Fully non-volatile version of the Ultimate Expander

[eslapion]

Hello everyone.

Since 2006 now, I have been selling the Ultimate Expander for the VIC-20.

In its early days, it was discovered that the chips I used on the UE had a data retention mode and that the small amount of power that trickled back into the VIC when it was turned off with 1541 or other drive turned on and attached to the serial port would keep the data in the expander from being erased.

This had inconvenient effects when a game had been placed in the BLK5 RAM area as there was no way to prevent the game from starting other than unplugging the cart from the VIC. However, some people did mention they liked the idea of having a non-volatile UE.

I have recently been informed of the existence of RAM chips that not only do not lose their content when power is turned off, they also do not use a battery to achieve this and can keep their content in excess of 45 years.

This is the type of RAM chip: http://www.ramtron.com/files/datasheets ... s_r3.4.pdf

I can therefore offer a fully non-volatile version of the Ultimate Expander that will keep whatever information you have put in it indefinitely.

In order to avoid the problem that can be associated with having something in BLK5, these version of the expander will always come with a switch to bypass the RAM's content in BLK5.

Also, people who expect the Non-Volatile Ultimate Expander to keep Basic programs should be aware that the VIC-20 normally uses the RAM in the VIC as storage for the early part of all basic programs. Therefore it is not normally possible to keep a Basic program from being erased.

However, it should be possible with a series of pokes to force the VIC to store all Basic program information in the expanded area. And a very simple series of commands should be used to retrieve this information when you power back up.

Also, adding ROM options to the NV UE is still possible but you should consider that what you put in BLK5 now has to be used to prevent accidental autostarting of the program you have placed in the NVRAM's BLK5. For this reason, unless you really know what you're doing, putting a game in there is not a good idea.

Tell me what you think of a Non-Volatile Ultimate Expander.

I consider selling it for 50$ plus the price of ROM options.

The standard Ultimate Expander sells for 30$ plus price of ROM options.

[carlsson]

I already have a non-volatile 8K memory expansion, switchable between BLK3 and BLK5 if I understood correctly. Perfect for games which store high scores in RAM to keep them intact even after power off.

[eslapion]

I already have a non-volatile 8K memory expansion, switchable between BLK3 and BLK5 if I understood correctly. Perfect for games which store high scores in RAM to keep them intact even after power off.

The UE is a 32k expansion and therefore can keep a lot more than just your score.

Having the whole thing non volatile is nice if you work on a new program or game and make changes often while not having to worry about saving what you've done so far in case of power outage.

Also, not having to save often can save a lot of time.