One 25-cent microcontroller replaces 25 different chips

By Richard Quinnell, editor-in-chief

Many designs contain a host of small, fixed-function devices to handle routine operations such as IO expansion, interface bridging, and keyboard sensing. But sometimes a designer would prefer a slight variation from the stock device, and maintaining an inventory of these many different parts adds to cost. A low-cost microcontroller that can replace many different such devices can address both concerns.

Texas Instruments has just introduced its lowest-cost member of the MSP430 microcontroller series with the aim of replacing a range of simple, fixed-function devices with one programmable part. The MSP430 family is designed to support low-power sensing applications and has a variety of analog and digital interface elements integrated on-chip, giving the MCUs tremendous application flexibility. The newest family members can cost as little as 25 cents in high volume and can serve as replacements for a wide range of common fixed-function ICs, with the added benefit of enhanced intelligence. Replaceable functions include such things as timers, communications, system housekeeping, and PWM controllers. Because the MSP430 family is available with non-volatile ferroelectric RAM, the value-line devices can even replace many types of EPROM.

To demonstrate the potential of its value-line MSP430 devices, TI has released an e-book  that provides application notes for different fixed-function devices that the MCUs can replace. These functions include IO expanders, serial interface bridges, motor controllers, system watchdogs, real-time clocks, serial EPROMs, and the like. The notes describe a total of 25 different device types replaceable with a single inventory part and include access to compiled code implementing the example.

TI supports its MSP430 series with its Launchpad line of development boards, which users can expand using add-on Booster Packs that utilize a common 20-pin interface. For the new value-line parts, the company is running a special promotion through the end of 2017, making its MSP-EXP430FR2433 Launchpad kit available on its web store and from distributors for the special price of $4.30 (regularly $9.99).

Code development for the MSP430 series has the support of TI’s Code Composer Studio IDE, which is available in standalone or cloud-hosted versions, as well as the IAR Embedded Workbench IDE. The company will also support the Energia development platform to simplify the porting of native Arduino programs to the MSP430 MCU family.

The use of a low-cost microcontroller to replace fixed-function ICs has two significant advantages. The first is that its use reduces the cost and hassle of maintaining an inventory of single-purpose parts. This replacement helps simplify design as well. The second advantage is the ability to customize operation. With many fixed-function devices, the developer must work around capacity limitations and slight mismatches between stock function and their specific needs. Replacing the device with an MCU, however, allows the developer to optimize the function for things like timing, capacity, sequencing, and other small but essential details. It also adds a degree of intelligence to the function. A color-mixing LED driver, for instance, can be configured to offer more than simple on/off or brightness control. A developer could add smart functions such as a “blink 20 times” command to offload the host MCU from such trivial tasks.

In many cases, of course, fixed-function devices are totally suited to the application need. When things are not quite right, however, or no suitable device is available, use of an inexpensive MCU to take up the slack can save developers from a significant challenge.