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 1: OVERVIEWhttp://de.youtube.com/watch?v=zFxkrliiIEs
Part 2: REPLACING A TOShttp://de.youtube.com/watch?v=tzHYh1bKUfM
Part 3: REPROGRAMMING A DEAD/UNUSED TOS BANKhttp://de.youtube.com/watch?v=yc0P7MuNGbY
Part 4: TOS-LOCKhttp://de.youtube.com/watch?v=z_qCmhf1bE8
Here is all you need in one archive:
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