Renesas Electronics RL78 Microcontroller

Product Summary

The RL78 microcontroller is a compact 8-16 bit microcontroller that uses Renesas' unique core architecture. It boasts a wide lineup of package types and ROM capacities while achieving the industry's lowest level of power consumption. In addition, it is equipped with a high-precision (±1%) high-speed on-chip oscillator, background operation data flash that can be rewritten 1 million times, a temperature sensor, multiple power supply interface ports, etc., which contributes to reducing customer system costs and downsizing of systems.

Since its launch in 2011, this product has been adopted by many customers, with a cumulative shipment of approximately 9 billion units.

Features

Ultra low power consumption

The principle for reducing the power consumption of an MCU is to "use only the necessary functions when necessary."

Based on this principle, the RL78 has three low power consumption modes to achieve low power consumption.

1. HALT mode
The operating clock of the CPU is stopped. A clock is input to peripheral functions, allowing them to quickly return from an interrupt request. If no processing is required, the CPU is stopped, thereby achieving low power consumption.

2. STOP mode
This mode stops the clocks for the CPU and peripheral functions, further reducing power consumption than in HALT mode. It can be released from an interrupt request, but because there is a wait time for the clock to stabilize, the delay until interrupt processing starts is longer than in HALT mode.

3. SNOOZE mode
A transition from STOP mode is made for specific peripheral functions, such as AD conversion and UART reception. In the case of AD conversion, the CPU is not woken up unnecessarily because a threshold is compared to determine whether to wake it up. In the case of UART reception, data is immediately received from the clock stopped state by a receive interrupt. If the received data contains an error, the CPU is not woken up and the device returns to STOP mode.

For example, the RL78/G22 and RL78/G23 have an expanded range of peripheral functions that can use this SNOOZE mode, and it is now possible to start the DTC and capacitive touch functions without waking up the CPU, making these MCUs with even more refined low power consumption features.

Scalability

There are 37 series of devices in the RL78 family, and when you take into account the lineup of packages and memory capacities, there are more than 1,500 types to choose from. There are three approaches to scalability:

We have tried to keep the layout of peripheral function pins and I/O pins between series to a minimum, reducing the design burden of layout patterns when migrating between RL78 series.
We have a wide lineup of built-in flash memory sizes, from 1 to 768 KB. This allows us to flexibly respond to the needs of our customers' applications. Some devices also allow you to choose between a version with data flash or a version without data flash.
A lineup ranging from 8 to 144 pins and package types are available to meet a wide range of customer needs.