Can I drive old 5 volt TTL input logic with the 3.3 volt outputs of the XC9572XL?
What is the size of your board? Will it fit onto a generic plastic breadboard?
If I use your board on a generic plastic breadboard what maximum clock rate do you recommend?
Yes, it should work with TTL:
A TTL input signal is defined as "low" when between 0 V and 0.8 V with respect to the ground terminal, and "high" when between 2.2 V and 5 V
http://en.wikipedia.org/wiki/Transistor ... stor_logic (http://en.wikipedia.org/wiki/Transistor%E2%80%93transistor_logic)
Yes, it will fit in a plastic breadboard. The max clock rate depends on your applications I guess. Board is approx 50mm by 30mm.
Also, the XC9572XL is 5V-tolerant on the inputs (look at the data sheet: http://www.xilinx.com/support/documenta ... /ds057.pdf (http://www.xilinx.com/support/documentation/data_sheets/ds057.pdf) ). The maximum clock rate is 100MHz (since it is a XC9572XL-10), but if you have more than simple logic (e.g. you add counters, or D-flip-flops) this will go down.
Thanks for all the useful info, Guys!
Looks like I am limited to <= 10 MHz clock if I use a generic plastic breadboard:
Areas where the common breadboard does poorly:
High voltage
High frequency (above 10MHz)
Where the additional breadboard capacitance would present problems (oscillators, etc)
Where glitches due to poor wire connections would result in poor operation
Where most of the parts are not through hole 0.1" (2.54mm) centers
For anything but on-the-bench prototyping (ie, don't take it out of the lab and expect it to work)
Sensitive analog electronics, such as sensor usage