Partytap

The Partytap is used in the following games:

• Casino Derby
• Gimmi a Break - Shijou Saikyou no Quiz OuKetteisen
• Gimmi a Break - Shijou Saikyou no Quiz OuKetteisen 2
• Project Q

It consists of 6 separate 1-button controllers (labelled buttons 1 to 6 below)

Hardware interface

Input ($4016 write)

7  bit  0
---- ----
xxxx xxxS
        |
        +- Controller shift register strobe

Output ($4017 read)

7  bit  0
---- ----
xxxC BAxx
   | ||
   | |+- Serial data (Button 1, Button 4)
   | +-- Serial data (Button 2, Button 5)
   +---- Serial data (Button 3, Button 6)

The first read returns the state of buttons 1 to 3, the 2nd read gives buttons 4 to 6. The third read apparently returns a detection value ($14).

The device supposedly requires a relatively large number of cycles between writes/reads (games wait up to 80-500 cycles in-between some operations).

References

• nocash's NES documentation: http://problemkaputt.de/everynes.htm#controllerspushbuttons
• https://forums.nesdev.org/viewtopic.php?t=903