MiSTer MultiComp

Port of Grant Searle's MultiComp to the MiSTer.

Ported by Cyril Venditti and Fred VanEijk.

Updated by S0urceror to use MiSTer image files, use all 4 machine types and have the MiSTer UART connected to serial interface 2 of the core. The latter allows to use the core remotely.

Using the MiSTer Serial Terminal/Console

Connection Methods

1. USB: Connect the console port from the MiSTer FPGA to your computer using a USB cable.

2. Network: Use SSH to connect to the MiSTer FPGA if you have a Wireless or Ethernet connection.

3. USB/Serial cable: For more information see the Serial Port section of the Altair8800_MiSTer repository: https://github.com/MiSTer-devel/Altair8800_MiSTer

Setting Up the Connection

For UART/Serial with PuTTY

• Connect at 115200 baud, 8 bits, no parity to the COM port.

USB to serial cable connection

User Port - extra USB 3.1A style connector on MiSTer

USB	P7	Name	PIN	Mister	emu wire
1	+5V	+5V
2	2	TX	SDA	AH9	USER_IO[1]
3	1	RX	SCL	AG11	USER_IO[0]
4	GND	GND
5	8	DSR	IO10	AF15	USER_IO[5]
6	7	DTR	IO11	AG16	USER_IO[4]
7	6	CTS	IO12	AH11	USER_IO[3]
8	5	RTS	IO13	AH12	USER_IO[2]
9	10	IO6	IO8	AF17	USER_IO[6]
10	Shield	Shield

FT232 USB to serial cable

wire	name	mister usb IO port
Red	5V	N/C
Black	GND	GND
White	RXD	2
Green	TXD	3
Yellow	RTS	7
Blue	CTS	8

For SSH with PuTTY

• Connect to the ip address of your MiSTer fpga.

Linux command line to establish the connection to the core

1. Identify the UART device:

   • Usually mapped to /dev/ttyS1 or /dev/ttyUSB0

   • Use this command to help identify the correct device:

     dmesg | grep tty

2. Access the serial terminal:

   • Use screen or minicom

   • Example command with screen:

     screen /dev/ttyS1 115200

   • Replace /dev/ttyS1 with the correct device identifier

   • Change 115200 to the appropriate baud rate if different

3. Enable Flow Control:

   • Use stty

     stty -F /dev/ttyS1 crtscts

   • Replace /dev/ttyS1 with the correct device identifier

   • This is done before the screen command

Additional Information

For more details on console connection, refer to the official MiSTer documentation: MiSTer Console Connection Guide

The MiSTer OSD allows the access to four machines

Z80 CP/M

You can now use both an external SDCard in the secondary slot and/or select the image file within MiSTer. Whatever you like.

Formatting the SD Card and Installing CP/M

Note this procedure has to be performed from a tty terminal as descibed above.

Formatting the Drive

1. Load the Intel-HEX dump of the FORMAT program into memory by copying the contents of FORM128.HEX (for 128MB SD card utilization) into the terminal window.
2. The FORMAT program will reside at memory address $5000 when loaded. To start the formatting process, execute the program by typing G5000 and pressing ENTER.
3. You will see the following message:

CP/M Formatter by G. Searle 2012

4. After a few seconds, the formatting process will display:

ABCDEFGHIJKLMNOP
Formatting complete

Each drive is 8MB, so a 128MB SD card will have drives labeled A: to P:.

Installing CP/M

CP/M is installed on the first track of the disk. When booted, the first track is read into memory and executed. To install CP/M, follow these steps:

1. Load the Intel-HEX dump of CP/M by copying the contents of CPM22.HEX into the terminal window (this takes about 10 seconds).
2. Load the Intel-HEX dump of the CBIOS by copying the contents of CBIOS128.HEX (for 128MB total drive space) into the terminal window (this takes about 3 seconds).
3. Load the Intel-HEX dump of PUTSYS by copying the contents of PUTSYS.HEX into the terminal window.

The PUTSYS program also resides at memory address $5000. To transfer CP/M and CBIOS to the disk, execute PUTSYS by typing G5000 and pressing ENTER. You will see:

CP/M System Transfer by G. Searle 2012
System transfer complete

At this point, CP/M is installed and ready for boot. You can now proceed with installing applications.

Boot CP/M from image file

Note that currently the DOWNLOAD.COM program is not working reliably (we hope to fix this in the future). To get around the issues with DOWNLOAD.COM we have added the cpm image file and some Python based utilities, thus being able to get a working and custamizable CP/M sytem up and running.

In the CPM-sd-image directory, you will find a zip file that contains a cmp.img file that can be copied to the /media/fat/games/MultipComp directory. This file can be used to boot CP/M without the SD card. It contains the structure for disks A thru P with A having the DOWNLOAD program and other utilities available. Use this as a strating point to place CP/M applications on the image. See the Installing Applications section at http://searle.x10host.com/Multicomp/cpm/fpgaCPM.html#InstallingCPM.

Note the process for this is mostly described in PART 2 - Using the Windows packager program. The packager program is in windowsApp. Again, this process requires the use of the tty terminal not the console, as you will be pasting the file data into the terminal.

We have also added a zip file in the CPM-sd-image directory with a set of application pre installed. See cpm-apps.zip. This file can also be copied to the /media/fat/games/MultipComp directory and mounted. It contains 5 drives A,C,D,E, and F where A still only has the DOWNLOAD program and the other drives contain the following. The cpm.zip file contains just the basic utilities described in the CPM-sd-image directory.

C:	D:	E:	F:
0_FILES.TXT	0_GAMES	0_OLDUTILS	0_NEWUTILS
1_BDS_TINY_C	1_MUMATHSIMP	1_F80M80BASIC	1_ROMS
2_APL	2_CROSSTALK	2_AZTEC_C_106D	2_ZSYSTEM
3_JANUS_ADA15	3_QTERM43	3_TPASCAL3	3_MICROPRO
4_MS_COBOL	4_CLINK	4_DXFORTH401	4_MULTIPLAN
5_PILOT	5_SUPERSFTUTIL	5_PLI14	5_DBASEII
6_SYSLIB	6_RCPM	6_ALGOLM	6_DWG_APPS
7_BBC BASIC	7_DDTZ SOURCES	7_SUPERCALC	8_MICROSHELL

Note the use of user numbers here i.e. 0_, 1_ etc..
(Not all the applications were tested to run, so you are on your own)

The applications were obtained from the Obsolescence Guaranteed site.

Included in the CPM-sd-image directory are also some python scripts to initialize/build the image for the CP/M disks. Along with a script in the transient packages directory that can extract the .COM files from the package (note this was used to provide some content to build the cpm.img file provided in CPM-sd-image directory).

To use the Python scripts we recommend using Visual Studio Code and opening the MultiComp_MiSTer directory as its project location. Them just run the Python scripts from within Visual Studio Code.

Other useful links.

For convenience you can use the Multicomp FPGA - CP/M Demo Disk from Obsolescence Guaranteed: http://obsolescence.wixsite.com/obsolescence/multicomp-fpga-cpm-demo-disk

After you have flashed the CP/M Demo Disk to the SD Card you will have to use the secondary SD Card on the MiSTer on the I/O Board: https://github.com/MiSTer-devel/Wiki_MiSTer/wiki/IO-Board

Using CP/M - from Grant Searle website: http://searle.x10host.com/Multicomp/cpm/fpgaCPM.html

DeRamp - This website focuses on early personal computers from the mid 70s into the early 80s. Here you'll find resources for restoring and maintaining many of the great computers and peripherals from this era, in addition it has a Downloads section where you can find the bits for many applications. https://deramp.com/

Z80 Basic

SGN, INT, ABS ,USR, FRE, INP, POS, SQR, RND ,LOG, EXP, COS, SIN, TAN, ATN, PEEK ,DEEK ,LEN, STR$, VAL ,ASC, CHR$ ,LEFT$, RIGHT$, MID$, END, FOR, NEXT, DATA, INPUT, DIM, READ, LET, GOTO, RUN, IF, RESTORE, GOSUB, RETURN, REM, STOP, OUT, ON, NULL, WAIT, DEF, POKE, DOKE, LINES, CLS, WIDTH, MONITOR, PRINT, CONT, LIST, CLEAR, NEW, TAB, TO, FN, SPC, THEN, NOT, STEP, +, -, *, /, ^, AND, OR, >, <, =

PLUS additional implementations here (making it version 4.7b):

HEX$(nn) - convert a SIGNED integer (-32768 to +32767) to a string containing the hex value

BIN$(nn) - convert a SIGNED integer (-32768 to +32767) to a string containing the binary value

&Hnn - interpret the value after the &H as a HEX value (signed 16 bit)

&Bnn - interpret the value after the &B as a BINARY value (signed 16 bit)

6502 Basic - No SD card support (No CSAVE/CLOAD)

END, FOR, NEXT, DATA, INPUT, DIM, READ, LET, GOTO, RUN, IF, RESTORE, GOSUB, RETURN, REM, STOP, ON, NULL, WAIT, DEF, POKE, PRINT, CONT, LIST, CLEAR, NEW, TAB(, TO, FN, SPC(, THEN, NOT, STEP, SGN, INT, ABS, USR, FRE, POS, SQR, RND, LOG, EXP, COS, SIN, TAN, ATN, PEEK, LEN, STR$, VAL, ASC, CHR$, LEFT$, RIGHT$, MID$, +, -, *, /, ^, AND, OR, >, +, <

6809 Basic - No SD card support(No CSAVE/CLOAD)

FOR, GO, REM, ELSE, IF, DATA, PRINT, ON GOSUB, ON GOTO, INPUT, LINE INPUT, END, NEXT, DIM, READ, RUN, RESTORE, RETURN, STOP, POKE, CONT, LIST, CLEAR, NEW, EXEC, TAB, TO, SUB, THEN, NOT, STEP, +, -, *, /, ^, AND, OR, >, =, <, DEL, DEF, LET, RENUM, FN, &, &H, TRON, TROFF, EDIT, SGN, INT, ABS, USR, RND, SIN, PEEK, LEN, STR$, VAL, ASC, CHR$, LEFT$, RIGHT$, MID$, INKEY$, MEM, ATN, COS, TAN, EXP, FIX, LOG, SQR, HEX$, VARPTR, INSTR, STRING$, MID$ (MODIFICATION), POS

http://searle.x10host.com/Multicomp/#BASICKeywords

MultiComp OSD Configuration

This section describes the On-Screen Display menu configuration for the MultiComp system, providing control over CPU selection, storage, and communication parameters.

Menu Structure

System Control

• Mount *.IMG: Provide the image in the games/Multicomp directory if no image is specified it will attempt to use the secondary SD card
• Reset after Mount: Configures system behavior after mounting storage - Options: No, Yes
• Reset: System reset function

CPU and ROM Configuration

• CPU-ROM Selection:
• Z80 with CP/M
• Z80 with BASIC
• 6502 with BASIC
• 6809 with BASIC

Communication Settings

• Baud Rate:
• 115200
• 38400
• 19200
• 9600
• 4800
• 2400
• Serial Port:
• Console Port - use the MiSTer console port
• User IO Port - use the MiSTer user I/O USB 3.1 port
• Flow Control:
• None - no hardware flow control
• RTS/CTS - enable hardware flow control using RTS/CTS signals

Additional Information

The OSD includes version information and build date tracking. This configuration interface provides comprehensive control over the MultiComp's core functionality, allowing users to switch between different CPU architectures, operating systems, and I/O configurations.

The menu system is designed for straightforward navigation and configuration of the MultiComp's essential features, making it accessible for both basic setup and advanced customization needs.

Troubleshooting

Serial Communication Issues

• Only the Z80 supports the external uart at this time
• If no response when typing:
  • Verify correct baud rate is selected
  • Check that the correct serial port is selected (Console vs User IO)
  • Try enabling/disabling flow control
  • For User IO port, verify cable connections match pinout documentation

Storage Issues

• If unable to access CP/M:
• Verify Secondary SD card is properly formatted or an image is selected in the OSD
• Try toggling "Reset after Mount" option
• Once either the secondary SD card is selected or the Image file is selected a complete MiSTer re-start is required to change the selection i.e. it can not be changed with a reset of the core.

System Stability

• 6809 Basic had known reset issues (inherited from original design) the core was actually being reset but only a warm reset, now it supports a cold or warm reset with a prompt
• If system becomes unresponsive:
  • Use OSD Reset function
  • Try power cycling the MiSTer
  • Verify correct CPU-ROM selection for your intended use

Known Limitations

• If the DOWNLOAD.COM program has reliability issues in CP/M use a slower baud rate, we have had some sucess at 2400 and 9600 baud, 115200 baud seems to consistantly drop characters even with flow control enabled
• 6502 and 6809 Basic variants do not support SD card operations (no CSAVE/CLOAD)\

License

Software and VHDL project download link

By downloading these files you must agree to the following: The original copyright owners of ROM contents are respectfully acknowledged. Use of the contents of any file within your own projects is permitted freely, but any publishing of material containing whole or part of any file distributed here, or derived from the work that I have done here will contain an acknowledgment back to myself, Grant Searle, and a link back to this page. Any file published or distributed that contains all or part of any file arom this page must be made available free of charge.

Original Author

Grant Searle

URL

Grant's MULTICOMP pick and mix computer

MiSTer MultiComp BASIC Keywords Reference

Keywords by Category

Mathematical Functions

Keyword	Z80	6502	6809	Description	Usage Example
ABS	✓	✓	✓	Returns absolute value	X = ABS(-5)
ATN	✓	✓	✓	Returns arctangent	A = ATN(1)
COS	✓	✓	✓	Returns cosine	C = COS(3.14159/2)
EXP	✓	✓	✓	Returns e raised to power	E = EXP(2)
FIX	-	-	✓	Truncates decimal portion	F = FIX(3.7)
INT	✓	✓	✓	Returns integer portion	I = INT(5.7)
LOG	✓	✓	✓	Returns natural logarithm	L = LOG(100)
SGN	✓	✓	✓	Returns sign of number (-1,0,1)	S = SGN(-42)
SIN	✓	✓	✓	Returns sine	S = SIN(3.14159/2)
SQR	✓	✓	✓	Returns square root	R = SQR(16)
TAN	✓	✓	✓	Returns tangent	T = TAN(0.785)

String Functions

Keyword	Z80	6502	6809	Description	Usage Example
ASC	✓	✓	✓	Returns ASCII value of character	A = ASC("A")
CHR$	✓	✓	✓	Returns character for ASCII value	C$ = CHR$(65)
INSTR	-	-	✓	Searches for substring	I = INSTR(A$, "FIND")
LEFT$	✓	✓	✓	Returns leftmost characters	L$ = LEFT$("HELLO", 2)
LEN	✓	✓	✓	Returns string length	L = LEN("TEST")
MID$	✓	✓	✓	Returns substring	M$ = MID$("HELLO", 2, 2)
RIGHT$	✓	✓	✓	Returns rightmost characters	R$ = RIGHT$("WORLD", 3)
STR$	✓	✓	✓	Converts number to string	S$ = STR$(123)
STRING$	-	-	✓	Creates string of repeated characters	S$ = STRING$(5, "*")
VAL	✓	✓	✓	Converts string to number	V = VAL("123")

Program Control

Keyword	Z80	6502	6809	Description	Usage Example
CONT	✓	✓	✓	Continues program execution	CONT
END	✓	✓	✓	Ends program	END
FOR/NEXT	✓	✓	✓	Loop structure	FOR I=1 TO 10 : PRINT I : NEXT I
GOSUB	✓	✓	✓	Calls subroutine	GOSUB 1000
GOTO	✓	✓	✓	Jumps to line number	GOTO 100
IF/THEN	✓	✓	✓	Conditional execution	IF X=5 THEN PRINT "YES"
ON GOSUB	-	-	✓	Multiple branch subroutine	ON X GOSUB 100,200,300
ON GOTO	-	-	✓	Multiple branch jump	ON X GOTO 100,200,300
RETURN	✓	✓	✓	Returns from subroutine	RETURN
STOP	✓	✓	✓	Halts program execution	STOP

Data and Variables

Keyword	Z80	6502	6809	Description	Usage Example
DATA	✓	✓	✓	Stores program data	DATA 100,200,"TEXT"
DEF FN	✓	✓	✓	Defines function	DEF FNA(X)=X*X+2
DIM	✓	✓	✓	Declares array dimensions	DIM A(10),B$(20)
INPUT	✓	✓	✓	Accepts user input	INPUT "Name?";N$
LET	✓	✓	✓	Assigns variable value	LET A=5 or A=5
LINE INPUT	-	-	✓	Inputs entire line	LINE INPUT "Text?";A$
READ	✓	✓	✓	Reads DATA values	READ A,B,C$
RESTORE	✓	✓	✓	Resets DATA pointer	RESTORE

System and Memory

Keyword	Z80	6502	6809	Description	Usage Example
DEEK	✓	-	-	Reads word from memory	D = DEEK(16384)
DOKE	✓	-	-	Writes word to memory	DOKE 16384,12345
FRE	✓	✓	-	Returns free memory	F = FRE(0)
INP	✓	-	-	Reads from I/O port	I = INP(255)
MEM	-	-	✓	Returns memory size	M = MEM
OUT	✓	-	-	Writes to I/O port	OUT 255,10
PEEK	✓	✓	✓	Reads byte from memory	P = PEEK(16384)
POKE	✓	✓	✓	Writes byte to memory	POKE 16384,255
USR	✓	✓	✓	Calls machine language routine	U = USR(32768)
VARPTR	-	-	✓	Returns variable address	V = VARPTR(A)

Program Editing

Keyword	Z80	6502	6809	Description	Usage Example
CLEAR	✓	✓	✓	Clears variables	CLEAR
CLS	✓	-	-	Clears screen	CLS
DEL	-	-	✓	Deletes program lines	DEL 100-200
EDIT	-	-	✓	Edits program line	EDIT 100
LIST	✓	✓	✓	Lists program	LIST or LIST 100-200
NEW	✓	✓	✓	Clears program	NEW
RENUM	-	-	✓	Renumbers program lines	RENUM 100,10
RUN	✓	✓	✓	Executes program	RUN or RUN 100
TRON/TROFF	-	-	✓	Trace mode on/off	TRON or TROFF

Z80 BASIC Specific Extensions (v4.7b)

Keyword	Description	Usage Example
HEX$(nn)	Converts signed integer to hex string	H$ = HEX$(255)
BIN$(nn)	Converts signed integer to binary string	B$ = BIN$(15)
&Hnn	Interprets nn as hexadecimal value	X = &H1F
&Bnn	Interprets nn as binary value	Y = &B1010

Operators

Operator	Z80	6502	6809	Description	Usage Example
+	✓	✓	✓	Addition	A = B + C
-	✓	✓	✓	Subtraction	X = Y - Z
*	✓	✓	✓	Multiplication	P = Q * R
/	✓	✓	✓	Division	D = N / 2
^	✓	✓	✓	Exponentiation	E = 2 ^ 3
AND	✓	✓	✓	Logical AND	IF A>0 AND B<10 THEN...
OR	✓	✓	✓	Logical OR	IF X=0 OR Y=0 THEN...
NOT	✓	✓	✓	Logical NOT	IF NOT A THEN...
>	✓	✓	✓	Greater than	IF X > 10 THEN...
<	✓	✓	✓	Less than	IF Y < 5 THEN...
=	✓	✓	✓	Equal to	IF A = B THEN...
&	-	-	✓	Bitwise AND	R = X & Y

Notes:

1. Z80 BASIC is the most commonly used version for CP/M systems
2. 6502 BASIC is a Microsoft BASIC variant
3. 6809 BASIC has the most extensive command set but lacks storage commands
4. None of the 6502 and 6809 variants support CSAVE/CLOAD operations

Each example shows the most common usage pattern for the command. Many commands have additional optional parameters or alternate syntaxes not shown in these basic examples.