John,

I called Russel Anderson of TI and asked if "contention" would result from access to internal SRAM in the case where external RAM was mapped and selected in the same address space.

Since the DATA portion of the bus cycle is not effective (i.e. does not emit from the micro during this access), no electrical contention exists.

Although your external decode could selected and enable the external RAM, access would occur to the internal RAM with the contents of the external RAM being ignored.

regards,
p