Tickled_Pink's Blog - Loop Removal and Hardware considerations

RSS Bot · October 19, 2007

Finally got around to finishing the main elements of the game. Still some work to do, though. Just got the loop highlighting and removal working. The TODO list now consists of:

1. Get scoreboard working.

2. Add incomplete loop removal widget.

3. Fix edge placement bug. The original loopz doesn't allow players to place a shape's open end up against the border of the grid. XNA Loopz doesn't either ... it just goes off into an infinite loop. :roll:

4. Get completed loopz counter working.

5. Rewrite the random shape generator. Doesn't play particularly well at the minute because it tends to bring up the same shapes too often.

6. Re-record ST or Amiga game music and get it working. (Maybe)

7. Add sound effects. (Maybe)

The A8 version will be ROM based. I've been delving into my parts boxes. I've got plenty of EPROMS and a Willem burner, plus a few Flash ROMs. However, the original plan was to have a cart onto which you could save your high scores. Flash was a possibility. The only things I didn't like about Flash was its relatively slow write access speeds, and the fact that most Flash ROMs (all of those I looked at, in fact) required you to write in blocks of memory - reminded me of the wastage from DOS3!

Another idea was to ship carts with the standard EPROM or Flash to hold the game, but then piggy-back a nonvolatile SRAM to the cartridge's board. That's why I got hold of a couple of 1K Dallas battery backed SRAMs. But they are bloody huge lumps! There may be a better solution.

I also have a couple pieces of Simtek 32Kbyte nvSRAM that don't require a battery - either internal (like the Dallas) or external. These are very interesting pieces of hardware in that they effectively contain two types of RAM in one IC. When the power is switched on, the device acts like RAM and you can read and write to it at will. As soon as the power is switched off, however, internal capacitors keep the thing running long enough for the data in RAM to be moved to its internal EEPROM store. So when the power is switched back on again, whatever's in the EEPROM is copied back into RAM.

My only concern would be accidental overwriting of the game. I'll have to go through the datasheets to find out if there's any way of preventing writes to certain blocks of addresses. If not, I can still use the ROM + RAM approach. Another problem with using the Dallas is that once the battery runs out, you're out of luck. With the Simtek, your data's always there.

I had a quick scan through the datasheets earlier and found something that would be interesting to anyone who wants SpartaDOS X and the R-Time cart but can't find one. There is a version of the Simtek nvSRAMs which come complete with an RTC built-in. It doesn't even need a battery to keep the clock running if you use it frequently. By adding a capacitor, you can keep the clock running for up to 30 days! SpartaDOS would need to be modified, for sure, but it might be a worthwhile project for someone.

http://www.atariage.com/forums/index.php?a...;showentry=4043