Merlin lens control

Merlin is equipped with two liquid lenses which are electronically controled.

Two liquid lense controllers MAX14515 provide focus adjustment in 255 steps. Both lens drivers are attached to I2C Bus I2C1 of the Raspberry Pi CM4 on address 0x76.

• CM4_GPIO2, ALT0 → SDA

• CM4_GPIO3, ALT0 → SCL

See https://datasheets.raspberrypi.com/cm4/cm4-datasheet.pdf section 2.5.1 on page 9 for details on the mapping of I/O pins.

GPIO_25 of CM4 is attached to EN of both lens drivers.

GPIO_26 of CM4 is used to select which lens driver is attached to the i2c bus:

• GPIO_26 = 0 → Lens driver 0 (right eye) → Lens on J350

• GPIO_26 = 1 → Lens driver 1 (lieft eye) → Lens on J352