Beginner: Softune / start.asm / bus mode

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Hello experts,

just doing my first steps in development for Fujitsu MB90F345 using
Softune. The basic problem is: how do I tell the chip to run in single
chip mode? I know about the pins MD0, MD1 and MD2, but the manuals
mention some data in memory called mode data, and the bit format of
this is documented. But I don't know how to write this mode data into

As far as I have understood, there is some option "BUSMODE" for the
compiler or in the file start.asm. But in the compiler docs, no such
option is mentioned, and I don't know how to use this option within

So could anyone tell me how to use the busmode option within
start.asm? Any example code? I would also be interested in a link to
the manual where this is documented...

Thank you very much!


Re: Beginner: Softune / start.asm / bus mode
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Hi, in the startup file you should see a section (4.8) "external bus
interface". There are some set instructions, the 4th one should say:- set
busmode single_chip. The mode data is stored above the reset vector, the
compiler puts it there for you, and the processor reads it in automaticaly at
reset. Make sure the mode pins are correct.

Re: Beginner: Softune / start.asm / bus mode (CBarn24050) wrote in message
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Then, my installation of Softune must be incomplete. After a fresh
install of 3.5,  there are some files with the name pattern start*.asm
in the "sample" and "lib" directory of the Softune installation,
basically all with similar contents. There is no file with section
numbers and no file with the content you mentioned. So please, if I
may you bother again: how is the exact name of the startup file, and
where is the exact location (relative to the softune installation or
the project directory)? And how do I "activate" it?

I even greped my whole harddrive for files with the word "busmode",
but no results! So it's definitely not there...

Thanks again,


Re: Beginner: Softune / start.asm / bus mode
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Hi, I have an earlier version than you. If you look in the sample dir you
should find start.asm or something similar. Bring it up on the editor and look
for the bus control section it should be self explanatory. If not you could try
inserting the line SET MODEBYTE 0  Modebyte sould be difined in the .h files
and .asm files for your chip. After you compile you can check address ffffdf is
should be 00 for single chip operation.

Re: Beginner: Softune / start.asm / bus mode - SOLVED (CBarn24050) wrote in message
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Thanks again for your help! I've identified the problem in the
meantime: A few days ago, when we tried to get Softune, we were in a
great hurry; so, instead of waiting for the CDs, we convinced someone
to mail us the installation archive before the CDs reached us. Then we
installed from the archive we got by mail and did a few tests; but
unfortunately, this archive did not include the samples with the right
start.asm. Yesterday, we got the CDs, and behold: There is an extra
installation archive for many more samples on the CDs, with the right
start.asm. So I suppose I will be happy (busy) on the next days.

By the way, it will be Fujitsu's secret forever why they put the
software in the "PDF" directory of their CDs...

CBarn24050, your tips were a great help because you confirmed what I
had to hunt for... All the start.asm, startup options, and the
relationship between C compiler and assembler is a little bit
confusing if you are used only to a simple AVR AT90S8515 ...

Yours sincerely,


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