DRAM

[dogdens_R]

Hi,

does anyone know when refreshing a DRAM, does ALL its banks get refreshed at once or can we control individual bank refresh?

i know infineon's 1Gb ddr2 sdram datasheet explicitly states that all its banks have to be idle when applying the refresh command but i was hoping that other manufacturers have included an individual bank refresh feature.

micron's 512Mb ddr2 sdram datasheet doesnt really state clearly and i dun wana assume....

thanks

 

[shamikrudra]

Hi,

does anyone know when refreshing a DRAM, does ALL its banks get refreshed at once or can we control individual bank refresh?

i know infineon's 1Gb ddr2 sdram datasheet explicitly states that all its banks have to be idle when applying the refresh command but i was hoping that other manufacturers have included an individual bank refresh feature.

micron's 512Mb ddr2 sdram datasheet doesnt really state clearly and i dun wana assume....

thanks

i dont think it is posible
b cos all the manufacturer making with same topology

 

[tansis]

Are you building a "hyper-drive" or solid state hard disk by any chance?

 

[Roff]

Micron Technical Note TN-47-16 includes a discussion of refresh timing. I think the answer is, you do not have to do all the refresh at once.

 

[dogdens_R]

Are you building a "hyper-drive" or solid state hard disk by any chance?

nope.. sorry.. i m trying to find a way to store data coming in at 500MHz with a 32-bit wide data width. i suppose a 267MHz ddr2 sdram would suffice?

i was hoping that banks can be individually refreshed so i can avoid having to buffer a lot of data.

 

[dogdens_R]

Micron Technical Note TN-47-16 includes a discussion of refresh timing. I think the answer is, you do not have to do all the refresh at once.

yeah but it doesnt say if we can control which bank to refresh.. or when we give the refresh command, it will only refresh banks that are not precharged (closed). so i can leave the banks that i do not want refreshed open?

has anyone attempted interleaving write and refresh commands to achieve 100% thru put?