Kickflash OS4 is a plain ROM card for Amigas with Zorro slots. It contains two 512K Flash memory chips and an 8-bit expansion port compatible with the pin header of the A1200 mainboard, also known as the "Clockport".
You can write any version of kickstart into that memory and have it available after the next reboot. Flash memory is non-volatile, that means, it doesn't loose it's contents when power is switched off. On the other hand, it's electrically erasable. As soon as the new Kickstart V3.5 is available, you're the first one to have it as a rom. It has already been announced that nobody will produce mask roms of Kick 3.5, so Kickflash is your only chance to get rid of the inconvenient reboot for re-kicking the new rom. Besides, re-kicking uses memory, and Kickflash does not, so you can use your fastmem for more important things.
You can also use Kickflash to make your computer compatible with old software by programming Kickstart V1.3 or 2.0 into the flash - it's up to you, there's no limits.
If something should go wrong while "flashing" a new version (power failure, computer crashes), don't panic! Just switch back to your rom, and the computer will start normally. Even when the switch is set to "rom" instead of "flash", the flash can be written and verified. The operation just takes a few seconds. For protection against viruses, the flash memory can be write-protected.
As with all our products, the installation is very easy: Remove the kickstart roms, place Kickflash into the empty sockets, and insert the roms into the sockets on the Kickflash. Additional connections are not necessary!
64K config space vendor ID: $1212 (4626) product ID: $0a (10) serial ID: 0 RomdiagVec: $8000 (if valid, see jumper setting)
The rom diagvector is set valid/invalid with the jumper. The jumper also write-protects the flashrom, so it cannot be altered accidently.
Jumper open: diagvec is valid, and writes to the flashrom are inhibited
Jumper close: diagvec is invalid, writes to the flash chip are enabled
If writes are inhibited, they're inhibited by hardware. There is no software trick to access the flash without the user really enabling it with the corresponding jumper setting.
Kickflash OS4 is a pure 8-bit card. Only even addresses are used. Odd addresses contain random data. Writing to odd addresses will garble the contents of the even address below it, so this is not recommended.
config nibbles (changing with jumper setting)
Flashbank register for Flashrom 0 (bits 7 downto 3. 2, 1 and 0 unused)
Flashbank register for Flashrom 1 (bits 7 downto 3. 2, 1 and 0 unused)
clockport activation register
mirror of $0078
One of three memory spaces:
Flash chip 0, flash chip 1 or the clockport are mapped here. If one of the flash chips is selected, 16K are mapped in here. Select one of the 32 banks of each chip by writing the number of the bank to the corresponding register, shifted 3 bits to the left (lower 3 bits are unused!).
using the clockport
The clockport is selected by writing any number to the clockport activation register. The spare_chip select area is available at offset $8000. Most clockport expansions use this select-signal.
In that mode, the RTC_chip select area is available at offset $a000. Only real clock modules for the clockport use this signal, such as the RTC module by iComp.
After a reset, bank 0 of flash chip 0 is active. Activating the other flashrom or the clockport will deactivate the other two possibilities.
Please consult the AMD 29f040 document to get information about programming the flashrom.