125 results found, displaying items 81 - 100

Interfacing a central processor to a user front panel is usually accomplished in one of two ways. The first method involves a power and a serial data link (typically RS-232), which are routed from...

Multiprocessor architectures have become commonplace embedded applications these days. The processors often are interconnected via simple asynchronous serial links. These links employ UARTs that...

In applications requiring absolute accuracy in the speed control of dc servo motors, there’s no substitute for the traditional tachometer-based feedback loop. But for somewhat less demanding...

In many embedded systems, it’s desirable to have modem connectivity to the controlled device. Also desirable is the ability to communicate to more than one device within a facility using only one...

Frequency tolerance is one of the most important parameters of a crystal. Determining the tolerance by measuring the crystal frequency directly isn’t always convenient, particularly for...

Some applications, such as communications, fault-tolerant computer systems, and networking, require circuit boards to be inserted into a backplane without turning the power off. The bulk supply...

A recent project requirement specified the need for a special indicator to show whether a security switch was used during the time the system was powered off. Because our system has a real-time...

With eight general-purpose I/O lines and a regulated 5-V output, the BASIC STAMP 1 (created by Parallax, Rocklin, CA) can easily be interfaced to a standard smart-card connector (...

Graphics LCD modules, such as those incorporating the Toshiba T6963C controller are attractive, cost-effective output devices for microcontroller-based systems. When used with low-cost devices...

Because of their small size, low cost, and advanced functionality, the PIC12CXXX family of microcontrollers developed by Microchip are an attractive design element for embeddedcontrol...

One way to generate a sine wave is to pass a square wave through a low-pass filter. The high-order harmonics will be filtered out, leaving only the fundamental. The higher the order of the filter, the purer the sine wave produced. The MAX292...

When designing synchronous digital systems with data paths, registers possessing a synchronous clock enable are needed. Use of standard off-the-shelf parts also is required. Unfortunately, few of the standard registers have a clock enable capability....

In a low-cost microcontroller-based design, it's possible to generate the negative voltage supply required to bias extended-temperature character LCD modules without a dedicated voltage inverter IC. Using fiv inexpensive general-purpose npn switching...

The circuitry shown in Figure 1 demonstrates the technical features from both phase-locked-loop (PLL) and direct-digital-synthesis (DDS) designs. The design represents a phase-locked oscillator with...

When working with low-end microcontrollers like the Motorola MC68HC705J1A or the earlier ’K1, some features available on larger chips, like selectable “full speed” and “standby” clock oscillators, are sorely missed. This circuit idea arose from a need...

The design presented here provides a simple method for controlling process variables such as temperature, pressure, flow, etc., via user-selectable control functions (e.g., proportional, integral, and differential). The PAL chip 16L8 is programmed to...

In applications that require wholeboard power cycling or actual board “hot-swapping,” maintaining a highimpedance interface at power-off as well as the power-up and power-down cycles becomes a critical design problem. Ideally, system designers can...

A classic scheme for precision temperature control is the proportional-integral or “P/I” algorithm. In this method, the heater control equation consists of two terms. One term (“P”) is proportional to the instantaneous error differential between...

Here’s an Idea For Design that’s more Idea than it is Design. Using inexpensive memory devices, you can construct a voltage, current, or count sensing system that can be permanently programmed for one set of input conditions or...

The C program presented will generate gated-digital sine waves at a 10-Hz frequency (see the listing). Three parameters are user-defined at the head of the program—the output frequency (FO), the sampling rate...

• Easily Convert Decimal Numbers To Their Binary And BCD Formats
• Bidirectional H-Bridge DC-Motor Motion Controller
• Microcontroller-Based Sine-Wave Generator Has Crystal Accuracy
• What's All This P-I-D Stuff, Anyhow?
• Inside iPod