- #1
bigzuo
- 1
- 0
if i want to connect a comparator chip's output (TTL) to Spartan2 FPGA board, can i directly do it, do i need to consider the impedance match? when i directly connect them, I will see the transition on the edge of the waveform stored (after FPGA processing, i save the output of FPGA and plot on matlab) but when i terminate some resistors between them, these transition will become less( up to resistor's value), then let's say i found 1 kohm will sort out this problem, but only sometimes, not always, the other time the transition will appear again! i have no idea about this problem, could someone give me a clue. Thanks a lot!