What I would need to know from anyone of you is if this problem also occurs on the CR version of the VIC-20 which has a different type of power supply. The CR generally has the same type of power supply as the commodore 64 and uses a round 7 pin DIN power supply connector.
This is the VIC I'm currently using, and it shows the same behaviour. Nevertheless, I wouldn't call it a *problem* - it's just an undocumented feature. It can be useful, for example as an alternative way for loading write-protect ROMs: load normally > reset > (fuzzy screen) > turn off the VIC > switch to READ ONLY > turn on the VIC (try it). Or - you can impress your less experienced friends with this kind of 'semi-volatile ROM', and so on. Not a problem anyhow.
Thomas Hechelhammer wrote:
There are two possible reasons:
1. The RAM cannot be used in the VIC PCB because it needs too much time loosing the stored information after removing the power. I'm only using RAMs of the KM-series which have no problems.
Unfortunately, this is not the origin of the problem. As Alan said, unplugging the cartridge does erase the content of its RAM.
I've contacted one of my hardware-developers in my company.
As I pointed out before, some S-RAMs keep the informations longer than they should; he talked about holding-times up to an hour.
In combination with the capacity of the whole thing, RAM expansion + VIC PCB.
The only thing I see is opening the BLK5 line with a switch while reset is pulled.
200 ms should be enough.
You could use a delay-line like the DS1000 which is connected to an analog-switch. The analog-switch controls the BLK5 line.
orion70 wrote:I wouldn't call it a *problem* - it's just an undocumented feature. ...Not a problem anyhow.
Well, if you see it as a feature then that's fine by me.
However, now that I am aware of this, all new expanders will have a standard wide 28 pin chip without data retention mode unless requested by the customer. There is no difference in price.
I am still looking for an easy solution that allows to purge the content of the memory without unplugging the expander.
I am still looking for an easy solution that allows to purge the content of the memory without unplugging the expander.
Maybe I found one. Turn off the VIC; hold down the reset button for about 10 seconds; turn on the VIC; release the button. At least, it works with my VIC - don't know if it can be useful for others.
If this sequence can somehow damage the computer, please tell me before it's too late
orion70 wrote:Maybe I found one. Turn off the VIC; hold down the reset button for about 10 seconds; turn on the VIC; release the button. At least, it works with my VIC - don't know if it can be useful for others.
If this sequence can somehow damage the computer, please tell me before it's too late
I really don't see how holding a button on the VIC while it is off can damage it but it proves something I suspected. Power comes into the VIC from the serial port. If your drive or anything is connected to the serial and turned on, the reset line has to be high... it's a source of 5V...
That's the source of the problem I suspect the most.
Disconnecting the serial port or turning off whatever is connected to it should do the job.
The expander was shown at the WoC... I'm sorry, I have to say I only got 2 orders...
Sorry to hear that after the loooong trip without any sleep
Any options/ideas of configurations for that Super Game Expander we discussed at WOC and Leif volunteering to do the menu for such?
I think 16K games from tape would be my option to cut on load times. With a 5 card slot switching between games is easy enough for me for carts. But a "Best of carts" could be interesting too
Centallica wrote:
Any options/ideas of configurations for that Super Game Expander we discussed at WOC and Leif volunteering to do the menu for such?
From a hardware point of view, I know exactly what to do to. However, apart from KilrPilr and, perhaps you, nobody seems interested in buying such a cart.
To make it worthwhile, a multicart for the VIC would have to be produced in at least 50 units and I really doubt I could ever sell half a dozen of them...
well i have the eproms and the lsxxx chips to make them now. One day it will come togther. Just need someone with energy and knowhow to put it together.
Surprisingly, I got two people to buy my games. I think you'd get more buyers than you expect. Unless everyone is still holding out for the mythical "flash cart".
I think he would get more buyers than he thinks too Jeff, well unless he asks like $200 or $300 for the cart. If a person asks like $75 or $100, i think he would sell at least 50 easily and im sure alot more if they were offered up on ebay or a decently designed website.
well, he is basing his assumption on the fact that while 40 people said they liked his vic expander, only 2 bought one. instead of recognizing that it is VERY useful, people just sit and talk and not buy
get 40 preorders prepaid and he'll probably make it. its the same reason i didnt make the diag carts. poeple were wanting to pay less than it cost me to make them.
