Sharp MZ-3500 service manual Controls during read, write, seek, and re- calibrate, Media detection

Page 55

M 7.3500

5-7. Precompensate Circuit

Set the counter to 200ms.

(Actually, slightly longer than 200ms.)

K K I T E DATA

(Fig. 2)

PSO	PS1	FM	MFM	Value of LSI 63
0	0	Not changed	Not changed	1101
0	1	-	LATE(125»is)	1100
1	0	-	EARLY(125ja)	1110
1	1	-	-	-

(Table!)

WDATA-

8MHz

CLOCK

EARLY-

NOMAL-

LATE-

(Fig.3)

The precompensate circuit is used to compensate the peak shift before writing.

The FDC sends out the compensation rate to PSO and PS1 and the data bit location is shifted according to this signal. With issuance of WDATA. the value dependent on PSO and PS1 is set in the LS163. (See Table 1.) For instance, when both PSO and PS1 are low, it will set "1101 (D)" to the LS163, counted up by the 8MHz clock, and QB is sent out When it becomes "1110, 1111". When in EARLY (PSO= "H", PS1="L"), the value "1110(E)" will be set to the LS163 so that the output is issued 125ns earier than "not changed". The QB output, however, will be supplied for a period of two clock cycles.

Media is present.

Media is not present.

5-9. Controls during read, write, seek, and re- calibrate

Above operations are all controlled via the FDC. 1) Control during read and write

I

READ (or WRITE)	f	I
command to FDC.	f	I
		TC-»FDC.
		HALT
		(Wait for interrupt) H-">uit staius
		is read by FDC.
DATA<- FDC
DATA-*FDC

2) Control during seek and recalibration

SEEK (or RECALB) command to FDC

I

HALT

(waits for interrupt) Read'result status from FDC.

5-8. Media detection

Insertion of a media on the MFD is detected via the signal

INDEX from the MFD. Since it takes 200ms for the media

to make a full turn, "NO MEDIA" is detected signaltNI)R t T K Y INDEX does not appear within 200ms.

- 60 -

Image 55

Contents Personal Computer Model Z-350 Video TimerBACKUP, INIT, COPY, DEBUG, Killall MemorySFDI/F Refer to the page TIN Circuit DiagramSlot Slot2 LSI, 1C CmosicChange Disp PresetSymbol SdispUser Basic Area RAMBase SystemMZ-1D07 MZ3500 System configuration of Model MS1 = D MSO = 0 L Software Memory ConfigurationTiming of Reset Signal ROM-IPL SD1 System Loading & CP/MFfff Bank SelectMAO ROM SD3 RAM based BasicOperational description BankMain Memory Mapper Block diagram Relation between MMR main memoryThis paragraph discusses main CPU I/O Main CPU and I/O portTable below describes address map Sub CPU and I/O port 0001Main CPU \m MZ3500Coab Memory mapper MMRSP6102R-001 Block diagramTo Reset Address BUSRAS ROW Address Select Line Address Select Signal MZ3500 Memory mapper MMR SP6102R-001 signal descriptionSrdy Pin No RO1B IN/OUTRO2B 1 1 1 1 1 1 FF 14 I N D3 A7 A6 A5A4A3A2AlAO H E X Uhus 1 O1 1 1 1 0 KI1 Dl Do 17 D6 D5 D2 Dl 1 1 1 1 1 0 FE do D4 D3MZ3500 Memory ROMIPL, RAMCOM, S-RAM select circuit CRT SpecificationAsci Summary of video display specificationGraphic dot Dot pitchBlue Dot color designated byKA7 CH ATCH AI +,! AT A r + + G Ascii CG #1 FFFVideo RAM Structure of Vram #07FFA Structure of character Vram When read/write from GDC#0000 8bit Read/write by Z-80 via the GDC 640 x 200 dots display modeFV = 60 Hz 16KO signal switching 640 x 400 bits display mode FH = 20.92 kHz FV = 47.3 HzSetup of GCD master/slave Master/slave setup by combinationGraphic V-RAM Address Crtc block diagramPage Master slice LSI CSP-1 SP6102C 002 signal description » CK CSP-1 Block DiagramCSH HSY2 2BLK2 LSI CSP-2 SP6012C-003 Signal DescriptionCAS OUT CSP 2 Block Diagram3r00 DSP2 OUTGDC Graphic display controller UPD7220 signal description CSR-1MAGE AD15ILC2NK-CLC AT~BTIStructure CG Address Select CircuitCircuit description VsyncBlsc Character Vram select circuitRead/write from the Z-80 to V-RAM Set GDC command codeFifo Empty? Return when all parameters were sentCsrw C 49H -COMMAND Code Write C 23H Command Code Vecte C 6CH Command CodeFollowing manner Dot display program example-1 60HExplanation VECTE. Dot address is structured on the screenP4 88H P5 HH I T E C 23HKind of line solid line Outline Floppy diskTJ ILJ n Ci D ci Ici VnVn n nV nnn7Data MZ3500 MFD interface block diagram 22 «- o Window FDC UPD765UPD765 signal description MFM recording method Trigger motor on of the timer 555 Selects FDDMZ350C Port used in the MFD interface is as followsControl during seek and recalibration Controls during read, write, seek, and re- calibrateMedia detection 3500 Precompensate CircuitPurpose String of data Pulses from the FDD Data window VFO circuitFilter Phase Detector Amplifier Window VFO circuit configurationBQA MFM ModeFM mode timing chart \\\\ Aload Side =3DSC Indicates the byte position From the top of directory 76 iy 7 EH 77 / FFH\128 Track 10 sector1015 Ii PatatB144 6145 B146 B147 39 B148 B149 B150 B151 39 B74 B75Example 7-bits, even parity, 1 stop bit General specificationData transmission format MZS500Start AC controlsOFF KTS MZ3500 Data output control8251 AC RXEN,UTR , T X E N 3SOO128 2009 6.3 256«--N Wl -»8253 OUT 8253DS7 Printer interfacing circuitAA3 DATOutput General description of the parallel interfaceData transfer timing I/O port map DIN Clock circuit SchematicRead Hold Write Hold SETLSB MSB MZ3500 PD1990AC Block diagram» GETE1 J MmmilSFD 1/F 3500S I C GP I/OFD2 SW2 SW1 On on CE332P OFF on MZ1P02 On OFF IO2824 OFF OFFDipswa SEC\f Canbe in either state Functions Block diagramDescription of each block +5V Switching regulatorTiming chart Alarm generation circuitAt rrn Specification of keyboard controlKey Strobe Key search timing2s 2s22 21 Key22.5/-s 132.5Protocol Key to sub CPU Keyboard controller basic flow ALE DBO DB7 GND Keyboard controller signal descriptionXTAL1 XTAL2 Reset INT PINOn OFF Sub-CPU side ProcedureS C I I 00-FF Shared RAMCRT inter face test Abnormal1 5 c * O DR O.7 Abnormal test endingReady O.H ROM-IPL Main CPU Checker Flow Chart 1/2 100 Main CPU Checker Flow Chart M?M7*500 101Keyboard test Keyboard controller ROM testIPL Flow Chart Load Iocs SEEK& Read Jump \ Boot Address SystemSEEK, Read Error Error105 SUB CPU IPL Flow ChartR R R R F1 LJ LJ LJ LJ LJ LJ LJU J l J J L i J L L j l J J L l J L L l LU LU U LJ LlJ LJ U UAIO IwCRoB MZ-35OO Parts Guide LI LED PWB No Parts CodeS C R I P T I O N IE--or Ooss-zw Qcnw MZ-3500Parts Code N T KS C R I P T I O N ConnectorA a N a D MZ-3500NO. Parts Code Parts CodeNEW VH S N 7 4 0 6 NMark Rank Part S C R I P T I O NCoos M2-3500 J9, MZ1K02,1K03,1K04,1K05 Key unitNO. Parts Code SOCLSI RAM LA aD e Tin N a a Parts CodeMZ-3500 Sharp Corporation