lidnariq wrote:
game-tech.us actually explains why it's working on the "how to use" page...
E and J control whether pin 1 on a 32-pin ROM is pulled high, low, or ... if unpopulated, left to float.
Not all ROMs care about what pin 1 is doing. The ST microelectronics M27C1001 datasheet I have says that pin 1 can be "VCC or VSS" during normal operation. I wouldn't be surprised if the physical hardware only distinguishes between "Vpp voltages" and "enough less"—and while leaving the pin to float probably draws extra power, it's evidently functional.
Game Tech asked me to post this question/feedback here specifically. Mind you this is one of my first experiences with repros. I'll be honest I'm not savvy enough with pinout and Hi/lo's. Perhaps I just need some education on it in laymen terms.
On the how to use page on his site it lists this for UN/OROM:....
E 32 pin – check datasheet, if pin 1 needs tied high: 2-3, if low: 1-2, if NC no jumpers
J 28pin chips no jumpers, 32 pins check datasheet usually pull high (1-2) if it needs pulled low jumper 2-3
....
Aside from E - If I'm reading that right J with a 32 pin chip needs a jumper regardless of hi/lo on un/orom. Could be possible I'm misunderstanding, hence the post.