LoZ AST Cartridge

So I made myself a Legend of Zelda Ancient Stone Tablets cartridge with 4x4MB TSOP's, 1 for each week. I wired up each /CE to a 74LS139 and connected a 74HC393 counter to the 74LS139 to select between the TSOP's by pressing the RESET button. My problem is it doesn't boot up in the same order on the different SNES systems I have tested. Is there anyway to get them all to boot in the same order? If not I'll probably just wind up mounting 4 small switches to the cartridge.


TSOP Boot Order on power up and then after each RESET press:

JPN Super Famicom older APU module motherboard 1,2,3,4
US SNES new onboard APU module motherboard 2,3,4,1
US SNES MINI 3,4,2,1
US FC16 GO 1,2,3,4

Here is how it is connected

I'm pretty certain that there is no reason to think that the '393 will power up with a predictable number in it when you power it on. Even if it is, there's also no reason to think that SNES/RESET will only clock the ↓CLOCK input exactly one time when it's being turned on.

You should probably use the '393s +RESET input for this: try using an RC on the +RESET input with time constant somewhere around 1/10th of a second. (5V—capacitor—'393 pin 2—resistor—ground)

Also, good practice: you should really tie the unused counter's inputs to power or ground.

Thanks for the tips, I'll try them out.

The cap and resistor did the trick, thank you.

How did you get the saves to work properly? AFAIK, that game requires the .srm file to be renamed in order to continue in the next rom when using emulators. Doesn't switching the rom on reset delete the previous SRAM save info when the new rom is loaded? And, if so, how do you continue on with your game?

The reason you rename is because they all use they same save file to record progress, end save of Week 1 is the start save of Week 2 and so on. The game autosaves every minute including during the end sequence of every week.

On my cartridge, if I play Week 1 for 20 minutes and power off, when I come back to it later my save file is fine. If I cycle ahead to Week 2 - Week 4, the save file becomes corrupted. If I complete Week 1 and cycle to Week 2 my save file is present with all my stuff from Week 1. If I play say 20 minutes of Week 2 and power off, when I power back on and cycle to Week 2 the save is fine. If I cycle ahead Week 3 - Week 4 it resets my save file to the beginning of Week 2, but with all my stuff from Week 1 preserved. If I complete Week 1 and try starting Week 1 again, I start with all my stuff, the counter back at 1:06, but if I save here it screws up the file for Week 2 so I have to erase Week 1 and start again.

I have a cartridge dumper so I was able to backup my saves for testing. Otherwise this would have taken MUCH longer. I've not finished Week 2 yet, I'll report back by the end of the weekend when I complete Week 2-4, hopefully.

Update: Each week follows the same behavior, as long as I don't cycle ahead, the saves are fine. It is playable from beginning to end. This game is intense the first time around since you are trying to beat the dungeons and find all the secrets all within the time limit. Once you memorize where stuff is it isn't so bad.

Here are a couple of other things I have noticed. If I am playing Week 1 and I beat both dungeons to get the tablets I can go around and find whatever I need in the overworld and let the timer run out. Now instead of starting Week 2 next, I can start Week 1 with the dungeons already beat and go around and collect the heart pieces or whatever else I missed. I simply let the timer run out again and it creates a new save with all the stuff I have now found and it carries over to the next Week. I can do this for each Week, sorta takes the fun away from the whole timer function though.

Also If I am playing say Week 4 and save my progress the next time I load Week 4 if I press start at the main screen but not to actually start my save file, just view it, then power off, my save is reset like I never started playing Week 4 (Week 1-3 completion is still there with all my stuff). It happens to the other weeks as well. If I press start at the start screen and press start to continue my game but decide to power it off once it is loaded, the save file remains intact. Finally if I am playing Week 2-4 and I press start on any of the weeks prior it also resets my progress on the current week I was playing and saving my progress on. So if I am playing Week 3 and have a save file, if I accidentally press start on Week 1,2, or 3 so that the main menu is activated it resets my Week 3 as if I did not start playing Week 3. Actually this happens if I let the whole demo play on a Week prior to the one I am currently playing also.

Enough rambling, the game was very fun to play through and very challenging. I cheated and used the walkthrough from gamefaqs whenever I got stuck though.

What game cart did you use for this?

Hi,

Please, could you tell the capacitor and the resistor values??

Thank you very much in advance

Hi dudes,

I answer to myself

http://en.wikipedia.org/wiki/RC_time_constant

Thanks

A single-resistor RC works for the power-on stability, but it's not sufficient for debouncing the SNES /RESET line (unless the reset switch is already debounced... which I suppose would make sense, but I don't have a schematic in front of me to confirm...). If you get it moving more than one slot each time you press the reset switch, you need a more robust debounce, like this

Hi,



Thank you very much for this, but I've done a simple multicart with some shooters using the method described above, the capacitor and the resistor, and it works ok, so it seems to be that the SNES/RESET could be debounced.

http://youtu.be/0I5g598O39I

Un saludo

EDIT: now the video works

What values did you use to make the cart stable? Cap and resistor.