Atlantis wrote:
Is it specified somewhere in the manufacturer documentation?
Yes, but not in those words. Ioh and Iol in the "DC Characteristics" table is the information you want. They show how much current you can pull from an output while keeping its voltage above/below the given threshold. Look up the corresponding input currents on the chips you want to drive, and their voltage thresholds, and if the 6502's output can provide sufficient current without dropping below the required voltage, that part is OK.
Then you need to look at the input capacitance of the devices you're driving, and make sure the output current can charge them to the threshold voltages in sufficient time.
Or, if everything in your design is CMOS, you can ignore all of that, because for small low frequency designs, CMOS is a close enough approximation to infinite drive and zero load that it doesn't matter.