I'm a newbie of making nes/fc reproduction cartridges. According to the nesdev wiki, I made a few mappers of the carts, like cnrom, mmc1, mmc3, vrc1... and many thanks those who provide so much detail information.
I used some cheaper flash chip and eeprom: en29f040, mx29f040 and W27C020. They are cheaper than AMD chips and work fine on the above mapper carts.
When I making namcot 163 and vrc4 carts, the problems came. both are blank screen when I replace the flash chip. the cheaper chips seems unfit the namcot 163 board well. So I designed a tsop2dip board to carry a tsop amd chip, like am29f080b (tsop nor flash chip is still cheaper than dip). am29f080b works better, #oe binded to #ce, the game can be played but the graphic is not right. I tried to bind #oe to GND, graphic is worst but the game still can be played. I also put 74hc00 in the circut to deal with the chr chip ce, but the graphic still not correct.
for vrc4 board, even using am29f080b burned with the original game to test, the screen is still blank... I put the original mask roms back and the cart run correctly. It means the board is ok.
Must I use a am29f040b to finish the reproduction? or what did I lost something?
I used some cheaper flash chip and eeprom: en29f040, mx29f040 and W27C020. They are cheaper than AMD chips and work fine on the above mapper carts.
When I making namcot 163 and vrc4 carts, the problems came. both are blank screen when I replace the flash chip. the cheaper chips seems unfit the namcot 163 board well. So I designed a tsop2dip board to carry a tsop amd chip, like am29f080b (tsop nor flash chip is still cheaper than dip). am29f080b works better, #oe binded to #ce, the game can be played but the graphic is not right. I tried to bind #oe to GND, graphic is worst but the game still can be played. I also put 74hc00 in the circut to deal with the chr chip ce, but the graphic still not correct.
for vrc4 board, even using am29f080b burned with the original game to test, the screen is still blank... I put the original mask roms back and the cart run correctly. It means the board is ok.
Must I use a am29f040b to finish the reproduction? or what did I lost something?