Which Flash Memory to use for cart conversion

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snezzdev
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Which Flash Memory to use for cart conversion

Post by snezzdev » Tue Mar 17, 2020 4:56 am

Hi. I want to convert couple games like Legend of Zelda and Chrono Trigger to English. Im going to replace ROM memory with flash memory. Reading articles in internet i saw people use 29F032 flash chips. But this one is huge and a bit pricy. So im wondering if there is smaller and cheaper alternatives ? 64Kbyte should be enough for all games ?

lidnariq
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Re: Which Flash Memory to use for cart conversion

Post by lidnariq » Tue Mar 17, 2020 10:24 am

snezzdev wrote:
Tue Mar 17, 2020 4:56 am
64Kbyte should be enough for all games ?
... are you trolling???
64KByte isn't even enough for most NES games, let alone any SNES games.

The largest suitable (5V) new flash being made is 512KB, which is enough for a very small handful of SNES games - about 10%.

Otherwise, you're stuck buying New Old Stock, part pulls, or adding voltage translation parts.

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TmEE
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Re: Which Flash Memory to use for cart conversion

Post by TmEE » Tue Mar 17, 2020 10:45 am

Alliance makes new 5V 2MByte sized parts but they are pretty expensive for the time being.

snezzdev
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Re: Which Flash Memory to use for cart conversion

Post by snezzdev » Tue Mar 17, 2020 11:14 am

How about MX29LV320AB ? 32Mbit and cheap. Possible to use ?

lidnariq
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Re: Which Flash Memory to use for cart conversion

Post by lidnariq » Tue Mar 17, 2020 11:17 am

Not without adding extra parts.

That's a 3V part, and you must add 5V translation ICs to safely use it in a SNES.

snezzdev
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Re: Which Flash Memory to use for cart conversion

Post by snezzdev » Tue Mar 17, 2020 11:59 pm

Can you give advice what memory to use ?

lidnariq
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Re: Which Flash Memory to use for cart conversion

Post by lidnariq » Wed Mar 18, 2020 12:23 am

As stated, you don't have a lot of choices.

You can use New Old Stock or part pulls. Most of the 5V flash is expensive by now. The older CDIP UVEPROMs are relatively affordable but the 4MB 27C322 specifically requires support hardware. The 27C160 can be used as-is. Be careful of parts damaged by the salvage process and be prepared to accept some lemons.

You can use 3V flash plus all of the voltage translation hardware. The SNES is a 5VCMOS device so you must translate the voltage up from the 3-ish V that the flash runs at to 5-ish V for the SNES or else it may randomly crash. There are a bunch of options for up- and down- translation; both are non-negotiable.

(You can pay a premium for Alliance's new 2MB SMT flash).

You can one or two 512KB flash (SST39SF040) for games that are 512K or 1M in size. This is more-or-less your only option if you insist on using donors, as these are the only parts that are affordable and even close to fit-and-form compatible, only gets you 512K games with battery backup, and 1MB games have to start from rare YA0N or YJ0N boards. A new PCB without donors is really a better choice.

snezzdev
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Re: Which Flash Memory to use for cart conversion

Post by snezzdev » Wed Mar 18, 2020 9:21 am

Thank you for answer. Here is video https://www.youtube.com/watch?v=d-CjiHZ ... 6562181300
This guy using 3V flash. He says it works fine. He only used supply voltage converter, but data lines works without conversion.
Ill try same approach. Will see how it works.

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poorstudenthobbyist
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Re: Which Flash Memory to use for cart conversion

Post by poorstudenthobbyist » Wed Mar 18, 2020 9:29 am

No! 3.3V parts (flash) in a 5V system (SNES) is BAD! That extra power has to go somewhere and, while it might work initially, you can slowly kill your system.

viewtopic.php?f=9&t=16213

Ice Man
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Re: Which Flash Memory to use for cart conversion

Post by Ice Man » Wed Mar 18, 2020 9:41 am

That's a cheap solution to use only AMS1117 and while it does work it is not recommended as it can damage the chip since the address lines are stil fed with 5V. Proper voltage translation is the key e.g. 74LVC245A.

lidnariq
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Re: Which Flash Memory to use for cart conversion

Post by lidnariq » Wed Mar 18, 2020 10:27 am

Do not connect a 3V part to a SNES without explicit parts for translation. It will damage the SNES, and it will damage the flash part.

The latter is replaceable, but you cannot fix a SNES you break.

snezzdev
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Re: Which Flash Memory to use for cart conversion

Post by snezzdev » Wed Mar 18, 2020 10:32 am

Does that mean Benn Venn here is wrong ? https://www.youtube.com/watch?v=vv4TeyLcSSw

snezzdev
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Re: Which Flash Memory to use for cart conversion

Post by snezzdev » Wed Mar 18, 2020 10:40 am

Ice Man wrote:
Wed Mar 18, 2020 9:41 am
That's a cheap solution to use only AMS1117 and while it does work it is not recommended as it can damage the chip since the address lines are stil fed with 5V. Proper voltage translation is the key e.g. 74LVC245A.
If i going to use MX29LV640 where 22 address and 16 data lines which is 38 in total i will need 5 of 74LVC245A, is that correct ?

Markfrizb
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Re: Which Flash Memory to use for cart conversion

Post by Markfrizb » Wed Mar 18, 2020 10:51 am

snezzdev wrote:
Wed Mar 18, 2020 10:32 am
Does that mean Benn Venn here is wrong ? https://www.youtube.com/watch?v=vv4TeyLcSSw
Well.... it's hard to say...... His video is assuming the flash chips can still be safely powered by 4.6v, which in most data sheets for the available flash roms, is beyond normal safe operating conditions.... MOST 3v parts operate at 3.3v, with 3.6 being the safe maximum.... and some chips allow an tolerance of .5v over or under. That would be 4.1v as an absolute max, which is riding the razors edge of safe or reliable operation and well below the 4.6v Benn is showing as "safe".
That's my understanding of it anyway...
If i going to use MX29LV640 where 22 address and 16 data lines which is 38 in total i will need 5 of 74LVC245A, is that correct ?
don't forget about the control lines too. They also need translating...

snezzdev
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Re: Which Flash Memory to use for cart conversion

Post by snezzdev » Wed Mar 18, 2020 11:19 am

BTW since flash works as ROM here data will be directed only one way, which means no need to convert data lines, isnt it ?

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