Hi Erik,

Thanks for your time -

> Only the first 8k of flash is accessible for write.
We are using a 64k flash but but only actually using 16K of it.
8K for code and 8K for a non-volatile 'database'.

> Are you modifying something that works ?
No, it's a schematic...

> What instruments do you have available (ICE, scope, logic analyzer)?
I'm looking into buying an ICE as I think it's going to be impossible to get by without it.
I have my bootcode running on an evauluation board (ie all Internal Flash/Ram) and am now worrying that
the external devices will not be configured to allow me access to everything I need.


I'll try to explain it a bit better..:


FLASH connections: (a 64K device but I only use 16K as two 8K blocks - one CODE, one NV Database)
A0-A13/D0-D7
16K address access.

/PSEN, /RD connected to /OE of FLASH
This allows instruction fetching and 'const code' data read.

/WR connected to /WE of FLASH
This allows (using the correct address) data write access.

Y2 from decoder connected to /CE of FLASH
This bit is set by writing to an address with A15 - hence writes to H8000+ will write into FLASH.


RAM connections:
A0-A12/D0-D7
8K address XDATA access.

/W connected to /WE, /RD connected to /OE
Standard connections.

Y0 from decoder connected to /CS of RAM
This bit is set by writing/reading to any address where A15+A14=0 - so addressed H0000-H1FFF.


FLASH and RAM access are my two worries.

Kev