Execute file on the GBA


	II. How to execute GBA compiled file.

Last change : 20/02/2002

Because the GBA and the PC are not compatible, we will not be able to test our compiled GBA file directly on the PC. To resolve this trouble, we have four way of solutions:

Using an Emulator : the emulator is a PC based software that will translate the GBA instructions, which will be understandable by the PC.
The GBA Development Cartridge: allow the user to write his file on a cartridge, which will be directly inserted on a real GBA.
The MBV2 Cable: allow the user to send the compiled file directly to the GBA using a communication cable. The file is send from the PC to the external ram of the GBA. Because of that, the user is limited to send file less than 256 KBytes. To get more informations about this device go to this link: http://www.devrs.com/gba/files/mbv2faqs.php
The Dumb Cable : this device work has the same way as the MBV2 cable, but is an Home Made device, and also totally free of Rights. To get more informations and software, visit this link: http://www.godsmaze.org/gba/harware/ (spansish language, but the most interresting pages are posted in English).

1) Using an Emulator

a- Download

The best emulator is without any doubt VisualBoy Advance , official homepage is: http://vboy.emuhq.com/index.shtml

b- Installation

uncompress it in the directory of your choice.

c- Running

Launch the "VisualBoyAdvance.exe" program.
In the menu File | Open.
Select a file with extension ".GBA", ".AGB" or ".BIN".
Go to the Options menu and proceed with the setup.
There is an important option for the coders. If, in the menu Options | Emulator, the Synchronize option is selected, execution will be run at the same speed as a real GBA. Otherwise, the execution will be run faster as your computer could. This is an useful option that allow us to observe differences between the speed of execution of the program (ie: improvement of the code, choice of good type of instructions...).

2) The Dumb-Cable (and also the MBV2)

The Dumb-Cable is an home made cable. The only problem is that the PC-transfert-program can only be run under a real DOS window. Furthermore, the transfert doesn't success each time (i've read on internet this cable has 50% of success, my personal work let me has a success of 100% for the file less than 50Kbytes, and 50% for the file around 150 Kbytes). To get the construction instructions and the transfert software you have to follow this link (spanish web site, but interesting pages are posted in English): http://www.godsmaze.org/gba/harware/

The MBV2 cable have to be ordered through Lik-Sang, it cost around 45€ - it is supplied with all necessary sofware. It is more easier to use than the Dumb-Cable, because it works with all the Windows version and has 100% of transfer success. For more information about this product visit this link:
http://www.devrs.com/gba/files/mbv2faqs.php

b- Installation (Dumb-Cable)

The first thing to do is to built the cable. The easy way is to use a stripboard and weld the component on it. This will be cleaner, easier and faster. (Check to the picture below!)

The second thing is to create a DOS boot disk (the transfer program does not work under Windows).
Copy the transfer program named "DMB.EXE" as well as "DOS4GW.EXE" on that disk.

And now, we just have to specially compile our program to work on the external RAM of the GBA. On the net this method is called Multiboot Compilation.

c- Multiboot Compilation (Dumb-Cable and MBV2)

The principle is quite simple, we just have to indicate to the linker that the start adress is 0x2000000 (witch is the External RAM start Address), instead of the usual 0x8000000 (witch is the ROM GamePack Address). The compiled file should have the extention ".MB" and not ".BIN" or ".GBA".

Keep in mind, your compiled file have limitation of 256 KBytes (corresponding to the size of the External Gba RAM).

With ARM SDT :

Compile your source using this ".BAT" File:

"Compil_MB_ARM_SDT.BAT" :

zarmasm -CPU ARM7TDMI -Littleend boot.asm

zarmcpp.exe -c -Wall -Otime -ansic -fpu none -Littleend -cpu ARM7TDMI -apcs /narrow/noswst main.c -o main.o

zarmlink -bin -first boot.o boot.o main.o -map -ro-base 0x02000000 -rw-base 0x03000000 -o Nom_Prg.mb

With GCC 3.0 :

Insert at the beginning of your source, those 2 lines:
#define MULTIBOOT volatile const u8 __gba_multiboot;
MULTIBOOT
And use this following ".BAT" file:

"Compil_MB_GCC.BAT" :

as -mthumb-interwork -o crt0.o crt0.s

gcc -I C:\gccgba\include -c -g -O2 -mthumb-interwork -Wall -save-temps -fverbose-asm main.c 
ld -L C:\gccgba\lib -Ttext 0x02000000 -Tbss 0x03000000 -o Nom_Prg.elf crt0.o main.o -lc -lgcc 
objcopy -v -O binary Nom_Prg.elf Nom_Prg.mb

d- How To Use (Dumb-Cable)

Boot your computer with the floppy disk you've just created.
Type this command::
dmb Nom_Prg.mb

- If everything work fine, you should see on your pc screen:
Sending data. Please Wait...
CRC Ok - Done
you can now, disconnect your GBA from the cable.

- If an error occur during the transfert, the pc told you:
Sending data. Please Wait...
CRC Bad ! - Abort
try again the transfert without turning off the power the GBA.

- If you've made a mistake during the conception of your cable, or if it is badly connected to the pc, the message "Sending data. Please Wait..." will not be displayed on the pc screen.

3) The development Cartridge.

a- Where to get:

There are several supplier for the cartridge:

Lik-Sang : The most famous,
Succes Store : The cheapest (the cartridge doesn't have the same name, but is the same),
Lan Kwei Trading: cheapest than Lik-Sang.

b- Installation

### I don't have the cartridge, i don't know... :(((

c- To allow the compiled file running on a real GBA:

The compiled file can only be run on a real GBA if the CHECKSUM of the cartridge is valid.

For that, we have to use the file "Gbarm.exe" from "GBARM10.ZIP", witch can be downloaded from the "Credo'S Temporary Site".

To validate your rom (compiled file), you have to enter from a DOS prompt:
gbarm.exe -v name_of_file.bin
The file "name_of_file.bin" is modified. A valid checksum is created and written onto this file. You can now program this file on your development cartridge, and see the result on a real GBA.

In this tutorial, the compiled and executable file will have the extension ".GBA" (checksum OK), instead of ".BIN" witch is the extension for fresh compiled file.