Hi! email@example.com írta: > > Correct me if I"m wrong, but the ISA bus's only NMI line, per se, is the > parity error line. Since the c64 wont be generating parity (anyone got a > parity gen circuit?), I feel it's best to leave it unhooked so the poor > thing doesnt get an NMI on every bus access. ;) The ISA NMI line is rather like a special IRQ line than a parity check signal from the mainboard. Some cards actually depend on that possibility. The Gravis Ultrasound uses NMI for Sound Blaster emulation; sbos refuses to run if the mainboard supports no ISA NMI (or if you disable NMI, ie. parity check on older mainboards in the setup). These cards should indeed represent a minority - just wanted to point out that NMI can be used for other purposes than parity check too (depends on what you hook the NMI vector for). Best regards, L. Ps. I found a dual 16550 serial port ISA card in a garage shop yesterday. It is built from standard chips + 2 real DIL 40 pin 16550s in sockets, so if anyone is planning some 16550 hacks with his C64 and can't find the chips (or they're expensive), just let me know and I'll send some. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail firstname.lastname@example.org.
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