[...]... discussion, hard processes are defined as direct physical-world interaction tasks where timing and system robustness are likely to be critical to performance and/ or safety Examples in the E-2 system are: Stepper motor control for rudder and dive planes, battery charge and thermal monitoring, depth monitoring, propulsion motor control, and bilge sensors Hard processes are typically easy to identify and characterize... components—maybe even an undocumented ASIC 10 Microcontrollers, Single-Board Computers and Development Tools In a similar manner to the way I handled task management, I divide system communications into two classes; control- critical and noncritical In the case of E-2, all control- critical data transfers occur within the vehicle itself, between the various real-time modules and the main controller These communications... of the standard ITX board used in desktop PCs, and it has a connector for a standard Some vendors still sell systems based around older x86 processors—80186-compatibles are quite common—but we won’t discuss these 22 Microcontrollers, Single-Board Computers and Development Tools ATX power supply Mini-ITX implementations extant at the time of writing require +3.3 V, +5 V and +12 V rails ■ Standard-sized... precisely, and can often be implemented in a small 8-bit microcontroller In the E-2, we will perform all the hard tasks using microcontrollers in the AVR series, from Atmel By contrast with hard processes, soft processes are not at all mission-critical, and have relaxed or nonexistent real-time requirements Generally, soft tasks can crash, provide erroneous, untimely or downright missing data, and the... punctuation In common with most other technical publications, sourcecode and command line text that is intended to be typed verbatim is rendered in a fixed-space font Occasionally, you will find UNIX commands and library functions mentioned with the standard nomenclature of command(n), where n is the section containing the manual page for the command in question For example, you can find out more about rdev(8)... whatever media and protocols are convenient, with less attention paid to real-time issues such as lag2 You may wish to pause here and consider the implications of the preceding decisions In particular, note the implication that hard tasks and control- critical links are trusted and soft tasks and noncritical links are not trusted We’re going to be running all the hard, critical stuff in small microcontrollers... that conceptually, the same bugs and design shortcomings will exist whether a particular set of features A, B, C are implemented on one processor or three individual processors Keeping the three functions physically separate prevents them from interfering in each others’ address spaces, and also allows fast system recovery—because if, say, processor B crashes, processors A and C can continue to operate... Winbond, Cypress, and Dallas/Maxim are just a few of the vendors with standard 8051 parts; dozens more have 8051-cored ASICs and ASSPs), and the basic architecture is familiar to most embedded engineers There are numerous high-quality tools and reference designs, and megabytes of sample sourcecode available The main reason I have chosen to avoid the 8051 family is because of the lack of standardization... USB, on-chip A/D and D/A converters, expanded ROM or RAM, in-circuit programming, etc It also means that, in a modular design where each microcontroller has minimal duties, you will likely be spending far too much on over-specified microcontrollers For instance, you don’t need kilobytes of RAM or ROM for a simple stepper motor controller! 14 Microcontrollers, Single-Board Computers and Development Tools... microcontroller is primarily ease of development, followed closely by cost There are numerous readily-available RISC-cored system-on-chip devices (and SBCs based on these parts) which would have adequate processing performance for the E-2 project, and MUCH leaner power requirements However, the SBCs based on these devices are, by and large, very low-volume, expensive appliances, and developing for and . class="bi x0 y0 w0 h1" alt="" Open-Source Robotics and Process Control Cookbook This page intentionally left blank Open-Source Robotics and Process Control Cookbook Designing and Building Robust, Dependable. this Book and What You’ll Get From Reading It 1 1.2 Target Readership and Required Skills and Tools 5 1.3 Conventions Used in the Text 7 Chapter 2: Microcontrollers, Single-Board Computers and . systems and compare the cost and setup complexity of these fixtures with the relatively low cost and setup time of a simple Linux-based SBC controlling the same pneumatic actuators and sensors.