Water meters need the capability to calculate water usage amount, an LCD display, and data communication function with external devices. Also, these functions must stably operate with limited battery capacity for the period specified.

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

Water Meter

System Block Diagram

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