[En-Nut-Discussion] Mapped memory extension

[Martin Kresse]

Hi,

I am pretty much a newbie, not only regarding ethernut but also hardware 
design in general. Nonetheless I'd like to expand the memory on my 
Ethernut (revision 1.3 f), so I can do some buffering for playing 
internet radio. With my limited knowledge, I designed the attached 
scheme, and I'd be glad, if some experienced person could have a look at 
it and tell me if this is going to work like I hope it should.
The scheme does pretty much what was already suggested by people in this 
forum: a 16kByte address window controlled by a bank select register. I 
tried to make it simple, and since I don't know how to move the RTL 
controller from its base address 0x8300 away, I chose the following 
memory layout (opposing to what the guide "Memory Considerations" 
recommends):

0x0000 - 0x7FFF:    internal memory etc.
0x8000 - 0xB7FF:    memory mapped I/O (e.g. Ethernet controller), 
segmented in 8 x 2kb regions
0xB800 - 0xBFFF:   bank select register
0xC000 - 0xFFFF:   bank switched memory window

Are there any 512k RAM chips in standard DIL package (easier to solder) ?
I'd appreciate any comments - thanks in advance.

Sincerely,
 Martin Kresse
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