While still having a love-hate relationship with Visual Studio (I’m a Vim guy), here is my C64 coding setup. (for now)
Needed: Vice (C64 emulator (and more)) C64 Debugger (embeds above in an awesome debugger) Visual Studio Kickass C64 assembler (you need java for this) (http://theweb.dk/KickAssembler/Main.html)
Visual Studio click extensions and add kickass by Captain Jinx
https://sourceforge.net/projects/c64-debugger/ This is Commodore 64, Atari XL/XE and NES code and memory debugger that works in real time. It is quick prototyping tool where you can play with Commodore 64 machine and its internals.
Awesome debugger, many many options. Read the README
I’ve got mostly installed in /data Change accordingly
Create new file, press ctrl-shift-p and invoke kickass debug!
Below board replaces 2364 (8k) with a 28c256 (32k 4 roms) socket. My design in Kicad
The rom can be selected using the pressing restore while starting the C64. ( This button press to select is not my idea but I liked it, when I find the original idea I’ll post it.
After ordering and testing, I’ll attach the Gerber files.
JiffyDOS is an enhanced DOS for the C64. The software is programmed onto ROM chips that replace the Kernal ROM chip on the motherboard and the DOS ROM chip in the disk drive. JiffyDOS is intended to provide greater speed, commands and convenience than on stock systems.
The 1541 drive is a computer on its own, using a 6502 and VIA chips. (See other pages) (C64 uses a 6510, that is the same slightly modified version of the 6502) A cool example of the drive being an OS/computer on its own: https://www.youtube.com/watch?v=zprSxCMlECA
Some notes:
I want to use a larger rom and using the higher address lines as kernal selector. Address line A13 and A14 can be used as selector
There is a schematic out there using runstop at boottime to do de selection of the rom part
Did I misspell kernel? NO (Below from Wikipedia)
The KERNAL was known as kernel inside of Commodore since the PET days, but in 1980 Robert Russell misspelled the word as kernal in his notebooks. When Commodore technical writers Neil Harris and Andy Finkel collected Russell’s notes and used them as the basis for the VIC-20 programmer’s manual, the misspelling followed them along and stuck.
Original Kernal: 901227-03 8-kilobyte 2364 ROM 4K * 8 bits PROM
28C265 = 32K * 8bits
Diffference in ROM size AND there are some other pin placements.
V0.1
Romselect should be /(a15 * a14 * a13) depending on ram/rom switch.
SEL0
SEL1
0
0
rom0
0
1
rom1
1
0
rom2
1
1
rom3
$E000-$FFFF – ROM 57344-65535
KERNAL ROM or RAM area (8192 bytes); depends on the value of bits #0-#2 of the processor port at memory address $0001 $FFFA-$FFFF – hardware vectors
Cartridge printEeproms 8k and 32k (also for 6502 project)Eeprom programmer
I’ve got the tools and Bigred made me enthusiastic again. My goal is to make a C64 Cartridge from a PRG. And Not any program, it is the 8085 Emulator from Sepp.
Serveral problems i have to ‘fix’
The program is 17K, Cartridges can only be 16K. So i have to use 2x 8K and compress the data. This means it have to be uncompressed at start time. ( I was thinking of using exomiser for this )
Program starts normally at $0820 and probably is not optimised to run anywhere else. So a starting routine has to copy the program from cartridge memory to the correct location
Luckily i have the source! How cool is that
For version 4.73 it states : Starting at $0820 .. but my hexdump is off by one??!?
00000020 00 20 ec starts with 00 at $0020 .. and not 20 ?!?!
Tools used until now:
Vice – C64 Emulator x64 -cartcrt 8085.crt
c1541 – Linux disk tool for C64 images. Used this to extract the 8085emulator PRG
prg2crt.py – a convertor from PRG to a cartrid file which can be used by Vice python2 prg2crt.py 8085.prg 8085.crt
minipro – eeprom programming tool for Linux minipro -p AT28C64 -w /tmp/test.bin
cartconv (tool from vice to convert crt <-> bin) cartconv -t normal -i test.bin -n ‘my cart’ -o test.crt
xa – Cross assembler 65xx/R65C02/65816
ACME – the ACME Crossassembler for Multiple Environments
Memory Map C64 – source c64-wiki.com
Card Low starts at $8000, so that’s the place where those roms are going to be. To place on this address:
Copy routine : from ($8000 + this copy routine) to $0820 When to decompress?? jmp routine to $0820
A cartridge file >16K and with his emulation headers seems to work??!
Also nice: Magic Desk Cartridge Generator V3.0
UPDATE: 20220811
exomizer sfx 0x0820 8085.prg -o data.exo # Compress and start at 0x0820
xa frame.asm -o frame.bin # Add code and write binary
x64 --cart16 frame.bin # Test cartridge with Vice
frame.asm
;----------------------------------------------------------
; example usage
; xa frame.asm -o frame.bin
; cartconv -t normal -i frame.bin -n 'my cart' -o frame.crt
; x64 -cartcrt frame.crt
;----------------------------------------------------------
;no load-adress for bin-file, so no header here
*=$8000
.word launcher ;cold start
.word launcher ;warm start
.byte $c3 ;c
.byte $c2 ;b
.byte $cd ;m
.byte $38 ;8
.byte $30 ;0
launcher
stx $d016
jsr $fda3 ;prepare irq
jsr $fd50 ;init memory
jsr $fd15 ;init i/o
jsr $ff5b ;init video
;make sure this sets up everything you need,
;the calls above are probably sufficient
ldx #$fb
txs
;set up starting code outside of cartridge-area
move_starter
ldx #(starter_end-starter_start)
loop1
lda starter_start,x
sta $100,x
dex
bpl loop1
jmp $100
;---------------------------------
starter_start
ldx #$40 ;64 pages = 256 * 64 = 16384 Bytes
ldy #0
loop
src
lda exomized_data,y
dst
sta $801,y
iny
bne loop
inc src+2-starter_start+$100
inc dst+2-starter_start+$100
dex
bpl loop
;make sure settings for $01 and IRQ etc are correct for your code
;remember THIS table from AAY64:
; Bit+-------------+-----------+------------+
; 210| $8000-$BFFF |$D000-$DFFF|$E000-$FFFF |
; +---+---+-------------+-----------+------------+
; | 7 |111| Cart.+Basic | I/O | Kernal ROM |
; +---+---+-------------+-----------+------------+
; | 6 |110| RAM | I/O | Kernal ROM |
; +---+---+-------------+-----------+------------+
; | 5 |101| RAM | I/O | RAM |
; +---+---+-------------+-----------+------------+
; | 4 |100| RAM | RAM | RAM |
; +---+---+-------------+-----------+------------+
; | 3 |011| Cart.+Basic | Char. ROM | Kernal ROM |
; +---+---+-------------+-----------+------------+
; | 2 |010| RAM | Char. ROM | Kernal ROM |
; +---+---+-------------+-----------+------------+
; | 1 |001| RAM | Char. ROM | RAM |
; +---+---+-------------+-----------+------------+
; | 0 |000| RAM | RAM | RAM |
; +---+---+-------------+-----------+------------+
lda #$35 ;cart is always on instead of BASIC unless it can be switched off via software
sta $01
jmp $80d ;for exomizer, i.e.
starter_end
;----------------------------------
exomized_data
.bin 2,0,"data.exo"
;syntax for exomizer 2.0.1:
;exomizer sfx sys game.prg -o data.exo
main_file_end
;fill up full $4000 bytes for bin file ($c000-$8000=$4000)
.dsb ($c000-main_file_end),0
Exomiser info
Reading "8085.prg", loading from $0801 to $4CE9.
Crunching from $0801 to $4CE9.
Phase 1: Instrumenting file
-----------------------------
Length of indata: 17640 bytes.
[building.directed.acyclic.graph.building.directed.acyclic.graph.]
Instrumenting file, done.
Phase 2: Calculating encoding
-----------------------------
pass 1: optimizing ..
[finding.shortest.path.finding.shortest.path.finding.shortest.pat]
size 80273.0 bits ~10035 bytes
pass 2: optimizing ..
[finding.shortest.path.finding.shortest.path.finding.shortest.pat]
size 80039.0 bits ~10005 bytes
pass 3: optimizing ..
Calculating encoding, done.
Phase 3: Generating output file
------------------------------
Encoding: 1101112133423160,1122,2010223445667788,032144406789BBCD
Length of crunched data: 10034 bytes.
Crunched data reduced 7606 bytes (43.12%)
Target is self-decrunching C64 executable,
jmp address $0820.
Writing "data.exo" as prg, saving from $0801 to $304C.
Memory layout: |Start |End |
Crunched data | $07E7| $2F18|
Decrunched data | $0801| $4CE9|
Decrunch table | $0334| $03D0|
Decruncher | $00FD| $01C0| and $9F,$A7,$AE,$AF
Decrunch effect writes to $DBE7.
Decruncher: |Enter |During|Exit |
RAM config | $37| $37| $37|
IRQ enabled | 1| 1| 1|
UPDATE:20230126
; CODE COPY FROM http://www.lemon64.com/forum/viewtopic.php?t=60786&sid=2559442c8b963d7aac27cb13b493f372
; Thanks for posting: Richard of TND
; this is for a 16KB cart, using ACME!!
!to "mycart.crt",cart16crt
scr = $0400
DecrunchADDR = 2061 ;SYS 2061 (HEX $080D)
*=$8000
!word launcher
!word launcher
!byte $c3,$c2,$cd,$38,$30 ;CBM 80
launcher
sei
stx $d016
jsr $fda3 ;prepare irq
jsr $fd50 ;input memory
jsr $fd15 ;initialise i/o
jsr $ff5b ;initialise video memory
;For a more professional boot up. Make
;the border and screen black. AFTER
;the video memory, etc has finished.
lda #$00
sta $d020
sta $d021
cli
;Switch off the screen.
lda $d011
and #%11101111
sta $d011
;Move transfer code over to the screen
;memory.
ldx #$00
tloop lda transfer,x
sta scr,x
inx
bne tloop
jmp scr
transfer
ldx #$00
tr1 lda linkedgame,x ;Move from linked address
sta $0801,x ;Direct to BASIC start address
inx
bne tr1
inc scr+4
inc scr+7
lda scr+4
bne transfer
jsr $e453 ;load basic vectors
jsr $e3bf ;init basic ram
ldx #$fb
txs
;Execute the game, by jumping to the
;de-cruncher's start address.
;jmp $0820
jmp DecrunchADDR
;Link crunched game as a PRG file to memory after
;the cartridge build code.
linkedgame
!bin "8085sys.prg",,2
FileSize = *
!if FileSize >$c000 {
!error "FILE SIZE IS TOO BIG TO FIT 16KB CARTRIDGE"
} else {
*=$c000
}
Exomizer:
exomizer sfx sys 8085.prg -o 8085sys.prg
Reading "8085.prg", loading from $0801 to $4CE9.
Crunching from $0801 to $4CE9.
Phase 1: Instrumenting file
-----------------------------
Length of indata: 17640 bytes.
[building.directed.acyclic.graph.building.directed.acyclic.graph.]
Instrumenting file, done.
Phase 2: Calculating encoding
-----------------------------
pass 1: optimizing ..
[finding.shortest.path.finding.shortest.path.finding.shortest.pat]
size 80273.0 bits ~10035 bytes
pass 2: optimizing ..
[finding.shortest.path.finding.shortest.path.finding.shortest.pat]
size 80039.0 bits ~10005 bytes
pass 3: optimizing ..
Calculating encoding, done.
Phase 3: Generating output file
------------------------------
Encoding: 1101112133423160,1122,2010223445667788,032144406789BBCD
Length of crunched data: 10034 bytes.
Crunched data reduced 7606 bytes (43.12%)
Target is self-decrunching C64 executable,
jmp address $0820.
Writing "8085sys.prg" as prg, saving from $0801 to $304C.
Memory layout: |Start |End |
Crunched data | $07E7| $2F18|
Decrunched data | $0801| $4CE9|
Decrunch table | $0334| $03D0|
Decruncher | $00FD| $01C0| and $9F,$A7,$AE,$AF
Decrunch effect writes to $DBE7.
Decruncher: |Enter |During|Exit |
RAM config | $37| $37| $37|
IRQ enabled | 1| 1| 1|
exomizer sfx $\0801 8085.prg -o 8085out.prg
Reading "8085.prg", loading from $0801 to $4CE9.
Crunching from $0801 to $4CE9.
Phase 1: Instrumenting file
-----------------------------
Length of indata: 17640 bytes.
[building.directed.acyclic.graph.building.directed.acyclic.graph.]
Instrumenting file, done.
Phase 2: Calculating encoding
-----------------------------
pass 1: optimizing ..
[finding.shortest.path.finding.shortest.path.finding.shortest.pat]
size 80273.0 bits ~10035 bytes
pass 2: optimizing ..
[finding.shortest.path.finding.shortest.path.finding.shortest.pat]
size 80039.0 bits ~10005 bytes
pass 3: optimizing ..
Calculating encoding, done.
Phase 3: Generating output file
------------------------------
Encoding: 1101112133423160,1122,2010223445667788,032144406789BBCD
Length of crunched data: 10034 bytes.
Crunched data reduced 7606 bytes (43.12%)
Target is self-decrunching C64 executable,
jmp address $0801.
Writing "8085out.prg" as prg, saving from $0801 to $304C.
Memory layout: |Start |End |
Crunched data | $07E7| $2F18|
Decrunched data | $0801| $4CE9|
Decrunch table | $0334| $03D0|
Decruncher | $00FD| $01C0| and $9F,$A7,$AE,$AF
Decrunch effect writes to $DBE7.
Decruncher: |Enter |During|Exit |
RAM config | $37| $37| $37|
IRQ enabled | 1| 1| 1|
This looks okay: (monitor in vice)
Attaching crt in vice
Maybe one of these problems:
1) you CAN NOT use BASIC routines when a cart is inserted (without weird tricks, i.e.
storing BASIC routines on cart etc)
2) you need to be careful about $01 as you may map in ROM at $8000 without expecting it.
Please refer to this if in doubt:
http://unusedino.de/ec64/technical/aay/c64/memcfg.html
[3] You should also be careful about the usage of KERNAL routines as some of them
sweep across BASIC-code as well!
"If something is worth doing, it's worth overdoing."