CN-ROM 128kb CHR memory?

[Ben Boldt]

You should have places for diodes with the battery. Refer to the section “Battery backup” here:

https://www.nesdev.org/wiki/PRG_RAM_circuit

Code: Select all

                    D1           ___________
    5V -------------|>|--+      |       RAM
                         |---+--| VCC
    3.3V battery----|>|--+   |  |
                    D2       R1 |
                             |  |
   RAM /CE decoding logic----+--| /CE
                                |___________

When there is no battery, you can put a jumper instead of D1. When there is a battery, you want both diodes. The RAM chip consumes a lot of power when the game is running, so it is important that the console provides the power with the diodes when running.