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A T O M - 1 5   v 1 . 6   -   A T O M B I O S   1 5 / 2 5 / 3 1   k H z   M o d d e r

WARNING!: THIS SOFTWARE IS EXPERIMENTAL. USE AT YOUR OWN RISK. THIS SOFTWARE HAS THE POTENTIAL OF LEAVING YOUR VIDEO CARD IN AN UNUSABLE STATE. Before you use this software, please make sure you understand the consequences of flashing a faulty or wrong BIOS to your video card. You WILL NOT be able to boot your system in order to restore the original BIOS. Usually you will need a PC which motherboard has TWO display card sockets and a second usable video card in order to be able to boot the system and flash the bricked display card back into its original state. Keep in mind that the motherboard's integrated GPU usually DO NOT serve this purpose because it's automatically disabled by the BIOS as soon as an AGP or PCI-e video card is plugged in. Always use the ORIGINAL BIOS image obtained from your physical card when using this program.

A T O M - 1 5   v 1 . 6   d o w n l o a d

O v e r v i e w

ATOM-15 is an experimental tool designed to customize the video output of ATI/AMD display cards based on the ATOMBIOS firmware (probably all models since the Radeon X800). It works by modifying the BIOS firmware in such a way that the output frequencies of all video modes are adjusted into the user's specified frequency ranges. Its purpose is to reduce the possibility of sending pontentially dangerous frequencies during the BIOS post and loading process of the operating system, when using these cards with standard resolution and multi-sync CRT monitors.

Bear in mind that the modifications applied to the firmware only operate during the BIOS post and the operating system loading process. Once the operating system device drivers take control of the display card it will behave exactly the same as any normal card. This means that you will need to use system specific methods in order to customize the video output from the operating system itself, provided these methods are available.

This is a research project. It has been possible thanks to the documentation publicly available in the Linux open source drivers (ATOMBIOS headers and hardware registers for the different asics).

A T O M - 1 5   u s a g e

ATOM-15 is quite simple to use. Simply open the bios image (*.bin or *.rom). If the BIOS format is recognized, the "Patch BIOS" button will become active. Now select your monitor operational ranges by ticking their corresponding checkboxes. Then press "Patch BIOS". If everything goes well, you will have a modified BIOS image (marked with the "-mod" suffix) ready to work.

You can select one, two, or three of the provided ranges, in order to match your monitor's capabilities. Keep in mind that ATOM-15 will always try to recalculate each BIOS' native mode into the range which results in a better picture quality, from the ranges you allow it to work with. For instance:

- If both 15 and 31 kHz ranges are selected, then 640 x 480 will be calculated in the 31 kHz range, to avoid using an interlaced mode.

- If both 25 and 31 kHz ranges are selected, then 1024 x 768 will be calculated in the 25 kHz range, as interlaced, to avoid requiring big black borders.

Besides, ATOM-15 will always readjust the vertical frequency so it falls within the 50-60 Hz range. This will prevent 31 kHz arcade monitors to go out of sync due to 400-line BIOS modes that have a native vertical frequency of 70 Hz although their horizontal frequency is 31 kHz.

For a detailed log of the BIOS native modes and how they're modified, use the "View log" button.

F l a s h   t o o l s

You will need third party software in order to obtain the BIOS from your display card, and to flash the modified BIOS back to the card. Your options are:

- ATIFlash: for MS-DOS. Download here. How-to here.
    1) Boot into MS-DOS from a bootable USB disk, with atiflash.exe in it.
    2) atiflash -s 0 bios.rom
    3) Reboot, into Windows and use atom-15.exe to patch the BIOS, put it in your USB disk.
    4) Boot again into MS-DOS.
    5) atiflash -p 0 bios-mod.rom
    6) Reboot
    * Make sure to use short names in MS-DOS (8 characters + 3 for extension).
    * Caution: "-p 0" and "-s 0" point to the first PCI device. Check this in case you have more than one video card installed.

- ATI Winflash: for Windows. Download here.
    1) cd C:\atiwinflash
    2) atiflash -s 0 bios.rom
    3) Use atom-15.exe to patch the BIOS.
    4) atiflash -p 0 bios-mod.rom
    5) Reboot
    * Caution: "-p 0" and "-s 0" point to the first PCI device. Check this in case you have more than one video card installed.

While ATI Winflash is very convenient, our preference is for ATIFlash (it requires creating an MS-DOS usb boot disk), because from MS-DOS you can test your patched BIOS before actually flashing it to the card, by means of "lbios", as explained below.

U s i n g   t h e   B I O S   l o a d e r   l b i o s . c o m

lbios.com is a simple BIOS loader. It loads a BIOS image into the system's RAM so it takes control of the video card instead of its own ROM BIOS. You can use this tool before actually flashing the patched BIOS to the video card, to reduce the chances of flashing your card with a faulty BIOS. It is not guaranteed however that a BIOS that works when loaded into the RAM won't leave your card unusable later when flashed to the actual hardware: you're warned. But definitely, if the system hangs after running lbios, then DO NOT flash the BIOS. The effects of lbios are not persistent, everything will be back to normal after restarting the system.

lbios must be run from MS-DOS command line:

   c:\lbios romname.rom

To actually do a proper testing of the patched BIOS, you'll need to switch to different video modes, both standard and VESA ones. For this task, I find this tool to be the most convenient.

U E F I   n o t e s

ATOM-15 is not guaranteed to work with UEFI bios. It may work as long as the UEFI code uses VESA modes. If this is the case, notice that probably UEFI will require the VESA mode 1024 x 768 to be available. This will be true if either the 25 or 31 kHz ranges are used.

Unfortunately 1024 x 768 is not possible for the 15 kHz range, so this mode is disabled when only the 15 kHz range is used. In this case, entering the UEFI setup will result in a black screen.

S o u r c e   c o d e

The full source code of this program for the PowerBASIC 10.04 compiler is available here.

Special thanks to Ves, Cools and ID4 for helping me testing this software.