The CPU in the gamepad is an ARM926EJ-S.
The CP15 ID registers read the following values:
| Register | Value | Desc. |
|---|---|---|
| c0,c0,0 | 0x41069265 | CPU ID register |
| c0,c0,1 | 0x1D152152 | Cache info register |
| c0,c0,2 | 0x00000000 | TCM info register |
The caches are 16K each, with 32-byte lines and 4-way associativity. There are no TCMs.
The UIC is the gamepad's auxiliary microcontroller, handling input, power management, and storing settings in its EEPROM.
It is a STM8 microcontroller. The pinout of the UIC chip matches a few STM8 models, so the UIC is likely just one of these with custom marking.