Cromemco Z-80A Instruction Manual Download Page 1

Summary of Contents for Z-80A

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Page 2: ...Part No 023 0012 CROMEMCO ZPU Instruction Manual CROMEMCO INC 280 Bernardo Avenue Mountain View CA 94040 Copyright 1978 September 1978 ...

Page 3: ...OPERATING INSTRUCTIONS 3 2 1 POWER ON JUMP 3 2 2 Z 80A CLOCK FREQUENCY SELECTION 6 2 3 WAIT STATE SELECTION 7 2 4 ADDRESS MIRROR SELECTION 9 2 5 REFRESH ENABLE 9 2 6 ALTAIR OR IMSAI INSTALLATION 10 Section 3 THE S 100 BUS 11 Section 4 ASSEMBLY INSTRUCTIONS 19 ZPU PARTS LIST 23 ...

Page 4: ...us features Read Section 2 OPERATING INSTRUCTIONS before inserting the ZPU into your system S 100 bus TECHNICAL SPECIFICATIONS Z 80A Microprocessor Card PROCESSOR 4 MHz version of the Z 80 CLOCK RATE 2 4 MHz switch selectable INSTRUCTION SET 158 instructions including the 78 instructions of the 8080 POWER ON JUMP jumper wire enabled POWER ON JUMP LOCATIONS 16 locations switch selectable WAIT STATE...

Page 5: ...rs Power On Jump capability an on board wait state generator optional independent selection of Ml wait states address mirroring circuitry and several other features discussed in this section 2 1 POWER ON JUMP The ZPU Power On Jump circuitry allows the board to be used in an S 100 bus system wi thout front panel controls e g Cromemco I s Z 2 Z 2D and SYSTEM THREE When system power is turned ON the ...

Page 6: ...H 1 1 1 1 F000H Note the Jump Address switch determines the four highest order bits in the jump address with all other address bits set to logic 0 EXAMPLE 1 Suppose you have a Cromemco Z 2D System which comes standard with a 4FDC card and RDOS Resident Disk Operating System in PROM memory This program which resides at C000 C3FFH provides a convenient way to start up a system To effect an automatic...

Page 7: ...he Jump Address switch to EIOIOIOH as shown below JUMP ADDRESS 1 0 zo c J 15 c JN 14 c Jw 13 c c 12 Your ZPU is factory shipped with the Power On Jump fea ture enabled To disable the function resulting in an automatic jump to address IOIOIOIOH only on a Power On Clear or RESET carefully cut the foil trace connecting two points on the board labeled JUMP ENABLE I f you r comput e r s y s t em has RE...

Page 8: ... pressing the STOP switch then raising the RESET switch The number C3H should appear in the DATA display This is the op code of the hardware jump instruction Now press the EXAMINE NEXT switch all 0 s will appear in the DATA display indicating the low order 8 bits of the jump address Press the EXAMINE NEXT switch again the high order 8 bits of the jump address will now appear in the DATA display Th...

Page 9: ...ZPU allows two types of wait state insertion The first inserts from 0 to 3 wait state cycles 1 cycle 250 nsec at 4 MHz 500 nsec at 2 MHz during every machine cycle the second type inserts either one or no additional wait states during an instruction fetch cycle only referred to as an Ml cycle in the Zilog literature where the timing requirements are the tightest If you are using Cromemco memory bo...

Page 10: ...sec whi le an Ml wai t state slows the required memory access time an additional 110 nsec approx The corresponding figures for 2 MHz operation are no wait states for 500 nsec memory boards 500 nsec per W wait state added and an additional 235 nsec approx for an Ml wait state You may find these figures to be somewhat conservative in actual practice To get the maximum performance from your memory yo...

Page 11: ...0 systems The address mirror circuitry is enabled by the short run of foil between pads labeled AM and ON between IC7 and IC8 on the board If you wish to disable this circuitry carefully cut the existing foil trace and in its place connect pads AM and OFF with a jumper wire 2 5 REFRESH ENABLE Certain types of dynamic memory boards require that the ref resh add ress suppl i ed by the Z 80A be mi r ...

Page 12: ...R 8800 or 8800A computer a DIP plug must be installed in place of the Molex connector on the front panel cord When wiring the connector note that the data lines are not arranged sequentially on the ALTAIR connector as they are on the ZPU connector refer to the figure below for wiring information ZPU SOCKET Jl IIIIIIII D7 D6 D5 D4 D3 D2 Dl D0 10 ALTAIR MOLEX CONNECTOR o 0 0 0 0 0 0 0 D3 D2 Dl D0 D4...

Page 13: ...named the IIS 100 11 bus by Dr Roger Melen of Cromemco Inc in August of 1976 The S 100 or IIStandard 100 11 bus is now widely regarded as the most used busing standard ever developed in the computer industry Physically the S 100 bus is realized as a set of 100 contact edge connectors mounted to a common mother board and wired in parallel The modules that plug into the edge connectors of the S 100 ...

Page 14: ...EADY 28 pINTE 53 SSW DISABLE 78 pDBIN 4 UNDEFINED 29 A5 54 EXT CLEAR 79 A0 5 30 A4 55 UNDEFINED 80 Al 6 3I A3 56 8I A2 7 32 A15 57 82 A6 8 33 A12 58 83 A7 9 34 A9 59 84 A8 10 35 DOl 60 85 A13 II 36 D00 6I 86 A14 12 NMI 37 A10 62 87 All 13 UNDEFINED 38 D04 63 88 D02 14 39 D05 64 89 D03 15 40 D06 65 MEM REQUEST 90 D07 16 4I DI2 66 REFRESH 9I DI4 17 42 DI3 67 UNDEFINED 92 DI5 18 STATUS DISAB 43 DI7 6...

Page 15: ...l regulator IC s Distributed power supply regulation has several advantages over a single centrally regulated supply Each card is indi vidually protected from vol tage overload Faul ty regulation in one master supply cannot destroy the entire computer system The heat produced by voltage regulation is thermally distributed through a larger physical volume Voltage drops along the bus do not influenc...

Page 16: ...l PIN 80 A9 PIN 34 A2 PIN 81 A10 PIN 37 A3 PIN 31 All PIN 87 A4 PIN 30 A12 PIN 33 AS PIN 29 A13 PIN 85 A6 PIN 82 A14 PIN 86 A7 PIN 83 A15 PIN 32 There are 16 address lines on the S 100 bus allowing the direct addressing of 65 536 words of memory space Tri state TTL drivers are used to drive the address bus One S 100 bus cont rol 1 i ne ADDRESS DI SABLE can be used to disable the address drivers to...

Page 17: ...put bus is called the DO bus The S 100 provides for one control line to disable the DO bus DO DISABLE for DMA operations S 100 CLOCK AND CONTROL SIGNALS EXT READY PIN 3 SSW DISABLE PIN 53 NMI PIN 12 EXT CLEAR PIN 54 STATUS DISAB PIN 18 MEM REQ PIN 65 CONTROL DISAB PIN 19 REFRESH PIN 66 UNPROTECT PIN 20 MEM WRITE PIN 68 SINGLE STEP PIN 21 PROTECT STATUS PIN 69 ADDR DISAB PIN 22 PROTECT PIN 70 DO DI...

Page 18: ...the 8080 microprocessor are prefixed with a lower case p Thus pHLDA pWAIT pINTE pREADY pHOLD pINT pRESET pSYNC pWR and pDBIN serve the same function as the corresponding control signals for the 8080 microprocessor Similarly S 100 bus signals prefixed with an s are functionally equivalent to the corresponding outputs of the 8080 status latch These signals include sMl sOUT sINP sMEMR sHLTA sINTA sWO...

Page 19: ...efined lines are used primarily in S 100 systems wi th an operator s front panel A front panel swi tch can be used to protect RAM or PROM memory from accidental memory write operations by issuing a PROTECT pin 70 signal to the bus The memory can be unprotected by the UNPROTECT pin 20 signal and the current PROTECTED or UNPROTECTED status of any memory can be determined from the PROTECT STATUS pi n...

Page 20: ...SW DISABLE pin 53 is used to disable the DI bus during sense switch inputs EXTERNAL CLEAR pin 54 is activated by an auxillary front panel switch but it is assigned to no specific function Finally there is the POWER ON CLEAR signal that remains at logic 0 when power is first turned on and then transitions to logic 1 approximately 100 milliseconds later to indicate tha t po we r is on and the power ...

Page 21: ...r and a fine tipped low wattage 25 W or less soldering iron The printed legend on the component side shows the exact position and orientation of each component instruction step when completed Check off each Solder in position the 1 4 watt 5 carbon film resistors Rl R2 R3 R4 R5 R6 R7 R8 R9 R10 Rll R12 R13 lK lK 180 180 270 270 10K 390 330 330 lK 100 180 brown black red brown black red brown grey br...

Page 22: ...all SIP res i s tor netw0 r ks RN 3 RN 4 and RN 5 The arrow tips printed on the circuit board point to pin 1 align arrows with numerals 1 printed on the RN packages Install Ql a 2N3904 transistor with the flat side fac ing the top of the board Ins ta 11 the hea ts i nk and vo 1tage regula to r ICs IC I and IC2 in the upper left hand corner of the board Make sure the regulator legs do not make cont...

Page 23: ... in place Install the four posi tion Jump Address swi tch on the right side of the board The arrow on the swi tch package indicating the ON position should point to the right Install all ICs and resistor networks in their sockets see Note below The arrow tips printed on the circuit board point to pin 1 see figure below PIN 1 r r _ After inserting the ICs and RNs verify that they are all oriented i...

Page 24: ...IC socket span Then rock the IC into its socket wi th a gentle end to end pressure Visually inspect the legs after insertion by looking beneath the device This completes the construction of the Cromemco Z 80 CPU board Carefully inspect your work before proceeding Take particular care to see that there are no inadvertent solder bridges between pads and adjacent foil areas 22 ...

Page 25: ... 74157 010 0009 R8 390 001 0013 IC5 Z 80A 011 0010 R9 330 001 0012 IC6 74LS04 010 0066 R10 330 001 0012 IC7 74LS10 010 0063 Rll lK 001 0018 IC8 7400 010 0000 R12 100 001 0007 IC9 7474 010 0019 R13 180 001 0009 lC10 7404 010 0030 R15 330 001 0012 ICll 74367 010 0080 R15 330 001 0012 IC12 74367 010 0080 R16 330 001 0012 IC13 74367 010 0080 R17 180 001 0009 IC14 74367 010 0080 R18 lK 001 0018 IC15 74...

Page 26: ... 4 6 32 NUTS 4 18 WIRE SOCKET 40 PIN 22 S0CKETS 14 PIN 21 S0CKETS 16 PIN ZPU PC BOARD Software 009 0001 026 0001 013 0000 013 0001 021 0017 015 0000 015 0013 019 0012 017 0006 017 0001 017 0002 CROMEMCO Z 80 MONITOR PAPER TAPE Documentation Z 80 MONITOR MANUAL ZPU INSTRUCTION MANUAL Z 80A CPU TECHNICAL MANUAL 24 ...

Page 27: ... period it will be repaired provided that it is returned to Cromemco for a fixed service fee We reserve the right to refuse to repa i r any product tha tin our opi ni on has been subject to abnormal electrical or mechanical abuse The service fee is currently 70 00 and is subject to change Your assembled ZPU kit will be repaired provided that it is returned to Cromemco for a fixed service fee We re...

Page 28: ...ZPU INSTRUCTION MANUAL merchandise The service fee is currently 70 and is sUbject to change 26 ...

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