bwinkel67 wrote:Marcel, had a quick question. Looking at the QL schematic for the ZX8302, it seems that pin 40 is getting 5 volts but my little board uses a 3 voly CR2032. Since my little board replaces the pin 40 input for the ZX8302, how come it still works? Is pin 40 the only voltage input to the ZX8302 (I see that pin 11 is also getting it and the board does seem to make a connection with that as well, though it still gets connected through the socket so I guess it's getting voltage from both?!?)...couldn't find a pin out sheet for it to see what the pins are for.
The chip is powered through pin 11, pin 40 is a dedicated battery input that only powers the clock inside the chip.
Just curious what the little board is doing. Does it basically replace the QL's power with the button cell for the ZX8302 and then power the chip 24/7? If the button cell runs out of power, I'm guessing in that instance the QL stops working until I replace the battery. Also, one reason I ask is, since these chips are so rare, is it a good idea to power them indefinitely vs when you use the machine?
When the button cell runs out of power I guess your clock might stop ticking, but the chip should continue to work. I've never had a ZX8302 die on me, I wouldn't worry too much about it. The ZX8301 is much more problematic, I've got a graveyard of those.
By the way, there are much better re-created schematics like
http://www.dilwyn.me.uk/docs/hardware/QLissue6.pdf which even fix some errors on the original.