San Jose, Ca. - As if to prove there is still life yet in the 8- and 16-bit microcontroller market, Renesas Technology America,Inc. has just introduced a new generation of R8C/Tiny series microcontrollers (MCUs) that are based on the latest process technology tailored for low-end devices.
Built on a 16-bit CPU core, the R8C/3x MCUs with on-chip flash have an extended
operating voltage range of 1.8V to 5.5V and incorporate new and enhanced analog functions, including level-only-sensitive power-on reset circuits, digital-to-analog converters and analog comparators.
In addition, their overall performance has been boosted by the addition of a data transfer controller (DTC) and a background operation (BGO) function for flash memory rewriting.
The new devices are in three product groups: the 52-pin package MCUs in the R8C/35A group, the 32-pin package chips in the R8C/33A group, and the 20-pin package devices in the R8C/32A group. All of the new MCUs maintain compatibility with existing R8C/Tiny products and are targeted at home appliances, sensor networks, power management equipment and building automation products.
According to Ritesh Tyagi, director of Renesas' system LSI business unit, the data transfer controller (DTC) has been added as a coprocessor for efficient data movement and a background operation (BGO) function for flash rewrite operations without CPU intervention. Specialized hardware blocks manage complex
operations automatically, freeing up the CPU to execute extra functions and thereby enabling end systems that are more feature-rich and robust."
"This form of 'co-processing' capability is typically found only in high-end MCUs that are too expensive for cost-sensitive applications," he said. "The DTC performs functions similar to those of a direct memory access controller."
The DTC unit manages data transfers from memory to memory, or memory to peripherals, without CPU intervention. While the DTC is handling the data transfers automatically, he said, the CPU can perform other operations, so overall system performance can increase.
"Moreover, the DTC is tightly coupled to the peripherals so that any hardware interrupt event can trigger the DTC to move data from one location to another in
memory automatically for fast response," said Tyagi.
This capability is useful in many situations such as, for example, in performing frequent operations such as transfer of consecutive analog-to-digital (A/D) conversion results to RAM. When the DTC is used to move data from the A/D to RAM, it eliminates interrupt processing through the CPU, reducing this
operation's execution time significantly.
The data flash in the new R8C/3x MCUs has a BGO function that allows the CPU to execute instructions while data is being written to or erased from the data flash.
"This makes program development much easier because no special consideration needs to be given to the timing of data flash write and erase operations," said Tyagi.
Among the new functions available in all devices are multiple analog comparator circuits, a power-on reset controller that supports slow-rising power supplies, and an A/D unit with multiple conversion-result registers.
The members of the 32-pin R8C/33A group and 52-pin R8C/35A group also include a digital-to-analog converter (DAC). The analog features of R8C/Tiny MCUs make the devices good choices for sensor applications.