Tag Archives: hardware

6502 news

Divers new additions to the 6502 project

Above is my design for a hex keyboard to enter opcodes in hex using a simple monitor program.
i used a 74ls922 which can decode a 4×4 matrix. I’d rather had a 74ls723 which can encode 20 keys.

Nowhere to be found. So i have to think of a new plan.

Now it is configured as follows:

CDEF
89AB
4567
0123

When pressing the alternate key

addr
(to implement)
run
(1/2 implemented)
reset
(to implement)
step instruction
(to implement)
memory next
memory previous
PCB design for matrix hexboard with place for notes

Meanwhile i’ve ordered new keys (the ones i’ve been using for my photomanager project and wnat to have a setup like this:

??addrrunreset
CDEF?
89ABstep
4567mem next
0123mem prev

When you want to show the status of busses and alike, you can’t use a led and restistor directly on the bus, it will require too much current.
So i’ve been using below schematic which uses a darlington array.

Now i can display databus, address bus and i’ve been using this for address decoding logic and hex keyboard.

I’ve implemented a second VIA chip, and ordered components to amplify the SID sound part

6502 cont.

UPDATE: 20220823 Sid working

Kicad VIA/PIA tester

Above is my Kicad design (reverse engineering print below, which was made for my 6802CPU, which i could use to test the 6822 PIA)
The 6822 is simular to 6502 in design. So i’m going to redo this for my 6502.
The 7 segment displays are a start of hex-keyboard/display combo i’m going to post more of in the next days.

Below a part of the rom for the LCD dual line display.

Part of the ROM assembly code, top part is text (o.a. japanese)

Started to write routines which i can call to manipulate the display. Setting the pointer to a message, setting the line to use and a subset of controlls like: Center, Right, binary to ascii, scrolling, etcetera

        lda #0             ; set line number
        sta lineno         ; store
        jsr gotoline       ; goto line in display
        lda #<message      ; get address from message and store for printline subroutine
        sta messagestore
        lda #>message
        sta messagestore+1
        jsr printline      ; print

        lda #1  ; set line number
        sta lineno      ; store
        jsr gotoline
        lda #<message2
        sta messagestore
        lda #>message2
        sta messagestore+1
        jsr printline

Above additions:
New address decoder
Below left the new graphical display, below right a test board which shows address lines and decoded chip-enable lines.

A15 high -> ROM
A15 && A14 low -> RAM
combination of A15 low and A14 high – A13 and A12 wil select peripherals.

Adress decoding

Above is a start of a wirewrapped version, i also started a PCB design in KIcad that will continuously be changed as i alter designs.

UPDATE SID Working! Using new address decoder.

SID = $7000

makesound:
	lda #0
	sta SID+$5 ; Channel1 - attack/decay
	
	lda #250
	sta SID+$6 ; Channel1 - Sustain/Release
	
	lda #$95
	sta SID+$0 ; Channel1 - Frequency low-byte
	
	lda #$44
	sta SID+$1 ; Channel1 - Frequency high-byte

	lda #%00100001
	sta SID+$4 ; SAW + Gate

	lda #$0f
	sta SID+$18 ; Volume max

C64 Cartridge

Got IC Sockets in today, together with other goodies.

So i soldered the C64 Cartridge print.

Putting a bin on the eeprom

sudo minipro -p AT28C64 -w 8kcart.bin

Welll .. allmost working.
Some strange artifacts, but is running.

The long wire … is a ‘jumper’ .. i cant find ONE (free) jumper in my lab!

6502 progress

Added second VIA chip. (For hex keyboard)

Skipped the sound setups with simple components or the Yamaha chip. Straight to the commodore SID chip. Added a amplifier and a speaker.

Added ROM functions for line printing. Picture with 2 lines, and my name in Japanese

Now I have to wait for components. I’ve made a simulation for a address decoder.

Rest I’ve put in previous posts as updates.

Meanwhile testing 6502 apps on Android


74 Series logic, Rom, Gal, Pal, FPGA for Address decoding

For accessing the different components in computers you have to use the Address Bus.
In most 8 bits computers there are 16 address lines.

The CPU on a 6502 can access 65536 addresses (16 bit ). But most chips in the circuit have just a few address lines.
So the chip to use has to be selected using a CE (chip Enable) signal.

Old article i found on my fileserver from 1984

74 Series logic

Above example uses A15 combined with A14 to address the 16K ROM
When using a 32k rom in the upper part of the memory, a15 can be used as CE

The 74ALS133 is a widely used decoder due to it’s many inputs.

Sometimes not all address lines are used for decoding, then you will get a repetition of the device in the memory map.

Above 6522 VIA has only 4 address lines RS0-RS3. But 2 chipselect pins (CS).
If you connect the chip as below.

A15 A14 A13 A12 A11 A10 A09 A08 A07 A06 A05 A04 A03 A02 A01 A00
CS1 CS2  NC  NC  NC  NC  NC  NC  NC  NC  NC  NC CR3 CR2 CR1 CR0
(NC - not connected, and CS2 is inverted!)

The chip would be selected when A15 is 1 and A14 is 0, A13-A04 it would not listen to. So its 4 bits addresses (total 16), would be repeated in a block $8000-$BFFF (10xx xxxx xxxx aaaa) 16384 addresses for 16 addresses on the 6522

ROM

Another simple solution to get a more precise address decoder without using a lot of components is using a ROM.
But this wil only work for low speeds!
A eeprom is relative cheap

Example ROM as chip enable/select

PAL PLA GAL

With these devices you can “program” a schematic which works as above example’s of the 74 series. But now you can do it using only one component.

PALs and PLAs are fuse-programmed, some are erasable like (e)eprom.
Below a example of the code.
Most of the PAL/PLA/GAL are hard to get and obsolete

;PALASM Design Description
;---------------------------------- Declaration Segment ------------
TITLE    pRAM PC_interface Address Decoder
PATTERN  pRAM97A.pds
REVISION H
AUTHOR   Trevor Clarkson
COMPANY  EEE KCL
DATE     30/05/97

CHIP  decode  PALCE20V8

;---------------------------------- PIN Declarations ---------------
PIN  1          AEN                                   COMBINATORIAL ; INPUT
PIN  2          A9                                    COMBINATORIAL ; INPUT
PIN  3          A8                                    COMBINATORIAL ; INPUT
PIN  4          A7                                    COMBINATORIAL ; INPUT
PIN  5          A6                                    COMBINATORIAL ; INPUT
PIN  6          A5                                    COMBINATORIAL ; INPUT
PIN  7          A4                                    COMBINATORIAL ; INPUT
PIN  8          A3                                    COMBINATORIAL ; INPUT
PIN  9          A2                                    COMBINATORIAL ; INPUT
PIN  10         A1                                    COMBINATORIAL ; INPUT
PIN  11         IOW                                   COMBINATORIAL ; INPUT
PIN  12         GND
PIN  13         IOR                                   COMBINATORIAL ; INPUT
PIN  14         ACK_HALT                              COMBINATORIAL ; INPUT
PIN  15         PLS_EN                                COMBINATORIAL ; OUTPUT
PIN  16         BRDW                                  COMBINATORIAL ; OUTPUT
PIN  17         MOD_CTRL                              COMBINATORIAL ; OUTPUT
PIN  18         RAM_ACCESS                            COMBINATORIAL ; OUTPUT
PIN  19         IO_16                                 COMBINATORIAL ; OUTPUT
PIN  20         LATCH_MOD                             COMBINATORIAL ; OUTPUT
PIN  21         LATCH_ADD                             COMBINATORIAL ; OUTPUT
PIN  22         P300                                  COMBINATORIAL ; OUTPUT
PIN  23         P300IN                                COMBINATORIAL ; INPUT
PIN  24         VCC

;PC address decoding functions (not all in this PAL)
;uses latched address to provide low-order address lines to pRAM/RAM
;       A3      A2      A1      R/W     Addr    Function
;       0       0       0       R       300     MFF_0
;                               W               not used
;       0       0       1       R       302     MFF_1
;                               W               not used
;       0       1       0       R       304     MFF_2
;                               W               not used
;       0       1       1       R       306     MFF_3
;                               W               Latch Module Number
;       1       0       0       R       308     PLS_Status  (pRAM status)
;                               W               PLS_Control (pRAM control)
;       1       0       1       R       30A     Weight/Connection-
;                               W                Pointer RAM access
;       1       1       0       R       30C     not used
;                               W               Latched RAM address
;       1       1       1       R       30E     not used
;                               W               pRAM_256 module control
;
; NB. IO_16 must be tri-stated when not in use

;----------------------------------- Boolean Equation Segment ------
EQUATIONS

/P300 = A9*A8*/A7*/A6*/A5*/A4*/IOR + A9*A8*/A7*/A6*/A5*/A4*/IOW

/BRDW = /P300IN * /IOW

/PLS_EN = /P300IN*/A3*/IOR + /P300IN*A3*/A2*/A1

; MOD_CTRL is active HIGH
MOD_CTRL = ACK_HALT * /BRDW * A3 * A2 * A1 * /IOW

; RAM_ACCESS is active HIGH
RAM_ACCESS = ACK_HALT * /P300IN * A3 * /A2 * A1

IO_16 = GND
IO_16.TRST = /P300IN
; enable 16-bit transfers

; LATCH_MOD is active HIGH
LATCH_MOD = /BRDW * /A3 * A2 * A1

; LATCH_ADD is active HIGH
LATCH_ADD = /BRDW * A3 * A2 * /A1

;----------------------------------- Simulation Segment ------------
SIMULATION
TRACE_ON A9 A8 A7 A6 A5 A4 IOR /IOW /BRDW /PLS_EN MOD_CTRL RAM_ACCESS IO_16 LATCH_MOD LATCH_ADD ACK_HALT /P300 /P300IN
SETF /A9 /A8 /A7 /A6 /A5 /A4 /A3 /A2 /A1 IOR IOW /ACK_HALT /P300IN
SETF /IOW ; test P300 doesn't respond
SETF IOW /IOR ; test P300 doesn't respond
SETF IOR
SETF A9 A8 /A7 /A6 /A5 /A4 /IOR /P300IN
SETF A1
SETF A2 /A1
SETF A1 ; read mff0-3
SETF IOR /IOW ; test P300 and BRDW
SETF /A3 A2 A1 ; test Latch Module No
SETF IOW A3 A2 A1 ; MOD-CTRL not active until ACK_HALT
SETF ACK_HALT /IOW
SETF IOW /ACK_HALT
SETF A3 /A2 A1 ; check RAM_ACCESS
SETF ACK_HALT /IOW
SETF /ACK_HALT IOW
SETF ACK_HALT /IOR ; check READ and WRITE to RAM
SETF IOR P300IN
SETF /A3 A2 A1
SETF /ACK_HALT /P300IN
SETF IOW
SETF /A3 A2 A1 /IOW ; check LATCH_MOD 
SETF IOW
SETF A3 A2 /A1
SETF /IOW       ; check LATCH_ADD
SETF /A3 /A2 /A1 ; shouldn't happen normally

TRACE_OFF
;-------------------------------------------------------------------

FPGA

Example FPGA code. A solution which is too fancy for my 6502.
// Verilog code for decoder 
// 5-input AND gate 
module AND_5_input(g,a,b,c,d,e);
  output g;
  input a,b,c,d,e;
  and #(50) and1(f1,a,b,c,d),
            and2(g,f1,e);
endmodule
// fpga4student.com: FPGA projects, Verilog projects, VHDL projects 
// Verilog code for decoder 
// Decoder top level Verilog code using 5-input AND gates 
module dec5to32(Out,Adr);
input [4:0] Adr; // Adr=Address of register
output [31:0] Out;
not #(50) Inv4(Nota, Adr[4]);
not #(50) Inv3(Notb, Adr[3]);
not #(50) Inv2(Notc, Adr[2]);
not #(50) Inv1(Notd, Adr[1]);
not #(50) Inv0(Note, Adr[0]);

AND_5_input a0(Out[0],  Nota,Notb,Notc,Notd,Note); // 00000
AND_5_input a1(Out[1],  Nota,Notb,Notc,Notd,Adr[0]); // 00001
AND_5_input a2(Out[2],  Nota,Notb,Notc,Adr[1],Note); //00010
AND_5_input a3(Out[3],  Nota,Notb,Notc,Adr[1],Adr[0]);
AND_5_input a4(Out[4],  Nota,Notb,Adr[2],Notd,Note);
AND_5_input a5(Out[5],  Nota,Notb,Adr[2],Notd,Adr[0]);
AND_5_input a6(Out[6],  Nota,Notb,Adr[2],Adr[1],Note);
AND_5_input a7(Out[7],  Nota,Notb,Adr[2],Adr[1],Adr[0]);
AND_5_input a8(Out[8],    Nota,Adr[3],Notc,Notd,Note);
AND_5_input a9(Out[9],    Nota,Adr[3],Notc,Notd,Adr[0]);
AND_5_input a10(Out[10],  Nota,Adr[3],Notc,Adr[1],Note);
AND_5_input a11(Out[11],  Nota,Adr[3],Notc,Adr[1],Adr[0]);
AND_5_input a12(Out[12],  Nota,Adr[3],Adr[2],Notd,Note);
AND_5_input a13(Out[13],  Nota,Adr[3],Adr[2],Notd,Adr[0]);
AND_5_input a14(Out[14],  Nota,Adr[3],Adr[2],Adr[1],Note);
AND_5_input a15(Out[15],  Nota,Adr[3],Adr[2],Adr[1],Adr[0]);
AND_5_input a16(Out[16],  Adr[4],Notb,Notc,Notd,Note);
AND_5_input a17(Out[17],  Adr[4],Notb,Notc,Notd,Adr[0]);
AND_5_input a18(Out[18],  Adr[4],Notb,Notc,Adr[1],Note);
AND_5_input a19(Out[19],  Adr[4],Notb,Notc,Adr[1],Adr[0]);
AND_5_input a20(Out[20],  Adr[4],Notb,Adr[2],Notd,Note);
AND_5_input a21(Out[21],  Adr[4],Notb,Adr[2],Notd,Adr[0]);
AND_5_input a22(Out[22],  Adr[4],Notb,Adr[2],Adr[1],Note);
AND_5_input a23(Out[23],  Adr[4],Notb,Adr[2],Adr[1],Adr[0]);
AND_5_input a24(Out[24],  Adr[4],Adr[3],Notc,Notd,Note);
AND_5_input a25(Out[25],  Adr[4],Adr[3],Notc,Notd,Adr[0]);
AND_5_input a26(Out[26],  Adr[4],Adr[3],Notc,Adr[1],Note);
AND_5_input a27(Out[27],  Adr[4],Adr[3],Notc,Adr[1],Adr[0]);
AND_5_input a28(Out[28],  Adr[4],Adr[3],Adr[2],Notd,Note);
AND_5_input a29(Out[29],  Adr[4],Adr[3],Adr[2],Notd,Adr[0]);
AND_5_input a30(Out[30],  Adr[4],Adr[3],Adr[2],Adr[1],Note);
AND_5_input a31(Out[31],  Adr[4],Adr[3],Adr[2],Adr[1],Adr[0]); // 11111
endmodule

Example of Ice studio FPGA programming

Conslusion:

For now i will use the 74 logic. But i definitely will revisit FPGA’s

Scavenging parts and schematics

Searching for parts .. from other projects

I want to make a new clock module using a bare ATmega328 running on a 16mhz crystal. This to provide a clock for my 6502 computer.

Using a display and a rotary encoder I want to create a clock module which generates a 50/50 duty cycle clock 1Hz – 1 MHz.

Input module for my 6502 will be 5 buttons. (For now) that’s what’s left on the VIA on port A. (Rest is used by the display). The display i’m going to place directly on the bus. But I already ordered a second VIA.  Matrix keyboard will be next. Then I will use the buttons in the picture for shift/alternate buttons. Because I’ll need about 25 keys. (See other posts) . I’ll probably end up making that one myself.

Wire wrap

The lost ancient art of wire wrapping.

{funny story]
In 2019 i wanted to make a simple probe, which could detect 0 or 1 or a pulse. I wanted to make this on a little print using wirewrap wires and IC sockets. (I still have the tool which i used in the 90s.)
When going to a well-known electronics shop in Den Hague. A great shop to get all kinds of oldskool electronics. But i’m getting ahead of the story.
This shop has a lot of components for all kinds of electronics. New and what it looked like de-soldered component from boards or bought from old going-out-of-business shops or factories. Stuff you needed for 60s equipment.
Well i was at the counter, asking a old guy.
“Do you have wire-wrap wire”
He said: ” No that’s old skool” ….
{/funny story]

The wirewrap tool has a cable stripper. After stripping you would put a short part in the tool, place the tool over a IC pin and turning would wrap the wire on the pins.
You could stack multiple connections on one pin.
Removing could be done by turning the tool counterclockwise.
Sometimes you had to remove the one closest to the print, replacing all wires. (Or cut the wrong/not needed wire and leave it in place … )

I’m thinking of moving my breadboard 6502 to a wirewrapped version.
All my old boards are gone .. before i got a digital camera .. 🙁

Example from a 8031 setup of a friend of mine

6502 progress

UPDATE: 20220815, 20220814, 20220815, 20230202

Flashing ROMs .. (eeproms). It used to be a pain in the *$$.
Burning took a looong time. But clearing one with UV took .. 20 minutes or so. Using one of these:

Altered clock module

  • Changed button press
  • Dipswitches for more speed control (red .. upper left)

Changed Rom/Ram

  • Changed addressing
  • Added RAM
  • ZIF Socket for ROM

VIC 6522

  • Fixed clock
  • Added buttons for interrupt

Display

  • Display works now
  • To test: Create Address logic to access display without VIA
    Can work, but not at high speed clock. Stays behind VIA
  • To buy: st7920 lcd 128×64

Generic improvements

  • Rewired most parts, using color codes
    (Blue data, Yellow Address and so on)
  • Added leds on data and address bus using ULN2803 darlington arrays
  • 100nF Decoupling capacitors on the power rails

To do’s or ‘have to look into’s’

  • For sound i planned to use a General Instrument AY-3-8910, it is somewhere in my Lab, i know it is.
    I saved this chip and a SID for my Amiga addon soundcard.
    Where are my plans for the simple v1 setup? (FOUND IT)

  • I have to start writing rom functions for display usage. Like
    JSR $ff00 – Clear screen subroutine .. etc
  • I’m scraping information from websites, to get started on my clock controller.
    ATmega328 with ssd1306 display and rotary encoder/dip switches

Notes about the movie:
Left side is Arduino IDE monitor reading Addressbus and Databus.
(I’m going to try to rewrite this to realtime disassemble)
Resetting system.
Stepping CPU with manual clock pulses.
Start vector being read at $FFFC/$FFFD.
Program being run from $8000.
Set clock on automatic ( ~ about 150 Hz )
Last opcodes you see a JMP loop 4C 2F 80, that is JMP $802F
Display enlarged on video, was not visible on movie i took on mobile.
(Wrong angle?)

Breadboard overview

Clock moduleReset module + Crystal
CPU + nmi/int buttonsRAM and ROM
Address decode + Bus divideAddres/Data bus leds
6522 VIA + Display2nd via + Buttons
?(sound board)

TIL: 6502 can run without ram only rom,expect when using JSR … which uses a program stack in RAM

TODO:

  • Make Clock module and 1Mhz Crystal switchable
  • NMI and INT debounce maken
  • Software buttons
  • Buy new darlingtons, for controlbus!
    • r/w, int, chip enables, etc
  • Labels on chips/breadboards

C64 PRG to cartridge.

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??!?

root@battlestation:/home/fash/Projects/minipro# hexdump -C /tmp/8085.prg  | head
00000000  01 08 1e 08 c5 07 9e 32  30 38 30 20 42 59 20 4d  |.......2080 BY M|
00000010  41 52 54 49 4e 20 4d 45  59 45 52 49 4e 4b 00 00  |ARTIN MEYERINK..|
00000020  00 20 ec 08 20 7f 19 20  2b 2c 20 11 19 20 b8 08  |. .. .. +, .. ..|
00000030  20 20 2c 20 a0 2c 20 f2  2c 20 11 e1 4c 00 15 aa  |  , ., ., ..L...|
00000040  aa a2 06 ad b7 08 9d 48  d8 bd 48 04 20 88 39 9d  |.......H..H. .9.|
00000050  48 04 ca 10 ee a9 60 8d  4c 04 4c 50 47 00 a9 d0  |H.....`.L.LPG...|
00000060  2c a9 f0 8d 45 1f 4c 11  e1 1e 93 0d 20 20 4d 41  |,...E.L.....  MA|
00000070  52 54 49 4e 20 4d 45 59  45 52 49 4e 4b 27 53 0d  |RTIN MEYERINK'S.|
00000080  0d 20 38 30 38 35 20 45  4d 55 4c 41 54 4f 52 20  |. 8085 EMULATOR |
00000090  20 56 34 2e 38 30 0d 0d  20 20 28 43 29 20 31 20  | V4.80..  (C) 1 |

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!

Altair 8800

After a whole day soldering yesterday, ending up with a wire mess.
Which didn’t work at the end…

Starting measuring some things, and create some test sketches (led blinky tests)
I found out that the main problem was not having the red switches connected to GND.
Blue switches where upside down, this was a easy fix. Because these are ON-ON switches, and where already connected to a common line.
Then a mixup between D0 and D6 (wires crossed)
And it is working! Made some lines and lettering on the frontplate after some playing around.

Weird to input stuff in octal (group of 3 bits)