6809 code try and add multicomp UART
====================================

Run MultiComp for 6809 

6809 sees UART at 0xFFD0 & 0xFFD1 as used in FPGA
6809 sees UART at 0xA000 & 0xA001 as used in SBC

virtual.c emulated enough of UART and used STDIN and STDOUT

build:-
gcc virtual.c 6809v.c -pthread -o virtual

run 6809 code - use q to end. 
./virtual doug.s19
stty sane

Use SBC ExBasicROM.HEX 
The hex file  FPGA has addesses 0000 to 1FFF and used at E000 to FFFF 

It does not run basic as ROMS are not locaated from 0x0000
FPGA UART is at $FFD0 & $FFD1
Grant's 6-chip 6809 computer has UART is at A000-BFFF SERIAL INTERFACE (minimally decoded)

Memory Map

0000-7FFF 32K RAM
8000-9FFF FREE SPACE (8K)
A000-BFFF SERIAL INTERFACE (minimally decoded)
C000-FFFF 16K ROM (BASIC from DB00 TO FFFF, so a large amount of free space suitable for a monitor etc)


/*
 * VirtualMultiComp for 6809 
 * UART at 0xFFD1/0 and uses STDIN and STDOUT
 * 
 * 
 * based on:- Arto Salmi's 6809.
 * http://atjs.mbnet.fi/mc6809/		
 * http://atjs.mbnet.fi/mc6809/6809Emulators/6809.zip
 * 
 * 
 * http://www.searle.wales/			multicomp for 6809.
 * UART at 0xFFD1/0 and 0xA000/1 It uses STDIN and STDOUT
 * 
 * usage: 
 * gcc virtual.c 6809v.c -pthread -o virtual
 * gcc -o virtual virtual.c 6809v.c -pthread 
 *
 * ./virtual doug.s19
 * 
 * stty sane
 * 
 *usage: - loading Grant's modified BASIC for 6809 SBC ( UART @ 0xA000)
 * ./virtual ExBasROM.hex -hex
 * stty sane
 * 
 * NOTE: Use ExBasROM from 6809 SBC, not FPGA version.
 * 
 * backspace or delete do not seem to work yet!
 * It could do with a way to pipe a file to upload code.
 *  
pi@raspberrypiwww:~/Desktop/m68/6809_multicomp $ ./virtual ExBasROM.hex -hex
Loading code...
AS,JF, 1.2, file ExBasROM.hex     press q to quit 
6809 EXTENDED BASIC
(C) 1982 BY MICROSOFT

OK

  * 
  * LIST
10 X=0
20 PRINT "hELLO"
30 PRINT"HEOOL"
40 PRINT "Hello world"
50 X=X+1
60 IF X < 100 THEN GOTO 20
OK
* 
* 10 A$=CHR$(27)
15 PRINT A$
20 PRINT "[103m"
30 PRINT "HELLO"

*/