Hello!
I've soldered together the hardware for a copynes...more or less.(I don't have the || port attached yet, but that's not important.)
Right now the code burned (flashed) simply disables the add-on circuit and JMPs (FFFC).
The problem: The cart will only start up on a full system power-on, and then only about 1/5 of the time. If I use the reset button on the NES, it NEVER works. (Blank blue screen.)
I'm using all 74LS parts for the four small ICs and a MOS 6522 (ripped from an old CMB floppy drive).
My ROM is a Winbond (W29EE011-15) Flash ROM. (I have some eproms, but no eprom eraser.)
I have bypass caps everywhere, tested the circuit for shorts, double checked every pin and every connection, and everything looks good.
I've tested the port bits on the 6522 and the select line on the 157 and everything is as it should be, but no go on the cart.
Any help appreciated..
I've soldered together the hardware for a copynes...more or less.(I don't have the || port attached yet, but that's not important.)
Right now the code burned (flashed) simply disables the add-on circuit and JMPs (FFFC).
The problem: The cart will only start up on a full system power-on, and then only about 1/5 of the time. If I use the reset button on the NES, it NEVER works. (Blank blue screen.)
I'm using all 74LS parts for the four small ICs and a MOS 6522 (ripped from an old CMB floppy drive).
My ROM is a Winbond (W29EE011-15) Flash ROM. (I have some eproms, but no eprom eraser.)
I have bypass caps everywhere, tested the circuit for shorts, double checked every pin and every connection, and everything looks good.
I've tested the port bits on the 6522 and the select line on the 157 and everything is as it should be, but no go on the cart.
Any help appreciated..