Interest check! New high quality Famicom mini PCBs with sockets for ppu and cpu

[CloudGamerX]

Oh dang, guess some of the wiring still needs to be worked on. Well I hope to see more as time goes on!

[aarkay14]

Oh dang, guess some of the wiring still needs to be worked on. Well I hope to see more as time goes on!

Yes! I really dont know why it is happening, the symptoms are a grey screen. I think the CPU and RAM and not interfacing correctly. I used new type of SRAM ... I dont know if that is the cause. Need to check.. need time.

-Rama

[CloudGamerX]

A gray screen would suggest inactivity between the CPU and RAM. Perhaps check if one of your parts is faulty, and check the tracing for any incorrect routing.

[aarkay14]

Hi All,

After some investigation, I think I found the fault with my design. If someone can help me confirm this then it will be a real help!

I am using the 6116LA25SOG8 IC in my design. Its pinouts are like this:



And the NES Wiki shows that 6116 type SRAM can be used, the pinout being like the below:

Code Select Expand

   
    +-----+--+-----+
 A7 |1    +--+  24| VCC
 A6 |2          23| A8
 A5 |3          22| A9
 A4 |4          21| /WE
 A3 |5          20| /OE
 A2 |6          19| A10
 A1 |7          18| /CE
 A0 |8          17| D7
 D0 |9          16| D6
 D1 |10          15| D5
 D2 |11          14| D4
GND |12          13| D3
    +--------------+


May I ask you to kindly confirm if this is really compatible chip?

-Rama

[CloudGamerX]

It seems to be pin compatible, but you're still having issues. Check to see if the RAM itself is faulty, or if a signal is left floating on your PCB.

[P]

If you have an arduino (or other microcontroller and programmer with some kind of UART monitor) it would be easy to test. Just hook it up and write all bytes, read them and output to the serial monitor. Then do it again with another fill value to make sure the whole RAM is ok.