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.
|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|