Hi Rob,
Thank you for the pointer.
The 89V51RD2 is both TTL and CMOS compatible.
Hi-Level input voltage is 0.2 Vdd + 0.9 , which works out to 1.9V for a Vdd of 5V.
The data sheet for the flash says that output high voltage can be -0.6 to VCC+0.6. So as long as it is above 1.9 V I would not need a level translator. Since the port on the micro is made high when using it as an input port, I think I will not need a level translator in this case.
Is this a reliable setup ?

Regards
Thomas