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.
| 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 |