EP9312 & SDRAM

Nov 28, 2003 1 Replies
S

Hi,



Does anybody have any experience designing with the Cirrus EP9312 processor? I'm looking at using it for a project but it's unclear to me how to physically connect SDRAM modules to the processor's address bus.



The SDRAM chapter of the EP9312 user's guide [1] shows how the processor maps address bus signals to the signals for the SDRAM address and bank selects (SYA[13-0], SYB[1-0]). Unfortuneately the device data sheet [2] makes no mention of the SYA and SYB signals, only the general address bus pins AD[25-0]. I'd like to know which pins #'s on the processor are actually used to address SDRAM. I found an app note for the EP7312 [3] that tells me exactly what I need to know but I haven't found a similar document for the EP9312. Can anyone help?



TIA,



Scott


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S

Unless it sprouted another 12 or so DRAM address lines since 2001 when I last worked with it the address lines of the SMI (static memory interface) are shared with the SDRAM controller - that is,the DRAM and SRAM-like-peripherals share a common address and data bus.Obviously things like nCAS and nRAS aren't shared.

Thus,the DRAM parts should be physically closest to the 9312 and if you have a lot of SRAM-like-peripherals you should take note of the bus capacitance and add a 74LVC16245 as appropriate.

The 7312 is completely unrelated to the 9312.If you're still stuck,drop your FAE a line and ask (not as quick though!), Sprow.

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