Can I tie the VPP/VCC pin of an XC1700 PROM through a resistor to +5V?
(This may be desirable is a user is switching between Xilinx and Atmel PROMs.)
Do not use a resistor between VCC and VPP pins on XC1700 devices. This has severe impacts on speed and data reliability, as VPP is actually the power supply for the read section.
If you are using a resistor between the VCC and the VPP, be aware that this will affect the reliability and speed of the part.
To prevent this problem, tie VPP and VCC directly to +5V.