Flashable TOSx4

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Flashable TOSx4

Postby popsel » Tue Jul 01, 2008 6:00 am

Built IN Overview 1.png

FLASHED TOS x4 Main top.png

Main TOP.png


This is a common project of Ppera and me (Popsel).

What is it for ?

Keep up to 4 TOSes in only 2 flash EEPROMs.
It works from TOS 1.0 to 2.06 without modification.
Select between TOSes with a single button, system is controlled by a single chip microcontroller (AVR).
Each time the button is pressed the next TOS is selected.
Two seconds after the last selection the actual selected TOS-Bank# is stored into the AVRs own EEPROM.
This means that the ST boots always with the last selected TOS.
The STs TOS-EPROMs are hardware write protected, controlled by the AVR.
Write protection can be disabled by pressing the button until the red LED begins flashing and enabled by pressing it again.
The LED is a duo LED. The LEDs color shows which TOS-BANK# is selected:
Bank #1= red, Bank #2= green, Bank#3 = yellow, Bank#4= LED is off
The STs EEPROMS can be programmed while the ST is running.
Therefore Ppera wrote his programmer software.
To prevent unwanted TOS-switching while using the ST I added a TOS-lock function.
If the TOS lock is active pressing the button has no effect.
Activate the TOS-lock by pressing the button while powering on the ST.
The lock state is shown via alternating red/green flashes of the LED.

Enough theory! I made 4 video clips to show how it works:




Part 4: TOS-LOCK

Here is all you need in one archive:
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Re: Flashable TOSx4

Postby ppera » Wed Jul 02, 2008 9:51 am

Just to add some notes:

This board is for all ST machines: 260ST, 520, 1040, Mega ST. By some revisions it may not fit - where original ROMs are under PSU.
Not for STE - different ROM address space, and no much sense - older TOS as 1.02, 1.04 works not on STE.
If using internal IDE adapter better is to do ROM logic with GAL (instead 2x 74xxx chips) - there is space in for...

TOS versions usable with project: 1.00, 1.02, 1.04, 2.05 (not recommended) , 2.06 . Kaos TOS, Magic , + ?
Not good: 1.06 - it is STE only.

In circuit programming on machines with only 512KB is not possible with current programming SW. But is possible - just need some small corrections - instead loading whole 256KB block for programming at once, by dividing it into 2x 128KB, and programming in 2 steps. Then it can be done with some 150KB free RAM, what should be case when load TOS 1.04 in RAM...


Re: Flashable TOSx4

Postby simbo » Wed Nov 10, 2010 3:56 pm

please add an accumulator based serial rs232 115k baud port to this design
i expect the use of a UNC5818AF and a simple micro controller like pic12F type
to allow for flow control as non atari bus controlled for external flash
the use of a simple pal to simulate the task this chip i made a dll and model for
that seems not to exist now atall and is hard to find

is needed for RT programming of the 040 flash ic as its 16 bit serial to parallel
i can provide a very detailed model
then its worth making !

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Re: Flashable TOSx4

Postby SofiST » Fri Jun 03, 2011 12:42 pm

If user is careful will never delete all ROM sections - and it is only case when will make machine dead - because then can not boot-up and programm in circuit.
Btw, Magic - ROM version works well too . Tested with versions 5 and 6.2 .

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