Query Reg. the External Flash support considerations for an MCU.

[madhu.wesly01]

Hi,

I am trying to add an external SPI Flash memory as a data logger on my PCB to save GPS data. Could you please suggest me the major considerations to be followed while selecting the SPI flash memory? Will there be a constraint like a MCU(ATSAMD21G18A) can support up-to a specific size of flash memory and so? In my case, it is not given that how much external flash memory this ATSAMD21G18A can support.

Will the MCU(ATSAMD21G18A) support 16MB, 32MB, and 64MB Flash memories?

Could anyone please share knowledge in this regard.

Awaiting your reply.

Thanks & regards,
Madhuwesly.

[ealex]

there is no inherent limit on the external SPI flash size.
your code will be the only limit - the SPI peripheral and the memory will just do what it's told to.

you'll have to carefully read the memory datasheet and write your "driver" accordingly
just be careful on some specific implementation: minimum erase page size and some specific behavior.

for example you can have different behavior when you write several bytes at once an you're not aligned to a page boundary.
some devices will wrap at the start of a 256 bytes page and destroy previous data, other might move to the next 256 bytes page or ignore data that's over the page boundary until the next write command