Supervisory system’s designer and the manufacturer has hoped the micro controller can provide the general function which for the daily surveillance application increases unceasingly, including uses electricity satisfiedly aspect and so on measurement, automobile monitoring, data gathering and sensor adjustment requests. maxq3120 is to satisfy the low power loss which, the high speed micro controller these requests develop. Its major technique standard is as follows.
•16, each second 8 1,000,000 instruction (8mips), monocycle risk nucleus •32kb dodges saves (the flash memory) • 512b ram •Has independent baudrate producer’s 2 uart •3 timers, 1 supports pwm d/a • Infrared communication function •May actuate 112 section of lcd the controllers • The dependence battery backup, has the calendar and the Asian second alarm clock function real-time clock •16 x 16 monocycle multipliers and 40 accumulators •2 16 precise modulus switch (ADC)
What tasks does the following introduction and simulate i/o and the DSP function using the maxq3120 micro controller’s above characteristic may complete some.
Pronunciation record subsystem
Concept: For group of Engineer piece of adc, they will discover how to use it to record the pronunciation. But, except the simple record sound, maxq3120 can also handle many matters. Take maxq3120 as the core, the coordination user interface part and inexpensive nand dodges saves, may construct a function perfect pronunciation record subsystem.
Detail: May realizes audio frequency i/o using maxq3120 adc and the pwm timer. the adc fixed input voltage is 1v to - 1v, its built-in Pre-amplifier’s programmable gain may reach 16. Usually, has the built-in impedance matching electric capacity type sound pick-up to be possible the direct connection adc input end. If needs to lower the noise or the high gain, may use maxim Corporation’s Pre-amplifier max4467, this amplifier can provide the bias which for the sound pick-up needs, and provides the power loss extremely low shutdown pattern for battery power supply’s application. In the out-port, actuates the speaker with a single stage amplifier, this amplifier simultaneously also has certain anti-aliasing and the pwm smooth function.
After the tonic train signaling transforms the digital signal, must carry on the compression and the memory, prepares the replay. the 8mips handling ability enables maxq3120 to have “the horsepower” to deal with many commonly used standard speech coding duty enough. This domain “the golden rule” is itu the g.711 code, its working speed is 64kbps, each second transmission and receives 8000 8 sampling. itu the g.711 code has two kind of different transfer functions, uses for is 8 arranges 12 sampling value transformation the symbol. These two kind of functions are the usual so-called a law (mainly use in Europe) and µ the law (mainly use in the US).
If expected that a higher compression ratio, may sacrifice some voice quality, uses itu the g.726 code. the g.726 code uses the auto-adapted difference PCM (adpcm) plan to carry on a higher efficiency to the voice signal the code. This kind of code support many kinds of rate, lowest are 16kbps. To the majority applications, this code request processing speed is not bigger than 3mips. itu g.711 and itu the g.726 code only needs very few ram. In the recording stage, timer every 125 µ s (under 8mhz clock rate every 1000 processor cycle) has an interrupt request, after the microprocessor response interrupt, calculates sampling value mean value which obtains in the previous timer cycle (two or three sampling, adc an every 48 µ s sampling time), with the aim of obtaining the 8khz sampling rate which needs. Afterward, gathers 16 sampling may use the designation the code scheme to carry on the code. When playbacking, after sampled data by linearization, delivers the pwm controller, actuates the speaker.
After the compression voice data may use in saving, but the maxq3120 micro controller dodges besides the procedure saves not other memories, therefore needs the exterior memory to save the pronunciation data. Is nand dodges regarding this application performance-to-price ratio highest exterior memory saves, its capacity may reach 8 lucky positions. Regarding the 16kbps code, this kind of component may provide surpasses 6 day-long pronunciation memory. But, nand dodges saves is imperfect. First, majority nand dodge saves the component to have one “the slight defect chart”, tells application software’s to have “the bad spot” in memory array where the existence. Next, looks like other may clean the memory to be the same, after long-term use, nand will dodge some units which will save to lose the memory property. What is lucky, nand dodges these flaws which saves to the pronunciation application influence not to be big, does not look like to application and so on solid state floppy disk influences is so big. In the pronunciation application, nand dodges these flaws which saves to be possible to neglect, they most cause in the pronunciation to have the instantaneous disturbance.
Regarding the capacity so huge pronunciation memory, must carry on the effective store management. This work completes by system’s user interface part, the user interface part’s core is the lcd controller. It can actuate on 4 public surface 28 sections of demonstrations, the maxq3120 lcd controller compatibly in massive existing 3v the lcd glass. May the very low cost obtain the lcd module which has custom-made.
The user may through connect maxq3120 the general i/o port’s button to control the pronunciation recording system. maxq3120 has 4 8 general i/o ports and component’s other functions uses in common.
What also needs to make? MAXQ3120 uses in the high-level pronunciation recording system’s ideal micro controller. When uses it designs the pronunciation recording system, the designer only needs to complete the following work:
•Design user interface: Chooses section of lcd, determined how the displayed information, the establishment button function, how does record and the organization pronunciation data. •Chooses the sounder: Above may select one which of two itu encoders mentioned, may also select other special-purpose encoders, when the storage capacity is big enough may also the direct access voice signal primitive sampling value. Many standard encoder’s c language source codes are may buy, therefore only needs to develop the interface routine simply. •Choice storage medium: nand dodges saves is the ideal choice, but may also act according to the actual situation to choose other memories, for example, inexpensive general transportable memory (sd, smartmedia™ or mmc memory stick). Some manufacturers may also provide the memory stick connection the c language source code and the development kit. •Battery management: If the pronunciation recording system with the battery power supply, needs some form the power source management. maxim has many kinds of highly effective low power loss battery management plan. Unifies these
The plan and the maxq3120 low power loss stop and the sleep pattern, will enable the pronunciation recorder to have satisfaction battery life.
Doppler radar
Concept: Many years ago the Law-enforcing departments are using the Doppler velocity radar. If this kind of radar system’s construction cost can reduce greatly, then its use is not only restricted in copes with on these path’s overspeed. For instance, it may stops when the front vehicles remind the pilot. which can maxq3120 display in the Doppler radar system to affect?
Detail: Doppler radar’s principle of work is quite simple. The radar installation launches one continual, the known frequency micro wave beam (to rise in the US microwave frequency to the ku wave band, approximately 24.150ghz), after the micro wave beam meets the mobile target, is reflected. Because the reflected wave frequency is higher than or is lower than the transmitting wave slightly the frequency, after therefore reflected wave and transmitting wave mixing, may obtain the frequency “to pat the sound” definite by the equation below:
f = [v * (f0/c)] * cosθ
And, Nu is the testing goal speed, f0 is the fixed transmitting frequency, Theta is the target travel direction and between radar system’s included angle (e.g. chart 1a shows), c is a speed of light. Attention, if the goal treats the radar system to come directly, then θ= 0, cosθ= 1, the goal velocity of movement becomes:
v = [f/(f0/c)]
For example, if ku the wave band Doppler radar produces 1khz “to pat the sound”, then surveys the goal faces directly comes (either draws back) the speed is 12.4m/s (i.e. each hour 28 miles or 45 kilometers). Available maxq3120 processes this kind of tonic train signaling, diagram like chart 1b shows.
Chart 1a. Received signal’s Doppler shift is decided by the goal velocity of movement and the target travel direction and between radar system’s included angle.
Chart 1b. In the Doppler radar system, the maxq3120 guiding radar head, and withdraws from the radar module output’s intermediate frequency (if) signal “pats the sound” the signal.
Using two ADC channel’s, maxq3120 can the sampling radar module output difference signal, withdraw strongest frequency component, and converts it each hour kilometer or the mileage. In addition, while - adds the unit using maxq3120 also to be possible to carry on some complex filter operation, withdraws the strongest frequency component from the complex signal, and possibly withdraws the useful information from the weak signal (for instance, Doppler radar system delivery vehicles’ velocity of movement).
In many situations, user interface’s design is very trivial - - frequently is some logical processing or through the switch triggering audio frequency warning. In some applications, the micro controller also wants periodically the writing speed, as well as carries on the velocity measurement the time and the date and so on.
What also needs to make? Most factory production Doppler radar module output audio frequency if. To the simple velocity radar system, the work which is left over is simple. Regarding more complex some survey analysis system, but also needs to develop some related signal processing the algorithm. What is lucky, many may use in being auxiliary develops the filtering algorithm and the recognition algorithm outstanding tool.
Some radar system needs to instruct that the goal the heading, namely the goal is far away from or approaches the radar? The traditional Doppler radar cannot complete this work; They to speed but the direction opposite movement has the same frequency deviation quantity equally. Now, some factory production’s radar module contains two group orthogonal outputs, demodulates these two groups outputs, then may determine the goal according to theirs phase difference radar system the heading. the maxq3120 micro controller has two adc, may realize this kind of function very easily with it.
Telephone supervisor
Concept: Sometimes the people hoped that (who traces telephone’s service condition and who talked over the telephone, when passes words, telephone conversation time is how many), but is not willing to purchase expensively, the complex telephone conversation cost system. This kind of situation’s example are many. For instance, the parents want to trace child’s telephone service condition. When do the active populations want an automatic recording they to give who to telephone, as well as when who telephoned the diary tool to them. When each room telephone public telephone line, these lodging adds the landlord who (the next day) the breakfast way hires the room, hoped that has may trace the telephone service condition the system. This kind of system may cause them to charge the telephone bill quite easily to the visitor. May all telephone conversation installment (see Figure using the maxq3120 micro controller composition surveillance telephone line in 2).
Figure 2. The telephone supervisor surveillance exhales the number, to come the electricity ringing, calling id as well as picks machine the event, determined that exhales the number, the calling number as well as the telephone conversation time.
Detail: The telephone supervisor must monitor four kind of situations: The telephone line on-hook/picks machine the condition, to come the electricity ringing, the call number and the calling id information. And what simple picks machine the signal surveillance, because picks the machine-hour, the line voltage (on-hook status) becomes below 12v from 48v (to pick machine condition), the voltage detector is very easy to examine this kind to change and to inform the MAXQ3120 micro controller.
Comes the electricity ringing by the Telephone company telco the high-pressured exchange signal production which loads in the telephone line. This signal sends out the warning after the capacitive coupling and the electro-optical disconnector backward processor, simultaneously maintains with the telephone line isolation. Usually, can examine this signal reliably with 0.47 µ f electric capacity and the 4.7k resistance series connected bidirectional optical coupler. In order to avoid the misoperation, may use a pair of zener diode back to back, only then, when the voltage surpasses the breakdown voltage only then permits the electric current inflow light disconnector.
Call number’s receive is slightly complex some, because has two kinds to transmit the number to the Telephone company telco the method: Pulse digit dialing and voice-frequency dialing. The pulse digit dialing method basis dial’s digit produces 10 current pulses in each second. For the detecting pulse digit dialing, only need examine in the telephone line the voltage jump time from low to high, if presents a string jump by each seconds 10 time speed, without doubt this is the pulse type digit dialing.
But, the pulse digit dialing telephone are getting fewer and fewer, what at present is popular is the double sound multi-frequencies
(dtmf) digit dialing method. In this method, on telephone’s numeric keyboard is arranged becomes three rows four lines, see Figure 3. Presses down a number key, will produce one with the line of corresponding sound and with the row corresponding sound. Through examines and interprets the tonality the combination situation, maxq3120 may determine allocates number
Figure 3. The double sound multi-frequency (dtmf) digit dialing plan has arranged a good sound and a row sound for keyboard’s on each key.
The attention, most right side a row (a, b, c and the d key) only uses on the bureau end equipment, the client side does not have.
the goertzel algorithm is one kind suits the highly effective tonic train signaling examination method which realizes in cpu. It is double-pole filter, may examine the tonic train signaling clearly in the noisy channel. Realized this algorithm procedure on the maxq micro controller already to pass the test.
Is very easy using the calling id confirmation of service calling subscriber’s telephone number. This service’s subscriber may receives 1200bps between 1st and the 2nd ringing the signal, contains the calling number, calling subscriber’s name as well as the time and the date and so on.
In the US, the telephone company uses bell 202 modem standard transmission calling id. Europe uses the standard is itu the v.32 pattern 2 (the 1300hz mark and 2100hz blank). Two kind of standard data transmission rate is 1200bps. Simultaneously supports these two kind of standards very easily in an application, but here only discusses the standard which the US uses. In this standard, “0″ the position indicated with the 2200hz audio frequency that “1″ the position expressed with the 1200hz audio frequency. maxq3120 may examine the zero crossing spot easily, and from the specified input signaling frequency and it represents data position. The data format is very simple, for the serial asynchronous n81 form (non-parity check position, 8 bit data, 1 stop position).
After examination arriving value, must analyze the news the form. Two kind of calling id form. The first kind only contains the calling number and the date and the time. As follows shows:
If the user has only subscribed “only the number” the calling id service, uses this kind of form to transmit calling id for them. Attention, besides type, length and verification and, other characters by ascii code transmission. If does not have the calling number, uses the letter “o” generation of it. If the calling number should caller’s request forbid to transmit, uses the letter “p” to replace the telephone number. The verification and in the information front various bytes take 256 as the mold and, are 2 base complement forms for this reason.
If the user has ordered “the name and the number” the calling id service, will receive the information which as follows will show:
And, type is always 0×80, length is all block data length. The block data form is:
And, block type expression transmission data type, its value according to next table choice:
Once related some telephone conversation’s data gathering Qi Houpian may save in i2c* eeprom. This kind of component is inexpensive, is reliable, and may provide many kinds of storage capacities. 16kb eeprom can save 100 name - number form the calling id record. Realizes the i2c correspondence code on the maxq series processor with the software also to have provides.
What also needs to make? May also consider that carries on some strengthening to this system’s function. Although above discusses the plan may monitor all online telephones, but which telephone is it unable to tell you are sends out or the reply call. In order to achieve this point, on each telephone needs to install one not to need any user interface the monitoring device. maxq3120 may through the electric current sensor determine when the telephone is picked machine, and informs located at the central telephone supervisor. In order to complete this kind of communication task, in telephone’s micro controller may transmit the dtmf digital signal, uses for to distinguish exhales or the reply telephone. In on-hook status, the Telephone company telco “looks but not see” to these signals, therefore, the indoors telephone line has provided the ideal channel for these digital signal.
The strengthening on the other hand is registers automatically to a computer. the maxq3120 micro controller has the uart channel, may with the pc serial port connection, like this be possible the telephone supervisor thorough transformation to be an exquisite telephone cost system. If again and front introduced this kind of cost system the pronunciation recording system unifies, you had a very perfect responser or the telephone recorder.
Electric power monitoring device
Concept: Is the electrical bill such why high? This is the complaint which the Electricity company hears frequently. And, the partial reasons which has nothing to do with the fuel price is more and more electric appliances is at throughout consumes the electricity condition.
Do not complain the electric refrigerator, because its power source is the intermittent switch, only then, when electric refrigerator’s internal temperature is higher than the limitation value the power source is put only then through. In fact, consumes the electricity the equipment everywhere is. Thinks in the multimedia equipment to send out the bright the indicating lamp, tells you it to close, waited for that your guidance command opens it. In the past, “switched off” the switch to mean that this equipment no longer had any form work. But in today, switches off the television is only causes it to be in the waiting pattern, many electric circuits were still consuming the electricity. In fact, already was very now difficult to find the true dump’s electric appliance.
The microcomputer is also the hiding consumes the electricity the equipment. In now on-line time, the people leave when also lets microcomputer downloading document, collection mail and so on. How many electrical bills can it spend?
In this last part, MAXQ3120 returns its source, but the role transforms into using electricity, but no longer is the power supply. Figure 4 showed this application diagram.
Figure 4. Uses electricity the monitoring device to be able to determine when some electric appliance has used the how much electricity. It may also the public lecture damage sensitive equipment’s voltage surge and the power failure breakdown.
Detail: maxq3120 designs specially for the support electric instrument application. Its two ADC designs separately uses in monitoring the voltage channel and the electric current channel. In this project, the maxq3120 continuous monitoring enters some equipment’s voltage and the electric current. Then,
It may report that this equipment’s average power, uses electricity the number of times which and the scope the peak appears, as well as, if needs may also provide this equipment’s power factor.
How to report? The simple, the direct method are use exquisite lcd in the monitoring device. May use or many push-button control maxq3120 cuts (voltage root-mean-square, electric current root-mean-square, power, number of degree in many kinds of display modes and so on). the lcd price is extremely inexpensive, uses for to monitor time the single equipment, may do is compact easily, to use.
If must monitor many equipment, may construct a central station to record from respectively from the data which stands. This project’s difficulty lies in the usual feed circuit uses when the data transfer medium the quality to be too bad. Is unable with the inexpensive module to realize the ideal data transfer rate.
But, may use the inexpensive module to realize not too ideal data transfer rate. maxq3120 adc only has 20,000 time/second sampling speeds, this speed is unable to demodulate in the 100khz scope the carrier (this frequency band to use in generally power line control system), but they may demodulate the audio frequency scope the carrier. If the data transmission rate is slow enough, compared to 10bps, may realize the very reliable correspondence as promised.
Like this besides monitors the electric power, the maxq3120 DSP function must complete other two work: The surveillance from two narrow band’s signal powers, and attempts examines the low speed frequency-shift keying (fsk) signal; If receives the request, but must transmit 3khz for the master station to the 7khz fsk signal.
The master station may be the independent installment, may also through microcomputer’s serial port and its connection. The latter kind of plan has the attraction, because microcomputer’s reserves is big enough, and can complete compared to a micro controller more complex duty.
What also needs to make? What also needs to make? Are not many. May apply for the complete electric instrument reference design (zip, 76kb), after undergoing the simple revision, may use in this project. About the power line correspondence, used in the signal producing may also find with the bandpass filter’s maxq3120 code. Therefore, only need in then be possible with ease to construct together these part conformity a low data rate fsk modem. In short, through simply the conformity existing hardware and the software element, may compose the product which may work.
Conclusion
Through these application example we may see that besides takes the multi-purpose electric instruments the cores, the maxq3120 micro controller also has bright prospects. The formidable function enables this model of micro controller to have the expansion opportunity in many application domains, possibly is your next composite signal project ideal plan.
