The mezzanine board includes a LCD-graphic 128x32 pixels display panel (with blue background white pixels and white backlight) that is configured from control DSP-2 via an SPI bus.
It also includes a button navigator with five switches (four arrow buttons: Up, down, left, right and center OK button) used to navigate through the LCD menus.
Additionally, there are five 3-mm red LEDs and five 9-mm potentiometers. A 5K potentiometer (VR5) in the middle, controls the distortion octaver level. The other four 50K potentiometers (VR1-4X) are connected to analog SAR ADC inputs (AIN0-3) on DSP-1. Only two of them (VR3-4) are connected to DSP-2 (AIN2-3) since AIN0-1 are connected to tuner and noise suppression circuits respectively.
These may be used as digital potentiometers to configure some effect parameters such as gain, volume, tone, depth, delay, rate... on LCD menu.