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What does it mean that a chips has 8M x 16 bits memory?

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andrew257

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Hi all

if a chip has 8M x 16 bits what does this mean. If it simply said it can store up to 8Mb that would be fine but the x 16 is confussing me.

also from an application point of view, do you assume if a chip has a 23 bit address then it can store data from address 23'b0 to 23'b1.

thanks
 

Re: memory

8m x 16 bit = 8m x 2 x 8 bit = 16mbyte.

8m = 2 ^ 23 addresses.

to access individual bytes you will need extra byte enable bit.
 

Re: memory

shawndaking said:
8m x 16 bit = 8m x 2 x 8 bit = 16mbyte.

8m = 2 ^ 23 addresses.

to access individual bytes you will need extra byte enable bit.
Click to expand...


thanks for the fast reply, i was wondering about the 23 addresses becasue one source says [22:0] and another says it is a 24 bit address but the extra bit must be for individual bits. Thanks

why do they describe the memory as 8m x 16, and 8m x 2 x 8 is still confussing?
 

memory

"8Mx16" means 8 million words (23-bit address bus) and 16 bits per word (16-bit data bus). The total capacity is 128 million data bits.

Some memory devices can be reconfigured by connecting a mode pin high or low. For example, that 8Mx16 memory might be reconfigurable as a 16Mx8 memory. Then it would have 16 million words (24-bit address bus) and 8 bits per word (8-bit data bus). The total capacity is still 128 million data bits. Such reconfigurability allows one memory device to be useful in two different applications.
 

Re: memory

because this is how memory is orgenised.

althought most memories (all) will give you the oprotunity to keep working in byte mode., it is posible you will find some in which you can't - thus you will loose half your memory because address will be jumped by 2 byte each time you will access it.
 

Re: memory

do all memory addresses start from zero or do they start from address one. Only the board i am using has 24 bit address but address zero has no connection acording to the user manual. therefore its a 23 bit address starting from 1 and going to 23.
 

memory

You should read the device's datasheet to see how they've numbered the data and address bits. Don't assume that the numbering follows any convention. The Intel StrataFlash shown on page 14 has a mode pin (BYTE) that selects different data/address configurations.

This page has a link to the 28F128J3 datasheet. See its "Functional Overview" for a description of the BYTE and A0 signals.
https://www.intel.com/design/flash/support/retired/j3/
 

Re: memory

Hello,

8M X 16 means 8 mega locations of size 16 bits each.
Each locations can be accessed by a unique address and read write is possible, of course by giving proper control signals like RD, WR, REN, WEN and CE.
If you need more details, please don't hesitate to contact me. OK Bye

Regards,
N.Muralidhara
 

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