EEPROM Substitution - AT24C1024B for the AT24C512B?

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RedLion
 
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EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by RedLion »

If it were readily available (which it doesn't seem to be, at least in a PDIP package), would it be feasable to substitute the AT24C1024B-PU25 for the 512Kb version?

I see from a quick check of the datasheet that pin1 is NC instead of A0, so it might not work if that pin is being used in the current design.

adafruit
 
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Post by adafruit »

you could but they box only uses 512 kib

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darco
 
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Post by darco »

Sounds like the chip is just two AT24C512B chips, one with A0 pulled high and the other with A1 pulled low.

If this is the case, then it should work fine.

bluej774
 
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Re: EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by bluej774 »

I, too, was interested in using an EEPROM with more memory than the included 64KB one. Has anyone successfully tried this? What's the largest one suitable?

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Re: EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by adafruit »

unfortunately it doesn't quite work that way. the ybox can only run code in its 32kb address space. if you put a larger eeprom in, you wouldnt get more RAM or bigger program space. instead you could only store additional data that the program would read

bluej774
 
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Re: EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by bluej774 »

I see that's a limitation of the Propeller chip, but wouldn't it be possible to engineer a solution similar to the XTREME 512K CARD for the HYDRA?

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Re: EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by adafruit »

sure, i dont know precisely what it is but if you can find the schematics... :)

bluej774
 
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Re: EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by bluej774 »

Basically, all it does is introduce a CPLD to act as a memory controller and shift the address space in 32Kb segments through the 512Kb of SRAM. At least that's my understanding of it. Here's what wikipedia says:
A 512K RAM memory expansion card, the HYDRA "XTREME 512K CARD", is available and can be plugged into the expansion connector. It has two memory segments, a 64K completely random-access segment, and a 448K linear accessible segment. During boot time the memory interface can be programmed to optionally auto-increment or decrement the memory pointer for faster memory access. But the interface is based on a reprogrammable CPLD chip, so the access method can be re-programmed to suit the application, but for most applications the chosen method is optimal for speed (for the 64K segment), and utility.

The memory expansion card also has its own 128KB EEPROM on board.
More details here and I was able to find a schematic for it. I'm sure a similar design can be adapted for the ybox2. I'm just not sure it could still fit in a mint tin. ;)

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Re: EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by adafruit »

ugh, it sounds like a significant amount of work. i doubt ill have time to do it but it -is- possible

bluej774
 
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Re: EEPROM Substitution - AT24C1024B for the AT24C512B?

Post by bluej774 »

Don't worry about it. It doesn't have to be any kind of priority. None of my widgets have come close to exceeding 32Kb yet. Once I need more ROM space, I'll take another look at it and play around with it. Just knowing it's possible is good enough for me. :D

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