Trends in Microcontroller （1）

Published:2011/7/31 20:56:00 Author:Phyllis From:SeekIC

By Christian Tavernier

AN ABUNDANCE OF CHOICE

The number of different microcontrollers on offer just keeps on growing. Nearly every single week a new product appears on the market. Choosing the right microcontroller for a particular design is becoming increasingly more difficult. Reason enough to appraise the latest developments.

16-bit devices appear to be old hat

The microcontroller market is mostly dominated by a few ’heavyweights’ such as Microchip, Atmel and, to a lesser extend. Philips. In addition, there are many smaller manufacturers who make very interesting developments in this area. There are also a number of manufacturers who are not at all that well known for their microcontroller products, and are often forgotten as a consequence. Names that come to mind are Toshiba with its TMP86xxx- family, and Zilog, the inventor of the famous Z80, who now offers the Z8 Encorel and eZ80 families. Also don’t forget Dallas Semiconductor with its DS89C420, Cypress with its PsoC (Programmable System-on-Chip) such as the CY8C27x, or the, until recently, completely unknown company Cygnal with its C8051xxx.

The majority of these products, however interesting, will have to have some very desirable properties in order to secure a prominent spot in an already oversupplied market. A few years ago, the PIC from Microchip succeeded in doing this. For other manufacturers this is not a problem; Toshiba, for instance, makes enough end products such as notebooks and other consumer electronics to use plenty of its own microcontrollers.

In this article we will concentrate mostly on the products of the larger manufacturers, because their broad experience and significant head start means that we can expect the most innovative developments to come from them.

Larger or smaller?

A very obvious trend is that the microcontrollers are becoming increasingly more powerful: more memory, more inputs and outputs, more integrated peripherals, etc. A lesser-known development is currently in progress at the bottom end of the market, both at Microchip, and, to a smaller extend, at Atmel.

For example, Microchip developed the 12Fxxx from the 12Cxxx. The different letter indicates an important difference: the 12C is an OTP (One Time Programmable) device, while the 12F is provided with Flash memory, which can be electronically programmed and erased a few thousand times.

These chips are available in either 8- or 14-pin packages and are mainly intended for low cost applications where until a few years ago microcontrollers were avoided because of their size or cost. Faithful Elektor Electronics readers will know the 12C508 (Figure 1), the first member of this family. But let us first take a look at the 12F629, which, in its 8-pin package has the following to offer: 1 k Flash program memory, an EEPROM 128 bytes in size, 64 bytes of RAM, 6 l/O-lines, an 8-bit and a 16-bit programmable timer. If all of this is not enough, the 12F675 may be more appropriate. Incidentally, the numbering scheme escapes us. This one is identical to the 629, but in addition provides a 10-bit, 4-channel ADC. These ICs operate from an internal RC clock source up to 4 MHz or from an external crystal up to 20 MHz.





Atmel hasn’t been sitting idle in this area either, and has the ATtiny-family, which comprises nine different versions. Even though it can’t really be called new, the ATtiny2313 deserves some of our attention. It has a 2 k Flash memory, a UART (Universal Asynchronous Receiver/Transmitter) and up to 18 l/O-lines. The crystal frequency may be up to 20 MHz. The controller is housed in a 20 pin package.

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