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RE: Memoryconfiguration



Hello mr Chanda,

>Now I have a boot block of a total 128 KByte (in every chip 64K). Is
>this correct? 

Yes, that is correct. In the kernel configuration you have to modify
two values. 

CONFIG_ETRAX_FLASH_BUSWIDTH should be set to 4
Set bit 0 of R_BUS_CONFIG to 1 to indicate 32 bit flash

You also have to pull-up BS0 on the PCB to select 32 bit.

The partition table for the software should also be updated.
The rescue partition (if used) must end on a block boundary.

>How many chips can a ETRAX 100LX drive?

The maximum output current for most pins is 4 mA. The maximum
load is 50 pF (not 100 % sure about this). Not all chips 
connected to the address bus are enabled simultaneously.
The DIMM modules are divided in two groups and we only use 
32 of the 64 bits at any time. Depending on the internal
organization of the module this means that either 2 or 4
chips are enabled simultaneously. 

We recommend a clock buffer on the SDRAM clock signal when
connecting a DIMM module (the clock signal is connected to
8 inputs).

Refer to the designer's reference electrical information
chapter for more information.

http://developer.axis.com/doc/hardware/etrax100lx/des_ref/ET100LX_20_Electrical_Information_010712.pdf

Regards
/Mikael
-----Original Message-----
From: owner-dev-etrax@xxxxxxx.com]On">mailto:owner-dev-etrax@xxxxxxx.com]On
Behalf Of Pijus Chanda
Sent: Wednesday, October 17, 2001 6:24 PM
To: dev-etrax
Subject: Memoryconfiguration


Hi
As a newbie to the ETRAX 100LX world, I have two questions concerning
memory configuration:
 
I want to connect 2 flash (each 8 MByte) to a Etrax 100LX, one connected
to the lower 16 bits, one connected to the upper 16 bits. All other
connection are in common. This kind of flash have 22 Addresslines, that
would be connected from A2 to A23.
Now I have a boot block of a total 128 KByte (in every chip 64K). Is
this correct? And if yes, I suppose, I do have to change the kernel
configuration?
 
You have given a sample configuration with a standard PC100/133 DIMM
connected to the Etrax 100LX. What about buffers for at least the
address lines? To my knowledge, a standard 8-chips DIMM has 8 chips
connected to the address line. Additional loads to address lines would
be also from 2 flash chips. How many chips can a ETRAX 100LX drive?
 
Thanks a lot.
Pijus Chanda