page 114 and 115: I 111-2 REVISION 3.0 MEMORY TESTRev
Page 116 and 117: Tr1 1-5 WHEEL BALANCE TRIM1. See pa
Page 118 and 119: SECTION 13PROPHET-5 REV 3.3 UPDATET
Page 120 and 121: iFigure 13-1PCB 3 TOP MODIFICATIONT
Page 122 and 123: T 1ttSillniiinMIttltltlltlillll^- ^
Page 124 and 125: i/*5-tft/jj4-y,6-C90H202 >7-CS0H5Q3
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Page 128 and 129: tV t IEPROM1000.3.0V.8.0V.8.1V.8.21
Page 130 and 131: IJmemory interface1000.3.01000.3.11
Page 132 and 133: ittKRAM, non-volatile (NV)1000.3.01
Page 134: 1voltage-current convertervoice ass
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Sequential Circuits Prophet-5 Service Manual - Audiofanzine

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