Download: 8-bit Microcontroller Application Note AVR180: External Brown-out Protection
8-bit Microcontroller Application Note Rev. 1051B–AVR–05/02 AVR180: External Brown-out Protection Features • Low-voltage Detector • Prevent Register and EEPROM Corruption • Two Discrete Solutions • Integrated IC Solution • Extreme Low-cost Solution • Extreme Low-power Solution • Formulas for Component Value Calculations • Complete with Example Schematics Introduction This application note shows in detail how to prevent system malfunction during peri- ods of insufficient power supply voltage. It describes techniques to prevent the CPU from executing code during periods of low power by use of ex...
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Microcontroller Application NoteRev. 1051B–AVR–05/02
AVR180: External Brown-out Protection Features• Low-voltage Detector • Prevent Register and EEPROM Corruption • Two Discrete Solutions • Integrated IC Solution • Extreme Low-cost Solution • Extreme Low-power Solution • Formulas for Component Value Calculations • Complete with Example Schematics
IntroductionThis application note shows in detail how to prevent system malfunction during peri- ods of insufficient power supply voltage. It describes techniques to prevent the CPU from executing code during periods of low power by use of external low voltage detec- tors. These events are often referred to as “Brown-outs”, where power supply voltage drops to an insufficient level, or “Black-outs” where power supply voltage is completely removed for a period of time. Two discrete solutions are discussed in detail, allowing the user to calibrate the sys- tem requirements. A complete guide to Integrated Circuit (IC) solutions is also included. By the use of these techniques, the following can be prevented in the situa- tions described above: • CPU Register Corruption • I/O Register Corruption • I/O-pin Random Toggling • SRAM Corruption • EEPROM Corruption • External Non-volatile Memory Corruption Note that AVR® internal Flash Program Memory contents are never affected by insuffi- cient power supply voltage.,
Theory of Operation For the CPU to successfully decode and execute instructions, the supplied voltage mustalways stay above the minimum voltage level set by the chosen operating frequency. When supplied voltage drops below this level, the CPU may start to execute some instructions incorrectly. The result is unexpected activity on the internal data and control lines. This activity may cause CPU Registers, I/O Registers and Data Memories to get corrupted. To avoid these problems, the CPU should be prevented from executing code during periods of insufficient supply voltage. This is best ensured by the use of an external Power Supply Low Voltage Detector. Below a fixed threshold voltage VT, the detector circuit forces the RESET pin low (active). Forcing RESET low immediately stops the CPU from executing code. While the supplied voltage is below the required threshold voltage VT, the MCU is halted, making sure the system stays in a known state. When the supplied voltage rises above this predefined voltage, the RESET pin is again released, and the MCU starts to execute code beginning at the Reset Vector (0x0000).
Threshold Voltage It is recommended to set the threshold voltage 5 - 15% below typical VCC, to allow forsmall fluctuations in supplied voltage. The threshold voltage should always be selected to ensure that the detector will keep the device properly reset when supply voltage drops below the critical voltage required by the CPU. Care should be taken to ensure sufficiently high detector threshold voltage even in worst case situations.
Prevents CPU Register When the Detector keeps the MCU in Reset, all CPU activity is halted. When released Corruption from Reset, the CPU Registers will all be in their default state. For the duration of theReset, the General Purpose Register File contents will be preserved. Without a Detector, random CPU activity such as described in the introduction may cause the CPU Registers to get corrupted. Also see “Volatile Memory” below. Note: The General Purpose Register File contents are not guaranteed to be preserved during Reset in the AT90S1200, the AT90S8515 and the AT90S4414.
Prevents I/O Register When using a Detector to keep the MCU in reset, all I/O Registers will be kept in their Corruption default state for the duration of the reset. Consequently, all On-chip peripherals will stayin their reset state. Without a Detector, random CPU activity such as described in the introduction may write an unknown value to any I/O Register. This may cause unexpected behavior of the on- chip peripherals.
Prevents I/O Pin Random A Detector will keep the MCU in Reset, and all I/O pins will be kept in their default state Toggling for the duration of the Reset.Without a Detector, random CPU activity such as described in the introduction may write a random value to the I/O Registers. This may cause random toggling of the I/O pins.
Prevents SRAM By the use of a Detector to keep the MCU in Reset, there will be no accesses to the Corruption internal SRAM. The memory contents will keep their present contents for the duration ofthe Reset. Without a Detector, random CPU activity such as described in the introduction may write an unknown value to any SRAM location. Also see “Volatile Memory” below. Note: The guaranteed preservation of data in internal SRAM does not apply to the AT90S8515 and 4414. In this device, the SRAM data is not guaranteed to be preserved during Reset. 2 AVR180,
AVR180 Prevents Non-volatile Non-volatile memories like EPROM, EEPROM, and Flash are designed to keep their Memory Corruption contents even when power is completely removed from the system. By the use of aDetector to keep the MCU in Reset, all activity on the control lines cease. The memory contents are such prevented from unintentional writes from the CPU for the duration of the Reset. Without a Detector, random CPU activity such as described in the introduction may ini- tialize an unintended write to the non-volatile memory. This may cause random corruption of the memory contents. Notes: 1. As the AVR CPU is not capable of writing to its own program memory, the internal Flash Program memory contents are never affected by a power failure situation. 2. For any write to non-volatile memory, a minimum voltage is required to successfully write the new values into the memory. If supplied voltage at any time during the write cycle drops below the minimum voltage, the write will fail, corrupting the location written to. 3. In some AVR devices, when the reset activates during a write to the internal EEPROM, the EEPROM Address Register will be set to zero (0x000). The result may be seen as corruption of both the location being written, and of location zero (0x000).
Flash Program Memory The Internal Flash Program Memory contents are never affected by a power failure situ-ation. The AVR CPU is incapable of writing to its own program memory.
Volatile Memory Even when external low voltage detectors halts the CPU, volatile memory (like Regis-ters and RAM) will eventually loose their contents if the supply voltage drops below the minimum voltage required for each memory cell to preserve its current value. When the CPU is halted, the minimum voltage where the AVR internal RAM is guaranteed to pre- serve the contents is typically 2.0 volts. Factory tests on actual silicon have shown that AVR devices may preserve the RAM contents even down to 0.5 - 1.0 volts.
Implementation A variety of Integrated Circuit (IC) solutions are available from a range of manufacturers.These offer a high accuracy solution at a low price, typically guaranteeing the threshold voltage to be within ± 1%. Although the elementary three pin fixed voltage detector is available, there is also a whole range of devices offering additional features like Reset Pulse stretching, Power-on Reset Time-out, Watchdogs, Power regulation, dual supply switching for UPS operation and more. Included in this application note is a guide to the world of integrated circuit solutions. As an alternative, this application note also presents two discrete Low-Power Supply Voltage RESET Detectors. • Alternative 1: Minimum Power Consumption. Well-suited for battery-powered applications where power consumption is the most critical parameter. • Alternative 2: Minimum Cost. This is a minimum component cost solution for applications where cost is a key parameter and power consumption is not critical. • Alternative 3: High accuracy. High-quality semiconductor ICs are used to build an accurate Brown-out Detector with low-power consumption.
Design Hint: Supply Use low impedance capacitors (low ESR and ESL) on the VCC and multi-layer PCB with Voltage Filtering power planes to improve transient rejection from the power supply.,
Alternative 1: Low-power Consumption
Characteristics • Very Low-power Consumption, (Typ 0.5µA@3V, 1µA@5V)• Low-cost • Large Hysteresis, Typ. 0.3 Volts • Fast Output Transitions • Accuracy ± 5-10% • High Component Count • Long Response Time on VCC Figure 1. Low-power Consumption Brown-out Detector
VCC AVRR4 R5 ISP<50K VCC T3 100 - 500K R1 R3 OPTIONAL RESET C3 T2 RESET GND T1 SWITCH R2 C1 C2 Figure 2. These Oscilloscope Plots Show How the Voltage on RESET Varies with VCC 4 AVR180,
AVR180 Introduction The circuit in Figure 1 benefits from low-power consumption, which makes it suitable forbattery operated applications. Standard discrete components give a low cost design. The voltage transition on the RESET pin is very steep. Combined with the large hystere- sis, the accuracy is high. On the other hand, the response time is slow, which makes it unsuitable for rapidly varying supply voltages.
Theory of Operation This Detector has two stages, the Detector and the Amplifier. In the Detector stage, thethreshold voltage is set by the resistors R1 and R2 in relation to the critical voltage of transistor T1. Under normal operation, this transistor is conducting, When the supply voltage drops below the threshold voltage, the transistor shuts off. The output from this Detector is lead to the input of the ultra low power Amplifier stage. Under normal operation, the low voltage of the base of transistor T2 causes it to remain shut, allowing resistor R5 to pull the RESET input high. The Amplifier stage also con- tains a hysteresis feedback loop through transistor T3, shorting resistor R3 in the amplifier when the RESET output is kept low.
Choosing ComponentsT1, T2, and T3 The production spread of current gain β (or hFE) in transistors T1 affects the threshold voltage VT (typically ± 0.2 volts). Most small signal transistors can be used, but low pro- duction spread transistors are recommended. Care should be taken if transistor T1 is changed from one type to another. The emitter- base threshold voltage of T1 affects the constant (0.4) in the equation for threshold volt- age (below). As a consequence, a change of transistor could cause a change in the threshold voltage of the detector, which requires the voltage divider R1 + R2 to be recalculated. R1 and R2 R1 and R2 forms a voltage divider that defines the threshold voltage VT. As the thresh- old voltage depends on these resistors, it is recommended to choose resistors with 1% tolerance or better. Also see “Noise Sensitivity” below. R1 is usually chosen equal to 10 MΩ to ensure the lowest power consumption possible. R2 is then found by the equation below. The constant (0.4) in the equation may vary slightly with variations in transistor T1: VT = (R1 + R2) ⋅ -.-4- , or R2 = -0-.-4-⋅-R-1- R2 VT – 0.4 R3 R3 is a non-critical pull-up resistor which has very little influence on the threshold volt- age. It should be selected as large as possible to minimize power consumption. A resistance of R3 greater than 10 MΩ is not recommended, see “Noise Sensitivity” below. R4 Resistor R4 defines the hysteresis of the threshold voltage (VT). By choosing R4 to 3.3 MΩ, the resulting hysteresis will be approximately 0.3 volts. A smaller R4 will give a larger hysteresis, a larger R4 gives smaller hysteresis. A larger R4 will also result in a less sharp transition in the output slope. Large deviations from the recommended value will eventually alter the constant 0.4 in the threshold voltage equation above. As the hys- teresis is only slightly changed with variation in R4 resistance, the accuracy is not critical., R5 Resistor R5 pulls the RESET pin high in Normal Operating mode. A value less than 50 kΩ is recommended to tie RESET sufficiently hard to VCC. As no current passes through this resistor in normal operating mode, its value and accuracy is otherwise of lit- tle importance. When RESET is pulled low, this resistor will start conducting a relatively large current. C1 and C2 Capacitors C1 and C2 short RF noise picked up in the circuitry and amplified by the transistors. Both capacitors can be omitted, but a value greater than 1 nF is recom- mended. For maximum noise immunity, 100 nF (LF) or capacitors with lower ESR (HF) should be selected when possible. Also see “Response Time” below. The accuracy is not critical, but to ensure proper RF decoupling, the capacitors should have Z5U dielec- tric or better. C3 Capacitor C3 decouples the power lines. It can be omitted if there is RF decoupling of the power lines somewhere nearby on the circuit board, otherwise 1 nF is recom- mended. For maximum noise immunity, 100 nF (LF) or low ESR (HF) should be selected.
Reset Switch/In-System If a push button reset and/or ISP capabilities are required, they are simply connected in Programming parallel as shown in Figure 1. As the switch/programmer will pull RESET low, powerconsumption in R5 will be relatively high for the duration of the event. Also see “Power Consumption” below.
Response Time Choosing large values for capacitors C1 and C2 will slow down the circuit’s responsetime. This is not a problem with battery driven applications where the supply voltage decreases slowly over time. Observe that the response time also applies to the time immediately following Power-on. This might affect operation when a flat battery is loaded. When power can drop more rapidly, the longer response time should be taken into consideration.
Noise Sensitivity Choosing values of R1 and R3 greater than 10 MΩ is not recommended, as it makes thecircuitry sensitive to thermal noise generated in the resistor. When noise is not critical, the values of R1 and R3 can be raised to 20 MΩ. Choosing larger values will result in the resistors not conducting sufficient current, giving in a non-functional Detector. If more noise immunity is required, these resistors can be chosen smaller, at the expense of increased power consumption. Capacitors C1, C2 and C3 are decoupling capacitors to minimize noise sensitivity to both RF and 50/60 Hz fields. They can all be omitted, but the noise immunity depend strongly on the values selected.
Threshold Accuracy As the threshold voltage is defined mainly by R1 and R2, inaccuracies in these resistorsdirectly influence the threshold voltage accuracy. It is recommended to choose these with ± 1% tolerance. 6 AVR180,
AVR180 Power Consumption The current consumption in normal operating mode (sufficiently high VCC) is found by: VI ≈ -C-C- || = V CC - 1- + -1- (R1 + R2 ) (R3 + R4) R1 + R2 R3 + R4 When reset switch or programmer force RESET to GND, the current increases to:
VI ≈ -|-|- C-C-|-|-(R1 + R2) (R3 + R4 ) R5 || R
RESETWhen voltage drops to the level where the detector activates, transistor T1 closes, T2 opens and the current is:
VI ≈ -|-
C|- C-|-|-(R1 + R2) R5 R
RESETAs resistor R5 is usually chosen much smaller than the other resistors R1-R4, the last two expressions both simplify to:
VI ≈ -|-|- C-C- R5 R
RESETTable 1. Example Values Example Values Component 3.0V 4.5V Recommended Tolerance T1, T2 BC548/BC848/2N3904 ICE ≥ 2.5 mA, VCE ≥ 8 V, β/hFE ≥ 100 T3 BC558/BC858/2N3906 ICE ≥ 2.5 mA, VCE ≥ 8 V, β/hFE ≥ 100 R1 10 MΩ ≤ 1% R2 1.54 MΩ 976 kΩ ≤ 1% R3 10 MΩ ≤ 20% R4 3.3 MΩ ≤ 20% R5 47 kΩ ≤ 20% C1, C2, C3 100 nF ≤ 20%, Z5U dielectric or better,
Alternative 2: Low-cost
Characteristics • Low-component Count• Very Low-cost • Small Footprint • Short Response Time • Small Hysteresis • Output Drops Slowly with VCC • Low Accuracy (± 4-8%) • High Current Consumption • Sensitive to Component Variations Figure 3. Low-cost Brown-out Detector
VCC AVRR2 VCC T1 100 - 50K
GNDFigure 4. Low-cost Brown-out Detector with Manual Reset Button
VCC AVRR2 ISP VCC T1 100 - 50K R4
OPTIONALR1 RESETR3 RESET GND
AVR180Figure 5. These Oscilloscope Plots Show how the Voltage on RESET Varies with VCC
Introduction Figure 3 is showing a circuit that features low cost and small physical size. However, itshigh current consumption might make it unsuited for battery operated applications. As the voltage transition on the RESET pin is fairly slow when VCC drops, the circuit is sen- sitive to inaccuracies in component values. Due to inaccuracies in resistors R1 and R2, transistor T1 and AVR MCU RESET threshold value, the threshold value VT should be chosen minimum 15% below nominal VCC.
Theory of Operation During normal operation, the transistor T1 is open, keeping RESET at VCC. When thesupply voltage VCC drops below the threshold voltage (VT), the transistor T1 closes. This allows resistor R3 to pull RESET low (active). The closing of the transistor T1 occurs when the voltage from emitter to base drops below a certain value, usually 0.7 volts in small signal silicon transistors. R1 and R2 is a voltage divider that controls the emitter-base voltage. The threshold volt- age, VT, is defined by: ≈ R1 + R2 R1
VVT 0.7 ⋅ -, or - ≈ - T- – 1 R2 R2 0.7,
Choosing ComponentsT1 Almost any small signal PNP transistor can be used. One with high gain (β/hFE) is rec- ommended as it gives faster transitions in the output voltage with variations in VCC around the threshold voltage. Faster transitions make the circuit more immune to com- ponent variation, reducing the need to calibrate the Detector. Also see “Threshold Accuracy” on page 6. Calibration is also required if the threshold voltage for the transistor varies. This voltage is the constant 0.7 in the equation above. The voltage is stable for the same type of tran- sistor, but take care when selecting a transistor. A change in this parameter will seriously affect the threshold voltage of the Detector. R1 and R2 As the formula states, the threshold voltage VT is dependent upon R1 and R2. Resistor R1 should be about 200 kΩ or lower. This ensures that the current out of the transistor T1’s base will not influence the voltage divider R1-R2. (This is for an amplification (β/hFE) value of at least 100.) R3 The AVR’s RESET pin has an internal pull-up resistor with a nominal value of 100 - 500 kΩ. When transistor T1 is off, the internal pull-up and R3 form a voltage divider. The resulting RESET voltage has to be sufficiently low to assure that the MCU RESET line is held active. The recommended value for resistor R3 is 50 kΩ or lower, which ensures that the voltage at RESET is always less than 1/3 VCC.
Reset Switch/In-System If push button reset and/or ISP capabilities are required, a series resistor R4 must be Programming connected as shown in Figure 4. This resistor allows the reset switch/programmer tooverride the transistor T1 and pull the RESET pin low. To ensure proper low voltage detector operation, the series resistance in R3 + R4 should not exceed the recom- mended 50 kΩ.
Threshold Accuracy As the threshold voltage is defined mainly by R1 and R2, inaccuracies in these resistorsdirectly influence the threshold voltage. It is recommended to use resistors with ± 1% tolerance. Due to the slow transitions on the output of the detector, variations in RESET threshold in the AVR MCU will lead to inaccuracies in threshold voltage. This inaccuracy is typi- cally ± 0.15 volts, which equals ± 3% in a 5V system. (± 5% at 3.3V). This inaccuracy is lowered by choosing a transistor T1 with higher gain (β/hFE) which increases the transi- tion speed. 10 AVR180,
AVR180 Power Consumption The current through the detector in normal operating mode (sufficiently high VCC) isfound by:
VI ≈ -C-C-|-|-= V -1- + -1- (R1 + R2) R3 CCR1 + R2 R3 When switch or programmer force RESET to GND, the current increases to:
VI ≈ -|-|- C-C|-|-|-|-(R1 + R2 ) R3 R4 R
RESETWhen voltage drops to the level where the transistor T1 closes, the current drops to:
VI ≈ -|-|- C-C- (R1 + R2 ) (R3 + R4 + R )
RESETTable 2. Example Values Example Values Component VT = 3.0V VT = 4.5V Recommended Tolerance T1 BC558/BC858/2N3906 ICE ≥ 2.5 mA, VCE ≥ 8 V, β/hFE ≥ 100 R1 180 kΩ ≤ 1% R2 56 kΩ 33 kΩ ≤ 1% R3 ≤ 47 kΩ ≤ 20% R4 ≤ 4.7 k ≤ 20%,
Alternative 3: Integrated Circuit Solutions Characteristics • Easy to Mount• Very Accurate Threshold Voltage • Low Power Consumption • Small Footprint • Low Component Count • Wide Variety in Additional Functionality
Introduction A selection of integrated circuits is available from various semiconductor suppliers. Theyvary from simple 3-pin fixed voltage detectors to advanced circuitry containing Watch- dog Timers and Power-on Reset (POR) Timeouts. Because all AVR MCUs have built-in Watchdog and POR circuitry, these functions do not require handling by the external IC. The threshold accuracy is better than ± 1% for most circuits. Current consumption is in the µA range. Make sure to choose a device with an active low output. A wide variety of package types are available, ranging from miniature 3-pin SOT-23 to large packages with high pin count. Figure 6. Detector with Push-pull Output
VCC ISPR1 1 - 4K DETECTOR RESET LOGIC OPTIONAL
RESET SWITCHFigure 7. Detector with Open-drain Output
VCC ISP RESET DETECTORLOGIC OPTIONAL
RESET SWITCHFigure 8. Alternative Location of Manual Reset Switch
AVR180 Output Driver The IC Reset output can be push-pull or open drain (open collector), either CMOS orTTL output levels. Open drain solutions allow easy connection of a manual reset button and/or In-System Programmers. This feature can also be implemented with push-pull outputs, with the addition of a resistor in series with the output. The ISP and/or manual button is connected between the resistor and the AVR RESET input (see Figure 6 and Figure 7). Figure 9. Reset Pulse Stretching
VCC VTRESET WITHOUT tBROWN-OUT PULSE STRETCHING RESET WITH tBROWN-OUT tRST PULSE STRETCHING Reset Pulse Stretching An additional feature in some of these circuits is stretching of the reset pulse. The Reset is held active for a defined amount of time after the condition (Power-on Reset, Brown- out Reset etc.) that caused the reset has returned to normal (see Figure 9). Some of these devices also provide this feature for the Manual Reset. The device senses the output level, detecting the closing and opening of a reset button. When the button is released, the device keeps the reset line active for an additional amount of time. WARNING! This feature will interfere with the operation of an In-System Programmer, which toggles the RESET line actively.
Power Regulator Several integrated power regulators includes the Low-voltage Detector, combining bothfunctionalities in one device. This reduces part count, and often adds the functionality at no extra cost.
Battery Backup Some systems contain a battery to supply power when the main power drops. The Solutions power regulator in such systems often provides a status signal to the MCU telling whichsource currently supplies power to the circuit. Connecting this signal to RESET will shut the AVR down when battery power is used, preserving RAM contents but halting execu- tion. Alternatively, connecting this signal to an input pin, the AVR can detect the event and execute a safe power down sequence, switching off power hungry peripheral equip- ment (motor, display etc.) before entering Power-down mode. (The power consumption in RESET is the same as in Normal Active Running mode, whereas the consumption in power down mode is in the µA range.) When main power supply voltage returns to an acceptable level, the AVR should detect the event, wake up and resume execution where it left off., Figure 10. Adding Hysteresis to Threshold Voltage
ISPR1 DETECTOR 1 - 4K W RESET LOGIC OPTIONAL
RESET SWITCH Hysteresis Hysteresis in the Low-voltage Detector might be implemented in the integrated circuit, orcan be added with external circuitry (Figure 10). This prevents the detector from oscillat- ing when used in battery applications. Figure 11. Integrated Reset Circuit with Preset Threshold Voltage
VCC VCCRESET RESET GND OPTIONAL RESET GND
SWITCHFigure 12. Integrated Reset Circuit with Adjustable Threshold Voltage
VCC VT AVR VCCR1 V ISPCC IN RESET RESET R2 GND OPTIONAL RESET GND
SWITCH Fixed/Adjustable Some circuits offer the threshold voltage VT to be tuned by external components, while Threshold Voltage others have a preset threshold voltage reference. The use of a fixed threshold voltageIC is shown in Figure 11. The typical connection for externally tuned threshold voltage is shown in Figure 12. This device offers an internal voltage reference and a comparator. If the voltage at the input pin is higher than the reference voltage, the output will be activated. The threshold volt- age is easily defined by a voltage divider, R1 and R2. 14 AVR180,
AVR180Table 3. Example Devices Device Features ISP Support Cost Level(4) MAX809(1) Fixed Threshold Voltage, Fixed Pulse Stretching Yes A MAX811(1) Fixed Threshold Voltage, Fixed Pulse Stretching, Low Power, Manual Reset Input Yes A MAX821(1) Fixed Threshold Voltage, Adjustable Pulse Stretching, Low Power Yes DS1811(2) Fixed Threshold Voltage, Fixed Pulse Stretching Yes DS1813/18(2) Fixed Threshold Voltage, Fixed Pulse Stretching, Feedback Monitor No V6301(3) Fixed Threshold Voltage, Fixed Pulse Stretching, Low Power, Low Cost Yes C V6340(3) Fixed Threshold Voltage, No Pulse Stretching, Low Cost Yes C Notes: 1. Offered by Maxim Integrated Product, Inc. 2. Offered by Dallas Semiconductors. 3. Offered by EM Microelectronic-Marin SA. 4. A = expensive. B = moderate. C = inexpensive.,
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Microcontrollers for Fluorescent and High Intensity Discharge Lamp Ballasts SMARTER, MORE FLEXIBLE LIGHTING SOLUTIONS
LIGHTINGMICROCONTROLLERSMicrocontrollers for Fluorescent and High Intensity Discharge Lamp Ballasts SMARTER, MORE FLEXIBLE LIGHTING SOLUTIONS Developed together with the industry leading lamp ballast manufac- turers, Atmel® microcontrollers are optimized for Linear and Dimmable Fluorescent tubes, as
AVR121: Enhancing ADC resolution by oversampling Features • Increasing the resolution by oversampling • Averaging and decimation • Noise reduction by averaging samples 1 Introduction Atmel’s AVR controller offers an Analog to Digital Converter with 10-bit resolution. In most cases 10-bit resolution
IC Block Diagrams 8-1 Main 8-1-1. FAN8082D 8-1 Samsung Electronics 8-1-2. LC87F66C8A Samsung Electronics 8-2 8-3 Samsung Electronics Samsung Electronics 8-4 8-5 Samsung Electronics 8-1-3. M62446AFP Samsung Electronics 8-6 8-7 Samsung Electronics 8-1-4. M66010FP 8-1-5. SI-8050SE 8-1-6. SI-8090JFE S
AVR053: Calibration of the internal RC oscillator Features • Calibration using STK500, AVRISP, JTAGICE or JTAGICE mkII • Calibration using 3rd party programmers • Adjustable RC frequency with +/-1% accuracy • Tune RC oscillator at any operating voltage and temperature • Tune RC oscillator to any fre
8-bit Microcontroller Application Note Rev. 2541D–AVR–04/05 AVR230: DES Bootloader Features • Fits All AVR Microcontrollers with Bootloader Capabilities • Enables Secure Transfer of Compiled Software or Sensitive Data to Any AVR with Bootloader Capabilities • Includes Easy To Use, Configurable Examp
AVR106: C functions for reading and writing to Flash memory Features • C functions for accessing Flash memory - Byte read - Page read - Byte write - Page write • Optional recovery on power failure • Functions can be used with any device having Self programming Program memory • Example project for us
8-bit Microcontroller Application Note Rev. 1631C–AVR–06/02 AVR201: Using the AVR® Hardware Multiplier Features • 8- and 16-bit Implementations • Signed and Unsigned Routines • Fractional Signed and Unsigned Multiply • Executable Example Programs Introduction The megaAVR is a series of new devices i
Printed Circuit Board Diagram 5-1 MAIN 5-1 Samsung Electronics 5-2 FRONT Samsung Electronics 5-2 5-3 DSP 5-3 Samsung Electronics 5-4 JACK * RCA JACK * SCART JACK Samsung Electronics 5-4 5-5 DVD PACK * TOP VIEW * BOTTOM VIEW 5-5 Samsung Electronics
8-bit Microcontroller Application Note AVR105: Power Efficient High Endurance Parameter Storage in Flash Memory
8-bit Microcontroller Application Note Rev. 2546A–AVR–09/03 AVR105: Power Efficient High Endurance Parameter Storage in Flash Memory Features • Fast Storage of Parameters • High Endurance Flash Storage – 350K Write Cycles • Power Efficient Parameter Storage • Arbitrary Size of Parameters • Semi-redu
8-bit RISC Microcontoller Application Note Rev. 2505A–AVR–02/02 AVR130: Setup and Use the AVR® Timers Features • Description of Timer/Counter Events • Timer/Counter Event Notification • Clock Options • Example Code for Timer0 – Overflow Interrupt • Example Code for Timer1 – Input Capture Interrupt •
8-bit RISC Microcontroller Application Note Rev. 2585A–AVR–11/04 AVR151: Setup And Use of The SPI Features • SPI Pin Functionality • Multi Slave Systems • SPI Timing • SPI Transmission Conflicts • Emulating the SPI • Code examples for Polled operation • Code examples for Interrupt Controlled operati
AVR241: Direct driving of LCD display using general IO Features • Software driver for displays with one common line • Suitable for parts without on-chip hardware for LCD driving • Control up to 15 segments using 16 IO lines • Fully interrupt driven operation Introduction As a low power alternative t
8-bit Microcontroller Application Note Rev. 0938B–AVR–01/03 AVR204: BCD Arithmetics Features • Conversion 16 Bits ↔ 5 Digits, 8 Bits ↔ 2 Digits • 2-digit Addition and Subtraction • Superb Speed and Code Density • Runable Example Program Introduction This application note lists routines for BCD arith
8-bit Microcontroller Application Note Rev. 2530B–AVR–01/04 AVR065: LCD Driver for the STK502 and AVR Butterfly Features • Software Driver for Alphanumeric Characters • Liquid Crystal Display (LCD) Contrast Control • Interrupt Controlled Updating • Conversion of ASCII to LCD Segment Control Codes (S
8-bit Instruction Set Rev. 0856D–AVR–08/02 Instruction Set Nomenclature Status Register (SREG) SREG: Status Register C: Carry Flag Z: Zero Flag N: Negative Flag V: Two’s complement overflow indicator S: N ⊕ V, For signed tests H: Half Carry Flag T: Transfer bit used by BLD and BST instructions I: Gl
8-bit Microcontroller Application Note Rev. 0933B–AVR–05/02 AVR102: Block Copy Routines Features • Program Memory (Flash) to SRAM Copy Routine • SRAM to SRAM Copy Routine • Extremely Code Efficient Routines Flash → SRAM: 6 Words, SRAM → SRAM: 5 Words • Runable Test/Example Program Introduction This
Novice’s Guide to AVR Development intended for "Bare Bone" AVR basics.Download these files to a temporary folder on your computer. ( e.g. C:\Temp ): people with no AVR STUDIO 4 This file contains the AVR Studio 4 Program. This The AVR microcontrollers are divided into three groups:
Novice’s Guide to AVR Development Preparing your PC for AVR Development Basic AVR Knowledge An Introduction Let's make an easy start, and download the files that we will need later on. The AVR Microcontroller family is a modern architecture, with all the bells andFirst you should download the files
AVR079: STK600 Communication Protocol Features 8-bit • Supported Commands and Command options • Command and Answer package formats Microcontrollers 1 Introduction Application Note This document describes the STK®600 protocol. The firmware is distributed with AVR Studio® 4.14 or later. The definition