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).
7 bit 0
---- ----
xxxx xxxS
|
+- Controller shift register strobe
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).
- nocash’s NES documentation
- Forums - Party Tap (in Japanese)