topic What is the maximum memory supported by T4240 and T2080 in QorIQ

What is the maximum memory supported by T4240 and T2080

siderealNight — Tue, 04 Jan 2022 21:18:26 GMT

The T4240 has 1 TB address space. Does that mean you can support up to 3 TB RAM?

What is the the maximum value for T2080?

thank you

Re: What is the maximum memory supported by T4240 and T2080

Bulat — Mon, 10 Jan 2022 05:05:03 GMT

There are some restrictions of course. When you ask "...can support up to 3 TB RAM?", you probably mean RAM like DDR? Here the T4240 is not a bottleneck, problem is rather with the RAM itself.

The T4240 supports DDR3/L memory and contains three DDR controllers with four memory banks (Chip Selects) each. In turn the the maximum volume of DDR3L devices is 8Gb. Assuming the user uses x4 devices and 64-bit bus width, the number of devices per one Chip Select is 16 pieces, that is 16 x 8Gb = 16GBytes. For Chip Selects provide 4 x 16GBytes = 64GBytes. So three DDR controllers can support maximum 3 x 64GByes = 192Gbytes, that is maximum supported DDR size.

The T2080 supports only x8 and x16 device organization, so in maximum it supports 8 x 8Gb =8GBytes per one CS and 4 x 8Gbytes = 32Gbytes per the DDR controller, i.e. per the T2080.

These numbers can be found in the Ref Manuals, see sections 'Supported DDR SDRAM Organizations' .

Regards,

Bulat

Re: What is the maximum memory supported by T4240 and T2080

siderealNight — Mon, 10 Jan 2022 21:34:00 GMT

Hi, thanks

" Chip Select is 16 pieces, that is 16 x 8Gb = 16GBytes. "

Should that not be 128 GB? , leading to 3 * 4* 128 = 1536 GB ?

Sorry for the trivial question, thank you.

Re: What is the maximum memory supported by T4240 and T2080

Bulat — Tue, 11 Jan 2022 04:43:23 GMT

Gb means Gbit, i.e. 8Gb = 1GByte. So calculations are correct.