I read this from the primer (Mystery Pins):
http://wilsonminesco.com/6502primer/MysteryPins.htmlQuote:
BE: The bus-enable input allows external control of the buses. If you don't want to further investigate this possibility through other sources, then pull this up to +5V through a 3.3K resistor. You'll only find this pin on WDC's 65c02's anyway, not on those of other manufacturers.
So....If I want my board to work with any 65C02, and I only care about 65C02 in general (no NMOS), then should I bother putting a jumper for the BE pin to a 3.3k pull-up?
I only have WDC 65C02. Or, should I just go ahead and tie that pin to the 3.3k pull-up anyway?
Also, I *DO* want to eventually use this pin with some micro-controllers. If that makes a difference...
EDIT:
Also, I have the same question about the RDY pin. According to the primer and the datasheet:
Quote:
RDY: The "ready" input is used for single-stepping, wait states for slow memory, and DMA. Some makes of 65c02 have had internal weak pull-ups on RDY and other inputs, so you could get away without connecting it to anything. WDC has apparently removed this. Better not let it float. Note that WDC's RDY is bidirectional, and it will be pulled low if it gets the WAI (wait-for-interrupt) instruction in your program. (WAI puts the processor in a better position to make a fast-as-possible response to an imminent interrupt.) On the other hand, although you may not have any plans to use WAI, a crash could make the processor misinterpret a $CB operand or data byte as the WAI op code and possibly damage the chip through heating problems if the output is shorted to +5V. If you don't want to further investigate or use the features this pin is made for, and you want the circuit to be able to handle any manufacturer's 6502 or 65c02, pull it up to +5V through a 3.3K pull-up resistor.
It seems that you may not always want to put the RDY pin directly to a 3.3k pull-up as some users may want to drive it directly.
So, would you recommend I put a jumper from the RDY pin and 3.3k pull-up as well?
BTW, this is for a proto-type board for the 65C02 and not a SBC, per se.
Thanks.