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Volume 56 (Apr 26, 2006)
NEC Electronics' Microcontrollers: Supporting the Evolution of Car Audio from Behind the Scenes (2/2)
< Part 2 >
The appeal of microcontrollers with flash memory for car audio control
NEC Electronics, using the know-how it has accumulated in the field of microcontrollers for car audio use since the days of DTS, has recently developed the V850ES/SG3 and V850ES/SJ3 32-bit microcontrollers with flash memory. We asked Masaru Hirayama and Takeshi Itome, both of whom were involved in the development of these microcontrollers, about the appeal of these new products.
- Please explain the develop concept behind these products.
In today's car audio market, it is no longer just about AM/FM digital tuners and CD or MD playback. Great advances are being made toward increased functionality, including compatibility with compressed audio formats such as MP3, WMA and AAC, connectivity with mobile audio players, graphical display of information and compatibility with in-car networks.
As a top manufacturer of microcontrollers for car audio control, NEC Electronics used the know-how it developed back in the days of DTS to quickly bring the 20 MHz, 32-bit V850ES/SG2 and V850ES/SJ2 microcontrollers to market, and these new products have enjoyed immense popularity among our customers. Most recently, in an aim to further increase performance, we developed the 32 MHz, 32-bit V850ES/SG3™ and V850ES/SJ3™ microcontrollers equipped with high-capacity flash memory (Figure 2).
- What are the features of the V850ES/SG3 and V850ES/SJ3 32-bit microcontrollers?
While the maximum memory capacity of the V850ES/SG2 and V850ES/SJ2 was 640 KB, the V850ES/SG3 and V850ES/SJ3 are equipped with a maximum of 1 MB of flash memory. This additional memory not only meets car audio needs for increased multifunctionality, but also brings with it the advantage of inherited software resources. This is because there is more than enough memory capacity available to add software for new functions to tried-and-true software. In addition, since all of these products are equipped with flash memory and software evaluation can be carried out until the time of board mounting, they contribute to shortening of the development period.
The V850ES/SG3 and V850ES/SJ3 also have many other features inherited from the V850ES/SG2 and V850ES/SJ2. In addition to being equipped with the basic necessities for car audio control, for example, a timer, serial interface and in-vehicle LAN (IEBus, CAN), they also come with functions for solving oscillation trouble, including an external voltage detection function to guard against instantaneous interruption of power and a clock monitor function that makes it possible to reset the clock in the event of damage to the clock. In addition, the V850ES/SG3 and V850ES/SJ3 have a power voltage of 3.3V, and by strengthening the pin's resistance to pressure and using an N-channel, open-drain output function, we were able to create a pin capable of direct 5V input and output even without an external voltage converter IC. And since the software development tools are the same as those for the V850ES/SG2 and V850ES/SJ2, no new development investment costs are incurred. Moreover, compatibility can be achieved by simply changing the device file.
- You encountered some hardships during development, didn't you?
Since many of our car audio manufacturer customers had already decided to adopt the V850ES/SG2 and V850ES/SJ2, we had a difficult time planning their successors—the V850ES/SG3 and V850ES/SJ3. We met numerous times with both the design and development tool departments to discuss which parts should remain as they were and which parts should be improved, and these discussions always became heated over the issue of whether or not improvements would be possible. This just goes to show how serious everyone was about even considering the development of a new product.
If execution of peripheral functions were to differ even slightly from that of the V850ES/SG2 and V850ES/SJ2, then customers would be unable to carry over their existing software resources. We therefore paid particular attention to differences in analog characteristics resulting from changing the process (a 0.15 µm process was adopted) in an attempt to lower costs. It was only after suffering many hardships that we were able to assure our customers that they could use the same software for the V850ES/SG3 and V850ES/SJ3 that they had for the V850ES/SG2 and V850ES/SJ2 because the peripheral functions of the V850ES/SG3 and V850ES/SJ3 are identical to those of their predecessors.
- What are your future goals?
NEC Electronics' microcontrollers are currently being used by numerous car audio manufacturers around the globe. I believe that in the future, as information systems such as car audio and navigation systems become integrated with dashboard and other control systems, system needs (e.g., improvement of design efficiency, software standardization, high-speed in-vehicle LAN interface compatibility), will become increasingly diverse and advanced. We will continue to develop microcontrollers with higher performance and larger-capacity flash memory to pass on the know-how and achievements we have cultivated thus far.
- Thank you for taking the time to speak with us today.
NEC Electronics will continue to offer products that meet the growing needs for diversification and higher performance in car audio products.
• The V850ES/SG3 and V850ES/SJ3 use SuperFlash® technology licensed from Silicon Storage Technology, Inc.
• SuperFlash® is a registered trademark of Silicon Storage Technology, Inc. in several countries, including the United States and Japan.
• IEBus is a trademark of NEC Electronics.
