Circuit Cellar uses an assortment of print and electronic content-delivery platforms *CES ; Embedded World based format, printer-ready PDF. Circuit Cellar is the premier media resource providing critical information on embedded electronics be submitted in a vector-based format, printer-ready PDF. Thank you for your interest in Circuit Cellar magazine! Choose your subscription method below. View a sample issue - click here. To pay by check - Include the.
|Language:||English, Spanish, Arabic|
|Genre:||Business & Career|
|ePub File Size:||28.70 MB|
|PDF File Size:||13.43 MB|
|Distribution:||Free* [*Regsitration Required]|
You can download the archive of Circuit Cellar mazagine free. You can download Circuit Cellar magazine (issues of ) free. Free package of programs to work with pdf and djvu files can be downloaded here. Circuit Cellar is a registered trademark of Circuit Cellar, Inc. Disclaimer Circuit for this issue are available: ftp://subiecte.info subiecte.info, subiecte.info
Thuy Nguyen Xuan. The scale factor shrinks to There are processor. Since the peak ring voltages sometimes weight. Circuit Cellar INK.. In the Component Coordinator.
Free Circuit Cellar magazine February Free Circuit Cellar magazine January Free Circuit Cellar magazine December Free Circuit Cellar magazine November Free Circuit Cellar magazine October Free Circuit Cellar magazine September Free Circuit Cellar magazine August Free Circuit Cellar magazine July Free Circuit Cellar magazine June Free Circuit Cellar magazine May Related categories Free Elektor Magazine Offers.
Log In. Shop Blog Forum Support. It uses repetitive subtraction rather than division. AT and compatibles and temperature conversion specified. The routine takes two readings if the first is eero. This is one place where readings can be dropped while waiting for room in the utilities Runtime library.
This method ensures completion in a finite time regardless of the magnitude of the values being calculated. It detects end-of- line characters CR and LF. Communication Parameters Commands C. This will automatically set up the specified channel for periodic readings by the scheduler. Time in entered in hour format with 1 or 2 digits for hours. If the time has never been set. If the value is or Read the specified channel once immediately.
C is enabled by any noneero value and disabled by a tero. The interval mode. Channel-Specific Commands D. If you have installed a 1O: A value of 1 sets the parity bit to 1. Default Echo the input characters back to the terminal. When the sampled voltage goes back within the limit range.
Only the currently active parameters will appear on the status line. A value of 0 specifies normal voltage readings. Any value given is ignored. A reading that is higher than this will be displayed. A value of 3 converts it to temperature in Kelvin. Any value. The channel number. The channel parameters are NOT modified by this command.
A value of 1 converts it to temperature in degrees Celsius. The value may be entered with a decimal point which will be ignored if desired. Table 2. A value of 3 sets the parity to odd parity. A reading that is lower than this will be displayed. Both the channel number and value. Default is sero parity i. Default output a linefeed as well as a Carriage return at the end of each line. Initial Setup Commands A. If the value given is 0.
Setting the decimal point after the 3rd digit with D3 is appropriate when displaying temperatures. Enabled by any noncero value. The time clock defaults to 0 hours and 0 minutes when the box is turned on. A value of 2 converts it to temperature in degrees Fahrenheit. This command only performs the appropriate conversion math for the output value. The particular channel may be read several times by the program before a valid reading is obtained.
A value of 2 sets the parity to even. This clears any interval times. Setting DO will remove the decimal point entirely. I worked for the Forest Service in Oregon. A growing percentage of computer users have reached the point where they know their needs and prefer efficient computer solutions to overkill.
Pretty funny. The sales rep who equips a laptop with Word Perfect Executive and nothing else. I believe these people represent a small but expanding market for new approaches to computing. All it takes is a good concept and a little dedication. It was a physical. We knew that branches. Our clothing reflected the realities of this life.
With a couple of cables. Nowhere is it more common than in the computer business. They are dedicated machines. Not really. Any of these is quite satisfactory for my work as a freelance writer.
The Canon Cat boasts a flexible word processor created entirely in Forth. After a couple of dumbfounded questions.
I receive amazed stares when I explain that although I use a state-of-the-art Macintosh system for desktop publishing. All three of my systems are text-processing environments with telecommunications capability. Many consumers are moving down this path as well.
Ezra Sharpiro is a free-lance writer and publications designer based in southern California. The CPUs are different. Several factors the Weather Data Processing Sys- come into consideration when tem software expands. If you discussion and review the high. Some of specification. Memory usage horizontally and lines verti. You can really only display a since samples times lines -The original picture is essentially This time -Special signals are sent to indicate start-of- f r a m e a n d end-of- frame.
The ment package. If you sample the sion now with the routines involved signal based on the actual in WEFAX processing. For now. If so. A count of is convenient in optional megabyte. The sample time will be de. There are two steps to pro. Processing System software. This is a crystal. Once again. The timer provides for prescal- words of memory. The multiple of eight. The start signal will line divided by samples per immediately sample the WEFAX begin the sampling process.
In reality. Looking ahead to future needs. Allowing for memory used for the process. If the flags are Since the line length. The data start information. Jumpers for DRAM article for more information. MHz and An AGC-volt. The data rate. Software and m monitors for the presence of an EPROM listings for this article are audio carrier by reading the byte.
Figure 1 -. The in. The software switches provide you with enhancement in- from one unit to the other by writ. The Heath ID interface.
BBS or on Software on Disk 7. Before booting the more complicated. You complete record keeping. Cable assemblies for connection to rain gauge and humidity instrument. You also need.
The ID requires only the presence of a So far. Their intention was necessary. Weather Computers. The unit serves a number of H e a t h I D. If everything use for this purpose. CMOS micro- Pseudocode is pleased to announce the release of an extensive line o professional cross-development tools.
VA BC6. Toots that speed development o processor which contains a ROM-resident 8K microprocessor based products. Intel RCA Next time. Remove the segment driver terface from the PP. It stores the numerical data in a serted disables the incoming data The read sequence is controlled simple on-board SRAM for later lines from the ID It provides for data conversion of thing. Cdl la OEM uicim. The transfer to the PP. W sinale atv. It buffers the wind direction data The digital rain gauge and the from write mode on completion of for access by the PP.
It can be used both for development and end-use a lications. A4 negated. The data from the the interface end. The IC. Prices Mat at S They do knowledgement through the input and the separate Humidity Indica.
Rockwsll EYJoz Intel The port output strobe is ID parallel port to the inter. Putting these time saving tools out of reach of all bu boards. I take advantage are read. The BCC52 bridges the gap between large corporate engineering departments. Control Magic. Carrier Current Transmission Timing Board..
Circuit Cellar INK.. Available in February I regret Visa and Mastercard will be accepted.. AZ P. Box Vernon.. Allow 4 to 6 weeks for shipment since most of this material will ship UPS. Pricing for ISSUe 5. Data Acquisition Front-Panel Board CT Each kSue I. Box 1st Year Reprlnt Phoenix.. Issue 2. I am unable to accept credit cards. Mail orders: Send check or money order to: So as not to disappoint new subscribers as well as satisfy the addressed business-size enve.
CT Include check or money order if ordering kits. Visa and. Box Send me a stamped.. Line impedance can range from below 1 ohm to above 50 ohms. What can be strength will occur between phases of the power line. This Line impedance varies continuously. Heavy losses using the AC power line for data transmission: Whether we consider our appli. Stock diagram of the National LM with surrounding support circuitry.
Figure 1 Every time an appliance through any Hz filtering. How- ever. Data and impulse noise from the version. All of the impulse noise less than the and sending TTL serial data into pin Continuous wave CW interference is caused by current-controlled oscillator ICO which modulates equipment generating a signal at some periodic fre. Signals passed through the coupling must be chosen in the range of least interference.
Figure 2. CW interference within the range current away from the output amplifier to keep the of the selected carrier frequency will affect both the signal from clipping due to line impedance changes reception of the data and the quality of the data which would cause unwanted RFI.
The differential demodulated frequency of kHz. A sine shaper quency on the line. The Signetics NES needs a minimum of external components to support power-line- based communication. Close boosted by using a single external transistor. Communications Signetics Corporation filter. With both the LM and the NE A balanced Norton-input n amplifier removes the DC offsets. Only data will toggle the open- I collector output.
Refer to articles on packaged in a pin chip. A 99 I Gilbert detector compares the in-phase signals. CT rl6fI66 and maximum data rate. How much capability. RX OUT. Submit to: The AM rejector tracks Semiconductor Dr. Box to that of the detector capacitor. This external circuit can be as simple as a East Arques Ave. Signetics NE collision. Please share your favorite ideas. TTL checking or error correcting protocol. The example tion packages can send files with some type of error circuit shown in Figure 2 uses ASK modulation.
CA supplies a constant current to the impulse capacitor. Each manufacturer fully covers com- ponent selection and typical application examples in their respective data books. Two volts of As little as mFIS sufficient to kill a human being. The externally Sunnyvale. Do costs compare favorably to alterna- Signals passed through the coupling transformer are tive systems? How fast? What is the line The receiver of the NE is always active. CA filtered signal reenters the NE at pins 4 and 5.
It will receive its own transmissions. Any node can access the line Moderately Useful to transmit signals at any time. Box arrangement using ceramic filters. Most telecommunica- amplitude shift-keying needs but one.
Exercise extreme caution when using either device described here. Since data bit errors are related to noise mode. The NE can use an optional external Whether or not PLM communication is practical complementary transistor pair for increased current for you will depend on a number of factors. FSK modulation requires data rate goes up. Include a stamped. Any capacitors wired on the per line side of hysteresis ensures that the impulse noise will not affect the arcuit can retain a charge even after power has been removed from the circuit the SR flip-flop.
The comparator Santa Clara. Rule of Programming: The door switch task evolved specifically to support to the magnetron subroutine. A will respond with a blank stare. PDP sysops will begin ous door switches and other safety oven. Like Quantum Mechanics. In this case only a Real-Time have to pulse a one-shot line to the Operating System will clean up the control circuits. The RTOS of mainframe and mini systems. Since the system is hope- mainframe operating system in that of hand.
Add yet more code most trivial. In the case of the microwave VMS. The ture and device controllers which oven is on? Have the magnetron magnetron routine can run once a invariably seem to be bypassed in routine check the door switch. The qualify as an OS. An inexperienced programmer keypad driver is another. Add a keyboard keypad task should run rather fre- DOS can handle only a single pro.
It differs from a subroutine seems to be getting out pressed. A magnetron many microprocessor designers simple. VAX programmers may think of timer display. Did second. Since many tasks tasking operating system is that The RTOS itself resides in low are competing for time. This is called for execution i. The operating system itself consists anxiously awaiting CPU time from quence tasking. Figure 1 is computer time is a valuable re.. The arrows included on the board. A number of subroutines only one task can be active at any interrupts to signal their readiness can be called by application pro.
Rather onds. The context switcher cannot reality. The context switcher is aware of time. Time Operating Systems to satisfy tant event occurs. WAITing and sched. To shared between many activities. This can only central nucleus of the RTOS. The circles represent each of memory for an 8-bit system is tasks.
The built-in mem. A tremendous amount starting. Switch execution time be. Every time this interrupt task control block TCB for the than execute a null loop. It The BCCl80 is the ideal plat. Allow tasks to alter their is not immediately a contender for have introduced commercial Real.
This task may not start state for specified periods. It is programmed by Tasks are initially defined us- belongs. Its processor the previously described functions. TIVE circle for the entire picture. RUN -. After the delay though the commercial products a real RTOS. Provide a mechanism states: The task is includes the timer needed to se.
Since to occur. CPU time to tasks in IO-ms chunks. To me. The grams to request task servicing. To the RTOS. In recent years several vendors -. David Baker Assoc. Once canceled.
TIVE and start running? After all.
When a tic feel our material rate5 with you. Camp Consult. Zi How useful is this article? If more than one task is eligible for execution. MD attempts to run the next sequential tached card. EST -. Your source code ant but exactly how does the context Micromint. Give us 2 more eligible than others. Chrysalis Micro. This is set to the RSI operating systems. It alternates execution between the Task 0 is never explicitly created.
Many tasks may be elapsed. All scheduling information and han- MUST execute every so many tics. In a real-time actually first examines the current byte entry for each task. The Round Robin scheduling 8 Wait count. Careful de. Task's reschedule interval. Why would you want a task to eligible task. Legal values are 1 to Be sure that they exit.
The are eligible and that have equally The first TCB entry is assigned display task might run at an ex. Task's priority.
Task's reschedule count. Required to support memory management described for the longest amount of time. It is and then actuate a controller per. Given when the task uling. This is the BBR value for the-task. All schedul- say. Suppose a ms ously. The algorithms have priority level by issuing a call to when it really needs to.
It is much better to defined as algorithms plus data task can. This is the task's entry point. The real meat resumes the round robin concept. It pointer is always kept pointing to needed to gather data. Instead of just starting the next through it.
The next prior. Every task ms? No one will notice. Often a display is also needed. The higher the priority. Only 14 system. Control Block TCB. In other words. The display activity may high-priority tasks until they all the RTOS forces it to exist when a get suspended for long periods.
MUST use its own. If several tasks are found that algorithm. Task 0 is defined into three sections. In this way Id tcbptr. O add hl. TCB so that all subsequent calls to erating system. Id h1. This is usually the case with POP ix software. A formation. It can never be other routines will find the TCB in directly invoked by a user program. The example RTOS calls. When in0 tmdrO1. This involves rather. Llsrlng 1 cient understanding of the prob- lem.
Complete code a known. And ei reti restart task so it should be. The stack pointer ex af.
Most software disasters are attributable to insuffi. Call remap. Id' l. In the next issue. Exit the current task address given in the TCB. It contains the macros that ease access to the RTOS itself. This routine must be called before any other RTOS. Id Id bc. Xtl scheduling algorithm. Make a task known to the operating system the TCB.
Cancel a task: An 8-bit number can have range gives you steps at O- conversation turns to nu. A floating-point number. The scale the main number.
All numeric values in a com. That rather odd have one bit instruction! The value 0 1 The numbers shown in Figure calculations require real numbers hex is one volt. Because the Mandelbrot Set ues are one volt apart. Those two features are often range and precision. The array is controlled by losing any precision. Now tional group of bits to specify As Steve puts it. The trick is to pick a numeric values. Ol-volt precision you to beat when you need fast execu.
An is hard Engine work out correctly. The result can be increase by a factor of two to the evaluate the Mandelbrot Set calcu. The October through Decem. The bit values of Intel s programmed to distinct values. The scale factor located in a fixed position in each immediately to mind. To get a range never comes up when the confused. On the other calculations require high precision. The key Figure 1 shows the binary values format that takes advantage of the point is that once you know how for each input voltage.
The rep. One way to Figure 3 2: A peculiarity of signed-magni.. The usual conven.. The voltage for what the does naturally. Note that there are two ways to represent zero volts. There are several ways to rep.
Perhaps 0. In real life. The distinction between report that zero is not equal to zero. Voltage step size The only effect is that there is one Note that after the rep- get better resolution we must re. The overall range is Figure 4 shows the correspond. The scale factor shrinks to In order to 0. Increasing digital values correspond ing.
Figure 5 shows the because the Mandelbrot Engine number of bits. The negative voltages still complement scheme lets us have times as many steps within the start at Those eight bits can represent analog voltages. There are 64 bits. If you need a very numeric format used in the Man. I picked this order because it makes tion.
The answer for this is of two bytes requires more than in each number. You can try adding some process is done and the result fits of the values in Figure 4 to see if Extended Arithmetic within two bytes. The 1 can only add num. The ALU can also All extended-precision num. You might wonder what hap- mathematics. The ADDC instruction. The remaining steps adjust the Figure 5 -. Because of the nature of the and adding columns from the right.
Performing mathemati. The addition of the high-order two a bit result. The There is one slight problem. Those two opera. The fixed-point representation used in the Mandelbrot pointers to the next bytes remem- Engine uses bit munbers.
Mandelbrot Set calculations any If the sum of any column exceeds ers from the high bytes to the low number larger than 4. OOFS during debugging. First it adds pens for negative numbers. The constant ceeds the allowable maximum by signals when the sum or difference NUMLEN is the number of bytes one count. What happens when two the difference between fixed-point point to the most-significant byte numbers add up to more than numbers and rather long integers.
The key to extended-precision numbers is shown in Listing 1. The result is overlaid on the range The routines that column. Extended-Precision Addition The multiplication routine can ing. Return6 RO and RI unchanged bytes.
A over the same number in the prod- MOV B. At first 00 00 00 F8 glance you might think that the 00 00 process is just as simple as addition Aligning the binary point Long Multiplication 0.
OD 90 byte multiplications. Rl points to the high byte of the source: Mashes A and B ply ignore the high-order two. ADD A. The four high-order leftmost bits are discarded.
Fig- ure 6 b shows this process. Add two long integers expected it to fit into 16 bits. Figure 6 a shows the intermediate steps re. The first figure shows a problem inherent in multiplying quired to do this by hand. Figure 6. We compromised: It takes effect multiplier bytes and the other to on the contents of the low-order 12 after the partial product for the handle all the multiplicand bytes on bits.
A because of licensing agreements. The high-order four bits can low-order multiplicand byte is every pass.. The multiplier is located in the buffer at mpy0 through mpy7 Embedded in each multiplication is and is replaced by the partial products. The remain. Rub remaining multiplier bytes across multiplicand subtraction. MOV B. The byte product buffer is defined by these macros: RO points to the multiplicand. Listing 2 shows the core of the loops.
The alternative is simple: III covers July through December IV awels JanuaryfhroughJune Serve After a Although the ready availability what would you like to see for the good deal of tinkering and fiddling of math coprocessors makes float. VI covers Januaty through June For projects needing one way or another drop a letter. There are processor. C4 on Reader Service Cord. Suite Binary Technology. You may find that floating a full-blown DDT project.
Box l Memory: Send your project outline to: Writing technical articles may not make you rich and famous but it might be just the incentive to finish that 1 OO-MIPS computer you started last summer. II covers December through Call n o w! For about Engine can compute one iteration many PC projects. Unlike most narrowly specialized publications. TBBS 2.
Stay tuned. If Byte 1 -. The best is yet to come. Processors located around the come by. Now you can spend time off-line of a two-way LAN around and wondered if you have implemented without the clock ticking to prepare a thought-out anything special in your systems that might be important. Version 2. Packet Length interested in files uploaded since your last call. I have been rolling the requirements prepared off-line. See page 62 for details. More protocols have been made system.
Addreaa Byte 3 -. To keep fibering my term for wiring. Now it ir at a simple but powerful and useful level. For packet. I have message. Command will show you a list of files it contains.