This page contains technical informations on the Sega SC3000 computer equipped with the SF7000 extension
It has been done for people who want to extend the capacity of their emulator (SG-1000 only or SC-3000) to support SC-3000 / SF-7000.
I've worked on Darcnes to
make it supporting SC3000 + SF7000. See snapshots at the end of this page, and you
will see that it works (since november 2000) !
INTRODUCTION
The SC3000 is the computer version of the SG1000 including a keyboard and a serial printer interface.
The SF7000 is an extension for the SC3000 including :
HARDWARE
Memory Map
The SF-7000 is equipped with a 64kb RAM and a 8kb ROM for the IPL (Initial
Program Loader).
The memory map for the SF-7000, either on power-on or during execution of system utility program, is as shown in fig (a) where the IPL is ready for its execution.
At the SF-7000 startup, the system programs (e.g. Disk Basic) are loaded onto RAM starting from the address 0, then after the load has completed, the adress 0 thru 3FFF is switched to RAM and the execution is passed to the starting address of a user program.
The interchange between ROM and RAM in the adress range 0 thru 3FFF is handled by the P.P.I. PC6 Signal (SF-7000 Port Map).
Port Map SC-3000
P.P.I. (8255)
| Port Address | Mode | Assignment |
| &hDC
&hDD &hDE &hDF |
PA : Input
PB : Input PC : Output Control register |
Keyboard (input)
Keyboard (input)/printer, cassette Keyboard scan/printer, cassette |
VDP (TMS 9918A)
| Port Address | Assignment |
| &hBE
&hBF |
VDP data register
VDP command register |
PSG (SN 76489)
| Port Address | Assignment |
| &h7F | PSG |
Port Map SF-7000
P.P.I. (8255A)
| Port Address | Mode | Assignment |
| &hE4
&hE5 &hE6 &hE7 |
PA : Input
PB : Input PC : Output Control register |
FDC/printer check
Printer data output (parallel) FDC/printer control |
FDC (765AC)
| Port Address | Assignment |
| &hE0
&hE1 |
Status register
Data register |
USART (8251)
| Port Address | Assignment |
| &hE8
&hE9 |
USARTD (data)
USARTC (command) |
PPI Functional Table
P.P.I. (SC-3000)
| PA0
to PA7 |
Keyboard input |
| PB0
to PB3 PB4 PB5 PB6 PB7 |
Keyboard input /CONT (to the external terminal B-11)
|
| PC0
to PC2 PC3 PC4 PC5 PC6 PC7 |
Keyboard raster (output) N.C.
|
P.P.I. (SF-7000)
| PA0
PA1 PA2 |
FDC INT : INT signal from input from FDC
BUSY from Centronics printer Pin 17 of the FDC ? |
| PB0
PB1 PB2 PB3 PB4 PB5 PB6 PB7 |
Data outputs to Centronics printer |
| PC0
PC1 PC2 PC3 PC4 PC5 PC6 PC7 |
/INUSE signal to FDD
/MOTOR ON signal to FDD TC signal to FDD RESET signal to FDC N.C. N.C. /RON SEL:Switching between IPL ROM and RAM /STROBE to Centronics printer |
DISKS FORMAT
The surface of each disks is divided into 40 tracks numbered from 0
to 39 counting from the outer-most track.
The surface is further divided into 16 equi-angular sectors, and the
cross section of a sector and a track is simply called a "sector". Sectors
are numbered from 1 thru 16 and each sector can contain 256 bytes of data.
Note that a track consists of 16 sectors.
Also a group of 4 sectors is called a cluster which is the unit utilised in file management.
Thus, since one surface of a disk holds 40 tracks each consisting of
16 x 256-byte sectors, the total amount of data recordable on one disk
side is :
256 bytes x 16 sectors x 40 tracks = 163 840 bytes
Since a space must be reserved on each side of one disk for file management purposes, the user available space is diminished by the amound of that space.
The available space is further diminished in disks such as system disk that already contains some system programs (e.g. DISK BASIC).
Disk Structure :
| Track # | Sector # | Contents |
| 0 | 1 | Disk information
IPL in case of a system disk |
| 0 | 2-16 | Reserved |
| 1 - (*1) | 1-16 | System programs area
User's area for non-system disk |
| (*2)-19 | 1-16 | User's area used for storage of programs, etc |
| 20 | 1-12 | Directory (filename storage) |
| 20 | 13-16 | FAT (sector 13 only) |
| 21-39 | 1-16 | User's area (program area) 77 kb |
Sectors 1 thru 12 of track 20 contains the directory and so does 13 thru 16 contain the FAT (File Allocation Table, a table containing location and order of files), each occupying 160 bytes. In fact only sector 13 is utilized for storage of the FAT.
The Disk Capacity :
| Track | Cluster
(for file management) |
Sector
(Unit of I/O) |
Byte |
| / | / | 1 | 256 |
| / | 1 | 4 | 1 024 |
| 1 | 4 | 16 | 4 096 |
| 40 | 160 | 640 | 163 840 |
The Directory :
The directory is contained in sectors 1 thru 12 on track 20.
Example of Track N°20, Sector N°1:
| 4B 41 4B 45 49 2F 44 20 | 2E | 20 20 20 | 28 | 00 | 00 00 |
| (KAKEI/D . ) | |||||
| 00 00 00 00 00 00 00 00 | 00 | 00 00 00 | 00 | 00 | 00 00 |
| ('KILL'ed file) | |||||
| 54 45 4E 53 55 20 20 20 | 2E | 20 20 20 | 42 | 00 | 00 00 |
| (TENSU . ) | |||||
| 53 41 4C 4F 2F 44 20 20 | 2E | 20 20 20 | 45 | 00 | 00 00 |
| (SALO/D .BAS) | |||||
| File Name (8 bytes) | "." | Extension | see * | Attribute | Not Used |
Attributes :
| Value | Meaning |
| 00 | Non-ASCII format [.] |
| 01 | ASCII format [ ] |
| 02 | Hexadecimal data [*] |
| 80 | Non-ASCII read-only |
| 81 | ASCII read-only |
| 82 | Headecimal read-only |
The FAT :
Files are managed under units of clusters the total number of which
is 160 (0 thru 159) on one side of a diskette. The FAT records the usage
of each cluster on the side of the diskette. The FAT is 160-bytes long
and is contained in sector 13 on track 20, the remaining 96 bytes of the
sector being unused.
Meaning of each byte datum in the FAT :
| FAT data | Meaning |
| 0 - 9F | Clusters in use, having succeeding clusters the value is the number of the cluster succeeding to it. |
| C1 - C4 | The last clusters in use, the lower 4-bits indicates the number of sectors the cluster is using |
| FE | Reserved, can't be used for files (IPL, system programs, directory, etc...) |
| FF | Unused clusters |
System Disks :
At system disk startup, the loader first loads the content of the first
sector on truck 0 into memory in the adress range FF00 thru FFFF, then
checks the first 4 bytes starting from adress FF00. It then displays onto
the screen the filename immediately following the first 4 bytes, and jumps
to the IPL program from the adress FF20.
Thus if you want to create a system disk, the first thing you have to
do is to save the system disk id code, the filename, and the IPL program
onto the first sector on truck 0 of the disk.
| Address | Data (hex) | Data (ascii) | Contents |
| FF00
FF01 FF02 FF03 |
53
59 53 3A |
S
Y S : |
System disk identification code |
| FF04
FF1F |
20
64 69 73 6B 20 42 41 53 49 43 00 ... |
d i s k B
|
File name displayed on screen during boot |
IPL Program on disk (referencial example)
|
LOOP
EXIT
|
ORG
CALL JP LD LD LD CALL
LD
|
OFF20H
8 C,0 DE,0 BC,0101h HL,1009h 10h
A,3
|
; track 0 ; error then boot ; load start adress ; start sector=1 track=1 ;end sector=10h track=9 ; Motor off ; select
|
DISK BASIC COMMANDS, STATEMENTS AND FUNCTIONS
[ ] means an optional parameter
In bold are the minimum to known if you want to run a program ;-)
Commands List
| Command name | Function |
| AUTO | Automatically generates line numbers |
| BOOT | Re-loads system programs from disk |
| CLOAD ["file"] | Loads programs from cassette |
| COMLOAD | Receives programs via RS-232C interface |
| COMSAVE | Sends programs via RS-232C interface |
| CONT | Resumes interruptes programs |
| CSAVE "file" | Saves programs onto cassettes |
| DELETE | Deletes parts of programs |
| FILES | Displays names of files on disk |
| LFILES | Outputs to printer names of files on disk |
| LIST [-][LineNumber][-][LineNumber] | Displays programs onto the screen |
| LLIST [-][LineNumber][-][LineNumber] | Outputs programs to printer |
| LOAD "file" | Loads programs from disk |
| MAXFILE n | Declares number of simultaneously openables files |
| MERGE "file" | Merges programs on disk with program in memory |
| NEW | Deletes/resets programs and variables in memory |
| NEWON StartAddress | Sets starting address for program area |
| RENUM | Re-sequence line numbers of programs |
| RUN ["file" or LineNumber] | [Load] / Begin execution of programs [at the Line given] |
| SAVE "file" | Saves programs onto disk |
| UTILITY | Enters disk utility program (at the prompt :
F : to format a disk, C : to copy a disk, B : to boot) |
| VERIFY | Compares program in memory with that saved on cassette |
Statements List
| Statement name | Function |
| BCIRCLE | Deletes by circle |
| BEEP [n] | Beeps |
| BLINE | Deletes by line |
| CALL Address | Calls machine language subroutines |
| CIRCLE | Draws circles |
| CLOADM "file"[,StartAddress] | Loads machine language programs from cassette |
| CLOSE [n,...] | Closes specified files |
| CLS | Clears screen |
| COLOR | Specifies color |
| COMSET lgt,parity | Used for RS232C interface to specify data length (5,6,7,8), sets/resets
parity bit (E,O,N)
By default : 8 bits, Even parity |
| CONSOLE | Sets scroll limit for the screen, click sound, upper/lower case distinction, and select printer |
| CSAVEM "file",StartAddress,EndAddress | Saves machine language programs onto cassette |
| CURSOR | Sets cursor position on the screen |
| DATA | Specifies data to be read by the READ statement |
| DEF FN | Defines user functions |
| DIM | Declare arrays |
| DSKI$ Track,Sector;Var,Start,End | Does direct read of a sector from disk |
| DSKO$ Track,Sector;Var,Start,End | Does direct write of a sector to disk |
| END | Terminates program execution |
| ERASE | Clears declared arrays |
| FOR TO [STEP] - NEXT | Repeat lines between FOR and NEXT - STEP means increment to FOR |
| GET #n,fic;Var,Start,End | Read into variable data in random files |
| GOSUB LineNumber-
RETURN |
Jumps to line specified by line number
Returns from subroutine |
| GOTO LineNumber | Jumps to line specified by line number |
| HCOPY | Outputs to printer current screen image |
| IF THEN | Conditionnally jumps to/executes statements |
| INPUT | Input value or character string from keyboard |
| INPUT #n,Var | Input value or character string from indicated sequential file or from RS232C interface (n = file(1 to 8) or RS232C (0) ) |
| KILL "file" | Erase files from disk |
| LET | Assigns value to variable (omittable) |
| LIMIT EndAddress | Sets end address for BASIC program area |
| LINE | Draws line |
| LOADM "file"[,StartAddress] | Loads machine language programs into specified memory area |
| LPRINT or L? | Ouput to printer value or character string
Characters and symbols must be enclosed in " " |
| MAG | Set sprite mode/width |
| NAME "OldFile" AS "NewFile" | Change name of programs on disk |
| ON GOSUB -
RETURN |
Conditionnally jumps to subroutine indicated by line number
Returns from subroutine |
| ON GOTO | Conditionnally jumps to line indicated by line number |
| OPEN "file" FOR "mode" AS#n | Opens disk files (mode="INPUT" or "OUTPUT" or "APPEND") |
| OUT | Outputs data to output board |
| PAINT | Paints specified region |
| PATTERN t#x,"" | Sets character (C#) or sprite (S#) pattern |
| POKE | Write data in memory |
| POSITION | Sets coordinate for graphics screen |
| PRESET | Deletes by points |
| PRINT or ? | Display value or string onto screen
Characters and symbols must be enclosed in " " |
| PRINT #n,Var | Write value or character string to specified sequential or RS-232C interface (n = file(1 to 8) or RS232C (0) ) |
| PSET | Draws point |
| PUT #n,fic;Var,Start,End | Write value of expression to random file |
| READ | Reads data specified in DATA statement |
| REM | Marks comment |
| RESTORE | Specifies DATA statement to be read by READ statement |
| SAVEM "file",StartAddress,EndAddress | Save machine language program onto disk |
| SCREEN | Declare text window, graphics window |
| SET "file","P" | Sets file mode ("P" for read-only) |
| SOUND | Generates sound |
| SPRITE | Specifies sprite |
| STOP | Interrupt program execution |
| VERIFYM "file"[,StartAddress] | Compares machine language program saved on cassette with program in memory |
| VPOKE | Write data into VRAM |
Functions List
| Function name | Function |
| ABS(x) | Gives absolute value of x |
| ACS(x) | Gives inverse cosine of x in radian |
| ASC(S) | Converts character S into equivalent ASCII code |
| ASN(x) | Gives inverse sine of x in radian |
| ATN(x) | Gives inverse tangent of x in radian |
| CHR$(x) | Converts ASCII code into character or control code |
| COS(x) | Gives cosine of x |
| DEG(x) | Converts radian to degree |
| DSKF | Used to check free space on disk |
| EOF(#x) | Used to check whether sequential file is read to the end of file, -1: yes, 0: no |
| EXP(x) | Gives e to the power of x |
| FRE | Used to check free space in user memory area |
| HEX$(x) | Converts x into hexadecimal numeric character string |
| INKEY$ | Gives code of the key being pushed |
| INP(x) | Gives input value of input board x |
| INPUT$(x,#y) | Set character string x-characters long from sequential file #y |
| INT(x) | Gives greatest integer not greater than x |
| LEFT$(S,x) | Gives substring x-characters long from the beginning of character string S |
| LEN(S) | Gives length of character string S |
| LGT(x) | Gives common logarithm of x |
| LOC(n) | Gives logical offset in file |
| LOF(n) | Give file size |
| LOG(x) | Gives natural logarithm of x |
| LTW(x) | Gives logarithm of x to the base 2 |
| MID$(S,x[,y]) | Gives substring starting from x-th character, y-characters long, to the end if y omitted |
| PEEK(x) | Gives contents of memory at address x |
| PI | Gives ratio of circumference of circle to diameter (3.1415926536) |
| RAD(x) | Gives equivalent angle in radian of x in degree |
| RIGHT$(S,x) | Gives substring from x-th character counting from right to the end of string S |
| RND(x) | Generates random number |
| SGN(x) | Gives numerical sign of x |
| SIN(x) | Gives sine of x in radian |
| SPC(x) | Used in PRINT statement, print x consecutive spaces |
| SQR(x) | Gives square root of x |
| STICK(n) | Detects input direction for joystick n |
| STR$(x) | Converts x into equivalent character string |
| STRIG(n) | Detects condition of push-button of joystick n |
| TAB(x) | Used in PRINT statement, sets the start position to be x-th column from left |
| TAN(x) | Gives tangent of x in radian |
| TIME$ | Used to see inner clock |
| VAL(S) | Converts numeric character string S into equivalent number |
| VPEEK(x) | Gives content of VRAM at address x |
DOWNLOAD
Downloading the IPL ROM of 8kb.
Downloading the SEGA BASIC SYSTEM
DISK.
Downloading KAMIKAZE IMAGE DISK (Loriciels
game)- Fixed for sf7000 (Original on K7)
Downloading CROCKY IMAGE DISK (Loriciels
game) - Does not work, needs to be fixed. (Original on K7).
Downloading POSEIDON WARS/SPACE
PANIC DISK (Z80 games done by myself).
Downloading Z80 STUFFS INCLUDING THE MONITOR DESSASSEMBLER (Loriciels - original on K7).
To run The Monitor/Desassembler type : LOADM "MO-D808.HEX" then CALL &HD808
Downloading TOOL TO DRAW PICTURES + DATA PICTURES (done by myself).
Downloading DATA PICTURES (done by myself and others).
Downloading Some progs from the book '102 Progs For Yeno'.
Downloading Some progs form the book 'Super Jeux Yeno'.
Downloading Games_1.
Downloading Games_2.
Downloading Board games.
Downloading Olympiades.
Downloading Educational games.
Downloading Graphics.
Downloading Musics.
Downloading Electricity utility.
HOW TO TRANSFER SF7000 DISKS
I used a basic program on the SC3000 to transfer disk on the serial port. On the other side (Amiga) I obtain an ascii file with a terminal utility. This one must be converted to an image disk before use with an emulator.
Downloading the Basic program to transfer disk on serial port of the sf7000.
Downloading the C source to convert ascii file transfered to a bin file (image of the disk).
Note: You will have to type the basic program on the sc3000. You will have to compile the c source to obtain the exe.
SOME SNAPSOTS WITH THE VERSION OF DARCNES I'VE MODIFIED
Sega basic demos
Kamikaze
Poseidon wars
Space panic
LINKS
