FLASH memory - quick fundamental questions

Thread Starter

robotDR

Joined Mar 17, 2020
3
I am needing to find an alternate flash memory module and have a couple of quick questions:

If referring to digikey product specs: (take this for example: https://www.digikey.com/products/en?keywords=MX25U12835FZNI-10G )

1) Can I get an alternate part with a faster clock frequency? The current one is 104 MHz, can I get one with say 120 MHz or will firmware need updating?
2) Can I get an alternate part with more memory, like 256Mb? Or will this require change to firmware?
3) Are address registers usually the same? Or will a change from one manufacturer to another require a change to firmware for addressing?

I'm trying to find an alternate for the part listed above. Need to keep the same footprint and pinout.

I found this one:
https://www.digikey.com/product-detail/en/gigadevice-semiconductor-hk-limited/GD25LQ128DWIGR/1970-1056-1-ND/9484805

But it has a faster clock frequency. And maybe the addressing is different in firmware?

Thank you for your time.
 

Papabravo

Joined Feb 24, 2006
14,393
When you say changes to firmware for an SPI flash module the answer is probably yes if you want to take advantage of faster clock speed or greater capacity. However it might not be that simple. Let us say that you get the faster parts and discover that the PC board traces are to long for SCLK to work at 120 MHz. You get killed by reflections and you have to redo your PCB. This is a much bigger deal than a firmware change. When it comes to addressing and data transfer you may or may not have to make a firmware change. This is not an easy question to answer without access to more information.
 

Thread Starter

robotDR

Joined Mar 17, 2020
3
When you say changes to firmware for an SPI flash module the answer is probably yes if you want to take advantage of faster clock speed or greater capacity. However it might not be that simple. Let us say that you get the faster parts and discover that the PC board traces are to long for SCLK to work at 120 MHz. You get killed by reflections and you have to redo your PCB. This is a much bigger deal than a firmware change. When it comes to addressing and data transfer you may or may not have to make a firmware change. This is not an easy question to answer without access to more information.
Hi Papabravo, thank you for your reply.

I dont want to use the extra memory or speed. I just want to replace the out of stock part with something that has equal or better stats.

The board is already in FAB, and the fab house said they can't find the flash memory chip at distributors. So I'm looking for an alternate.

I wont be changing the speed. I'm just curious is 120mhz a max speed? Or does firmware need to change because the memory chip only operates at 120mhz?

The chip before this (out of stock) is a 104 MHZ chip. Is that max speed? If so, couldn't I just swap out for 120mhz and the firmware/micro and simply not use that extra speed? I don't need 120mhz, i want to keep everything the same, just change the model number of the flash memory to something that will fit on the board and work with current firmware.

Same with memory size. Does anything need to change in the firmware to reflect bigger memory?

Thank you for your time!
 

Papabravo

Joined Feb 24, 2006
14,393
Hi Papabravo, thank you for your reply.

I dont want to use the extra memory or speed. I just want to replace the out of stock part with something that has equal or better stats.

The board is already in FAB, and the fab house said they can't find the flash memory chip at distributors. So I'm looking for an alternate.

I wont be changing the speed. I'm just curious is 120mhz a max speed? Or does firmware need to change because the memory chip only operates at 120mhz?

The chip before this (out of stock) is a 104 MHZ chip. Is that max speed? If so, couldn't I just swap out for 120mhz and the firmware/micro and simply not use that extra speed? I don't need 120mhz, i want to keep everything the same, just change the model number of the flash memory to something that will fit on the board and work with current firmware.

Same with memory size. Does anything need to change in the firmware to reflect bigger memory?

Thank you for your time!
SPI can run at ANY speed determined by the master. As long as the memory device can handle the speed everything should be fine.
Don't know about the extra capacity. Whatever replacement you get your going to want to make sure that it will provide the space you need without firmware changes. The simple test would be if the additional address bits are already part of the address which is transferred to the chip and are set to zero then you should be OK
 

Thread Starter

robotDR

Joined Mar 17, 2020
3
SPI can run at ANY speed determined by the master. As long as the memory device can handle the speed everything should be fine.
Don't know about the extra capacity. Whatever replacement you get your going to want to make sure that it will provide the space you need without firmware changes. The simple test would be if the additional address bits are already part of the address which is transferred to the chip and are set to zero then you should be OK
Ok great, that info about the speed helps a bunch.

I have been looking over the datasheets for both parts I referenced in my first post.
Their commands for everything seem to match perfectly. I haven't gone over every command yet, but they seem to be completely identical.

I guess i just have to make sure that the address to different memory sectors is the same. I have very little experience with flash memory chips.

Thanks for your help!
 
Top