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RE: SDRAM



Hi steve.
The SDRAM clock enable signal should be connected to ETRAX pin D5. A10/precharge is connected
to Etrax A11 (pin C11) in 16 bit mode and ETRAX A12 (pin B11) in 32 bit mode.
I'll think you'll find the examples on
http://developer.axis.com/doc/hardware/etrax100lx/SDRAM_design.html
helpful. 
It's hard to say weather resistors on the address bus is needed or not, I guess it depends
on how the PCB layout is made (trace length etc.). On the boards that we have made there are no
resistors for the address bus. These boards normally have 4-6 layers ( 1 GND layer and 1 Power layer)
and the trace length for the address lines normally stay within 10 cm.

/Magnus 

-----Original Message-----
From: Steve Jones [mailto:sjones@xxxxxxx.uk]
Sent: den 2 december 2002 17:30
To: Magnus Mårtensson; :dev-etrax@xxxxxxx.com
Subject: Re: SDRAM


What do you connect clock enable on the sdrams to. Also Does A10/precharge
on the SDRAM go to A10. I am used to coldfire which has signals
A10_precharge, A10 and SDRAM_Clock_Enable.
Also why arn't 22R added to address bus as well.

Thanks again


Steve
----- Original Message -----
From: "Magnus Mårtensson" <magnus.martensson@xxxxxxx.com>
To: "'Steve Jones'" <sjones@xxxxxxx.com>
Sent: Friday, November 29, 2002 9:00 AM
Subject: RE: SDRAM


> Hi Steve.
>
> We have made a design that has a 8 MB module externally so that the SDRAM
bus accesses are 32 bit wide.
> We use 22R on the data bus and the SDRAM clock and it works fine.
>
> Regards
> /Magnus
>
> -----Original Message-----
> From: Steve Jones [mailto:sjones@xxxxxxx.uk]
> Sent: den 28 november 2002 18:29
> To: dev-etrax@xxxxxxx.com
> Subject: SDRAM
>
>
> When adding external SDRAM to the MCM chip do any of the signals require
inline resistors, if so which ones and what values are required/recommended.
>