Adding sram to laser invasion

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lidnariq
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Re: Adding sram to laser invasion

Post by lidnariq » Sun Jun 30, 2019 3:09 pm

You can graft two RAMs on top of the PRG ROM as easily as anything else. It's not like that rework is the hard part.

Frankym2612
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Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 3:12 pm

I made an adapter that solders onto the cart and doubles as the prg rewire and it’s just big enough for one ram chip

Frankym2612
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Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 5:19 pm

I’m wondering if it’s my battery circuit not working then game works but won’t save. Here is exactly how I have it wired:

Pin 56 of mmc5 goes to pin 28 of ram
Pin 57 goes to a 1k resistor to the batteries positive then to pin 28 of the ram
Pin 93 goes to pin 28 of ram

lidnariq
Posts: 8690
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: Adding sram to laser invasion

Post by lidnariq » Sun Jun 30, 2019 5:26 pm

Frankym2612 wrote:Pin 56 of mmc5 goes to pin 28 of ram
As far as I know, that's how the normal circuit works, that's fine.
Pin 57 goes to a 1k resistor to the batteries positive then to pin 28 of the ram
But you already connected RAM Vcc to the supply on pin 56. Why did you connect it to the battery also?
Pin 93 goes to pin 28 of ram
Why did you do that?

Frankym2612
Posts: 34
Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 5:30 pm

For some reason if I don’t go from 57 to the battery and to the ram it glitches I tried just having 56 to 28, also the case with 93 I figured it needed to be tied high also tried tying it low it only works tied high

lidnariq
Posts: 8690
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: Adding sram to laser invasion

Post by lidnariq » Sun Jun 30, 2019 5:59 pm

Frankym2612 wrote:For some reason if I don’t go from 57 to the battery and to the ram it glitches I tried just having 56 to 28,
You've got some other problem going on then. The OEM carts aren't doing anything fancier.
also the case with 93 I figured it needed to be tied high also tried tying it low it only works tied high
Why did you assume that pin 93 should be tied high or low?

Frankym2612
Posts: 34
Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 6:13 pm

I’ve definitely got something going on although using laser invasion 57 isn’t going to a ram like in the koe carts. For the 93 it is a15 and there is no a15 on the ram chip I figured it was high disable low enable there are no other accessible pins on the ram but maybe you could fill me in on where it goes? I assure you Ille understand

lidnariq
Posts: 8690
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: Adding sram to laser invasion

Post by lidnariq » Sun Jun 30, 2019 6:28 pm

Frankym2612 wrote:there is no a15 on the ram chip
You're right. There isn't.

The ETROM PCB ignores A13 and A14, and instead only uses PRG RAM 0 /CE and PRG RAM 1 /CE.

Frankym2612
Posts: 34
Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 6:34 pm

Ok so I’m guessing use pin 26?

lidnariq
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Location: Seattle

Re: Adding sram to laser invasion

Post by lidnariq » Sun Jun 30, 2019 6:45 pm

Tell me what you're thinking. Why are you suggesting that?

Frankym2612
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Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 6:47 pm

You told me it needs to be connected to the ram

lidnariq
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Re: Adding sram to laser invasion

Post by lidnariq » Sun Jun 30, 2019 6:56 pm

And I'm asking you to explain your thinking process.

Frankym2612
Posts: 34
Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 6:59 pm

I don’t need to explain myself to you either you help me or don’t get off your high horse and stop playing these games

lidnariq
Posts: 8690
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: Adding sram to laser invasion

Post by lidnariq » Sun Jun 30, 2019 7:03 pm

I teach. I never give instructions that can be followed without thinking. If that doesn't work for you, have fun without me.

Frankym2612
Posts: 34
Joined: Thu Jun 27, 2019 8:25 pm

Re: Adding sram to laser invasion

Post by Frankym2612 » Sun Jun 30, 2019 7:08 pm

Oh I will

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