tepples wrote:
kevtris wrote:
You have to invert the reset line for it to function properly (the button is active high, the /RST line is active low). By far easier to simply cut pin 4.
Unless you're modding NES systems for region free and keeping the CICs to solder onto repros. Then wouldn't you be able to replace the CIC with a hex inverter and a bit of wire?
In which case, it's easier to just buy CIClones for your repros, hehehehe. Cutting pin 4 makes the NES region free. It will even run air (i.e. no cart).
A long time ago, I did this by using a transistor. Takes an NPN transistor, and some resistors, and a larger cap than what is on the board. The cap performs the essential power-on reset function.
Maxim and others make purpose-built chips that are 8 pins which perform power-on reset functionality with a reset button input. They are pretty nice. You get low-voltage lockout (so you don't have to hold reset when turning power off for your zelda cart), 250ms or so reset on power up (to make sure everything's stabilized) and some have a reset button input.
the MAX705 stuff is what I'm thinking of. There's about 20 or so parts in the family.