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.

Water Meter

Block Semiconductor Ddevice Recommended Products Features
Main Controller MCU RL78/L1x 24MHz, 16-bit, true low power, on-chip LCD controller/driver
RL78/H1D 24MHz, 16-bit, true low power, on-chip LCD controller/driver, on-chip timer for MR sensor
RL78/I1D 24MHz, 16-bit, true low power, 12-bit A/D converter
Communication Sub-GHz RF Transceiver RAA604S00 RF frequency range: 863MHz to 928MHz, IEEE802.15.4g / 4e compliant hardware function
MCU built-in Sub-GHz RF Transceiver RL78/G1H 32MHz, 16-bit CPU, RF frequency range: 864MHz to 928MHz
MCU RL78/G14 32MHz, 16-bit CPU, true low power, European home appliance safety standard(IEC/UL 60730)support