Water meters require several functions to measure water use, including the capability to calculate water usage amount, an LCD display on which to present the data, and a data communication function with external devices. These functions must reliably operate with limited battery capacity for a specified period of time.

To support the design of water meters, Renesas offers a lineup of the RL78/L1x microcontrollers (MCUs) that support three LCD driving voltage generation methods (internal boost, capacitance division and external resistance division). Renesas also offers the RL78/H1D MCU equipped with UART that can communicate up to 19200bps with a subsystem clock (38.4kHz), sampling output timer and detector function suitable for rotation detection by magnetoresistive (MR) sensor; it is suitable for impeller water meter construction.