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The AVR chips all have internal hardware that can be used. For this description of the hardware the 90S8515 was used. Newer chips like the Mega8515 may differ and have more or less internal hardware. You will need to read the manufacturers data sheet for the processor you are using to learn about the special internal hardware available. Timer / Counters The AT90S8515 provides two general purpose Timer/Counters – one 8-bit T/C and one 16-bit T/C. The Timer/Counters have individual pre-scaling selection from the same 10-bit pre-scaling timer. Both Timer/Counters can either be used as a timer with an internal clock time base or as a counter with an external pin connection which triggers the counting. timer-counter prescaler
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Now we come to the most popular application of the diode: rectification. Simply defined, rectification is the conversion of alternating current (AC) to direct current (DC). This involves a device that only allows one-way flow of electrons. As we have seen, this is exactly what a semiconductor diode does. The simplest kind of rectifier circuit is the half-wave rectifier. It only allows one half of an AC waveform to pass through to the load. (Figure below) Half-wave rectifier circuit. For most power applications, half-wave rectification is insufficient for the task. The harmonic content of the rectifier’s output waveform is very large and consequently difficult to filter. Furthermore, the AC power source only supplies power to the load one half every full cycle, meaning that half of its capacity is unused. Half-wave rectification is, however, a very simple way to reduce power to a resistive load. Some two-position lamp dimmer switches apply full AC power to the lamp filament for “full” brightness and then half-wave rectify it for a lesser light output. (Figure below) Half-wave rectifier application: Two level lamp dimmer.
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- circuit
- diodes
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(و 28 مورد دیگر)
برچسب زده شده با :
- circuit
- diodes
- full- wave rectifier
- full-wave
- half-cycle
- half-wave rectifier
- mainland
- measure
- oscilloscope
- output voltage
- polarity
- power supply
- products
- rectification
- rectifier
- rectifier circuit
- rectifier circuits
- rectifiers
- ripple
- secondary winding
- signal
- suppliers
- the bridge
- three phase
- thyristor
- transistors
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- voltage
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Analog to Digital Converter (ADC) on ATMega8535
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ATmega8535 provides the ADC with a resolution of 10 bits. ADC is connected to 8 channel Analog Multiplexer which allows formed eight single-ended input voltage is ADC0 to ADC7. Can also be configured into seven differential input channels with ADC1 as the common terminal and the other negative as a positive voltage input. Or a second differential input channels with a choice reinforcement (gain) 10x or 200x, ie ADC1, ADC0 and ADC3, ADC2. the use of ADC atmega8535 ADC has an analog supply voltage pin separate AVCC. AVCC voltage is ± 0.3V of VCC.-
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- analog to digital converter
- atmega
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potentiometer as a sensor of water level elevation When the water level changes, the float will drop following the water level.this causes the potentiometer rotates.This system is designed to detect water levels from 0 to 10m.when the water level is 0 meters, then the potentiometer resistance is minimal (0 ohms) and maximum (10 kohm) when the water level = 10 m. Changes in these constraints will lead to changes in the potentiometer output voltage.so that, if used linear potentiometer type, then the water level changes will be proportional to the potentiometer output voltage.to be more accurate, use an amplifier to strengthen this voltage and then processed by a microcontroller. The use of a potentiometer for controlling the position is quite practical because it requires only one excitation voltage and usually does not require complicated signal processing.Use of potentiometers in particular weaknesses are: Rapid wear due to friction Noise, especially when changing position and when there is loose contact Susceptible to corrosion Sensitive to impurities linear potentiometer as a sensor
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- level sensor
- liquid
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(و 23 مورد دیگر)
برچسب زده شده با :
- level sensor
- liquid
- liquid level
- measure
- position sensor
- potentiometer
- pressure
- pressure sensor
- pressure sensors
- products
- pulley
- sensor
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- tank level
- temperature sensor
- the resistance
- the user
- ultrasonic level
- voltage
- waste water
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- water level sensor
- water level sensors
- wind direction
- wind speed
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All AVR ports have true Read-Modify-Write functionality when used as general digital I/O ports. This means that the direction of one port pin can be changed without unintentionally changing the direction of any other pin with the SBI and CBI instructions. The same applies when changing drive value (if configured as output) or enabling/disabling of pull-up resistors (if configured as input). Each output buffer has symmetrical drive characteristics with both high sink and source capability. The pin driver is strong enough to drive LED displays directly. All port pins have individually selectable pull-up resistors with a supply-voltage invariant resistance. All I/O pins have protection diodes to both VCC and Ground as indicated in Figure. input and output port in avr atmega 8535 All registers and bit references in this section are written in general form. A lower case “x” represents the numbering letter for the port, and a lower case “n” represents the bit number. However, when using the register or bit defines in a program, the precise form must be used. For example, PORTB3 for bit no. 3 in Port B, here documented generally as PORTxn. The physical I/O Registers and bit locations are listed in “Register Description for I/O-Ports” on page 63. Three I/O memory address locations are allocated for each port, one each for the Data Register – PORTx, Data Direction Register – DDRx, and the Port Input Pins – PINx. The Port Input Pins I/O location is read only, while the Data Register and the Data Direction Register are read/write. In addition, the Pull-up Disable – PUD bit in SFIOR disables the pull-up function for all pins in all ports when set. Most port pins are multiplexed with alternate functions for the peripheral features on the device. How each alternate function interferes with the port pin is described in “Alternate Port Functions”. Refer to the individual module sections for a full description of the alternate functions. Note that enabling the alternate function of some of the port pins does not affect the use of the other pins in the port as general digital I/O. General Digital Input-output Each port pin consists of three register bits: DDxn, PORTxn, and PINxn. As shown in “Register Description for I/O-Ports” on page 63, the DDxn bits are accessed at the DDRx I/O address, the PORTxn bits at the PORTx I/O address, and the PINxn bits at the PINx I/O address. The DDxn bit in the DDRx Register selects the direction of this pin. If DDxn is written logic one, Pxn is configured as an output pin. If DDxn is written logic zero, Pxn is configured as an input pin. If PORTxn is written a logic one when the pin is configured as an input pin, the pull-up resistor is activated. To switch the pull-up resistor off, PORTxn has to be written logic zero or the pin has to be configured as an output pin. The port pins are tri-stated when a reset condition becomes active, even if no clocks are running. If PORTxn is written a logic one when the pin is configured as an output pin, the port pin is driven high (one). If PORTxn is written a logic zero when the pin is configured as an output pin, the port pin is driven low (zero). When switching between tri-state ({DDxn, PORTxn} = 0b00) and output high ({DDxn, PORTxn} = 0b11), an intermediate state with either pull-up enabled ({DDxn, PORTxn} = 0b01) or output low ({DDxn, PORTxn} = 0b10) must occur. Normally, the pull-up enabled state is fully acceptable, as a high-impedant environment will not notice the difference between a strong high driver and a pull-up. If this is not the case, the PUD bit in the SFIOR Register can be set to disable all pull-ups in all ports. Switching between input with pull-up and output low generates the same problem. The user must use either the tri-state ({DDxn, PORTxn} = 0b00) or the output high state ({DDxn, PORTxn} = 0b10) as an intermediate step.
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In this article will discuss the use of DST-128 AVR Stamp. further discussion we need to know the specifications of the DST-128 AVR Stamp. dst avr stamp • 128 Kb Flash PEROM • 4Kb EEPROM • 4Kb SRAM • On Chip Analog Comparator • 8 Channel 10 bit ADC • 2 8 bit PWM • 6 PWM dengan resolusi programmable (2-16 bit) • Dual Programmable UART • SPI Interface • Programmable Watchdog dengan On Chip Oscillator • Adjustable VREF ADC • 53 bit I/O • Power On Reset dan Programmable Brown out detection • Internal Calibrated RC Oscillator After knowing the specifications of the DST-AVR Stamp, we will discuss The first application discussed is the use of timers. in each application, such as the indicator to indicate the program is running, as well as reference time for the application. And the most simple application is a digital clock. This application will make PORTC bit AVR ranging from 0 to bits 7 blinks every 2 ^n bit number, which blink on bit 0 is 0.5 ms. So if the second bit will be blinks every 2 ^ 2 or 4 * 0.5 mS then at the bit to two flashes every 2ms. timing can run correctly then the timer interrupt will be generated every Timer used for this application is the timer "1". • Normal Mode • Compare Mode • Fast PWM Mode • Phase Correct PWM Mode • Phase and frequency correct PWM Mode For this application the timer operates in normal mode where the timer will count ranging from 0-65535. Timer 1 prescaler which has several functions to dividing the crystal frequency where the frequency of this crystal will be used as a source of countdown timer. Piece of program to set the timer registers as follows: TCCR1A=0x00; TCCR1B=0x04; // Timer/Counter 1 initialization // Clock source: System Clock // Clock value: 46,875 kHz // Mode: Normal top=FFFFh // OC1A output: Discon. // OC1B output: Discon. // OC1C output: Discon. // Noise Canceler: Off // Input Capture on Falling Edge // Timer 1 Overflow Interrupt: On TCNT1H=0xB7; TCNT1L=0x1B; // Timer/Counter 1 initialization value ICR1H=0x00; ICR1L=0x00; OCR1AH=0x00; OCR1AL=0x00; OCR1BH=0x00; OCR1BL=0x00; OCR1CH=0x00; OCR1CL=0x00; // Input Capture Interrupt: Off // Compare A Match Interrupt: Off // Compare B Match Interrupt: Off // Compare C Match Interrupt: Off For more details, see the datasheet. The timer will tick every 0.5ms once and will interrupt the program (temporarily stop) and run commands contained in the interrupt service routine.Piece of program below are the commands that are carried out during the timer interrupt. ISR(TIMER1_OVF_vect) { static unsigned char i; TCNT1H=0xB7; TCNT1L=0x1B; i++; PORTC=i; if(i>255) { i=0; } } For these applications led connected to PORTC. So that every time the timer interrupt not counting from 0, the initial value of necessary charging timer. Its value is obtained from 46 875 to be converted to hexadecimal numbers B71B. Previously DDR PORTC made in order to switch the output mode display. moving led
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- application
- atmega
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