PS2 optical mouse - brand unknown.
The 12-pins IC (integrated to the camera) is an ATL A2188 for which I found no datasheet in the Web.
Checked the rotary encoder used for the scroll wheel: mechanical switches with detents.
After probing its terminals with a scope, I realized that each switch brings in turn, in ON / OFF sequence its respective pin to ground.
Also the 3 microswitches (left - right - wheel) do exactly the same, bringing their respective pins to 0V when pressed down.
My question: the pull up "resistors" inside the IC, what are they? Common resistors or active transistors?
Additional (not related to the above): in the waiting state, the LED is driven permanently with a 6% duty cycle. For full brightness DC becomes 100%. Frequency is 96 Hz.
The sole resistor used in this mouse goes in series between the +5V and the LED.
The 12-pins IC (integrated to the camera) is an ATL A2188 for which I found no datasheet in the Web.
Checked the rotary encoder used for the scroll wheel: mechanical switches with detents.
After probing its terminals with a scope, I realized that each switch brings in turn, in ON / OFF sequence its respective pin to ground.
Also the 3 microswitches (left - right - wheel) do exactly the same, bringing their respective pins to 0V when pressed down.
My question: the pull up "resistors" inside the IC, what are they? Common resistors or active transistors?
Additional (not related to the above): in the waiting state, the LED is driven permanently with a 6% duty cycle. For full brightness DC becomes 100%. Frequency is 96 Hz.
The sole resistor used in this mouse goes in series between the +5V and the LED.
