In the board that has been shipped, the LCD contrast is set by the resistir divider, R69 and R68. This can be seen in the board schematic . To set the contrast manually,
- R69 and R68 has to be removed
- R67 has to be soldered. R67 should be a potentiometer of value 10k.
- Adjusting R67, sets the contrast.
If you are using CY8CKIT-001 Developement kit, then the potentiometer R31 is used for LCD Contrast Adjust.