### X9C104 Annotation Also Trademarked as XDCP - Xicor Digitally Controlled Potentiometer **Datasheet:** [[X9C104.pdf]] #### Pinout ![[Pasted image 20250305052636.png]] !CS, !INC, and U/!D are the three input pins. - Chip Select - Increment - Up/Down R_H, R_L, and R_H are the three output pins. - Resistor High - Resistor Low - Resistor Wiper #### Block Diagram ![[Pasted image 20250305052837.png]] Power the chip, and use the three inputs to store a wiper position as a 7-bit number in non-volatile memory using the counter circuit. Then the counter value passes to a 1-100 decoder and selects the wiper position accordingly. - Enable the chip by pulling `!CS` **LOW**. - `!INC` is negative-edge triggered. - Hold `U/!D` to control wiper movement and increment to where you want to be. - The current counter value is stored in memory when `!CS` rises to **HIGH** while `!INC` is also **HIGH**. - The device remains in low-power standby mode until selected #### Electrical Specs - Total resistance variation is ±20%. Which is a bit more than I expected. - The chip is probably cheap. - ±4.4mA max current through the wiper. - Wiper resistance itself is 40-100Ω. - Active Current (during counter operation): 1-3mA - Standby Current (!CS = **HIGH**): 200-750uA - ±10uA of leakage current possible (!) - At all times, voltages on the potentiometer pins must be less than ±Vcc. ![[Pasted image 20250305053829.png]] #### Mode Selection - Input Controls ![[Pasted image 20250305055632.png]] The system may select the pot, move the wiper, and then de-select the device without storing the last wiper position into memory. the `!INC` pin determines whether it gets saved or not, when `!CS` rises. It may be convenient to save a calibrated default value, and then dynamically adjust without overwriting. #### Basic Circuits ![[Pasted image 20250305055939.png]]