The document discusses interfacing an ADC IC0808/09 chip with a microcontroller. It describes how the ADC chip converts analog signals to digital signals using successive approximation. It explains the pinout, features and working of the ADC chip. It also discusses how to interface the ADC0809 chip with an 8051 microcontroller by selecting channels, initiating conversions and reading output data.
8051 timer counter
Introduction
TMOD Register
TCON Register
Modes of Operation
Counters
The microcontroller 8051 has two 16 bit Timer/ Counter registers namely Timer 0 (T0) and Timer 1 (T1) .
When used as a “Timer” the microcontroller is programmed to count the internal clock pulse.
When used as a “Counter” the microcontroller is programmed to count external pulses.
Maximum count rate is 1/24 of the oscillator frequency.
This presentation discusses the details of the I2C protocol and interfacing of EEPROM with 8051 based on I2C protocol. It also discusses the other applications of I2C protocol
8051 timer counter
Introduction
TMOD Register
TCON Register
Modes of Operation
Counters
The microcontroller 8051 has two 16 bit Timer/ Counter registers namely Timer 0 (T0) and Timer 1 (T1) .
When used as a “Timer” the microcontroller is programmed to count the internal clock pulse.
When used as a “Counter” the microcontroller is programmed to count external pulses.
Maximum count rate is 1/24 of the oscillator frequency.
This presentation discusses the details of the I2C protocol and interfacing of EEPROM with 8051 based on I2C protocol. It also discusses the other applications of I2C protocol
This presentation contains the basic information you need to know about operational amplifier.
I have tried to cover all the basic info. If anything is left out or you have any suggestions i will appreciate it.
This presentation discusses the support for interrupts in 8051. The interrupt types, interrupts versus polling etc are discussed. The register formats of IE, IP register are discussed. The concept of priority among the interrupts is discussed.
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems. It was invented by Philips and now it is used by almost all major IC manufacturers. Each I2C slave device needs an address – they must still be obtained from NXP (formerly Philips semiconductors).
This presentation contains the basic information you need to know about operational amplifier.
I have tried to cover all the basic info. If anything is left out or you have any suggestions i will appreciate it.
This presentation discusses the support for interrupts in 8051. The interrupt types, interrupts versus polling etc are discussed. The register formats of IE, IP register are discussed. The concept of priority among the interrupts is discussed.
I2C is a serial protocol for two-wire interface to connect low-speed devices like microcontrollers, EEPROMs, A/D and D/A converters, I/O interfaces and other similar peripherals in embedded systems. It was invented by Philips and now it is used by almost all major IC manufacturers. Each I2C slave device needs an address – they must still be obtained from NXP (formerly Philips semiconductors).
Analog-to-Digital Converter (ADC) is an integral part of high-speed signal processing applications. This paper discusses about 10-bit SAR based ADC that enables very low power consumption and sampling rate as high as 165 MSPS.
An analog-to-digital converter (ADC, A/D, or A to D) is a device that converts a continuous physical quantity (usually voltage) to a digital number that represents the quantity's amplitude.
The conversion involves quantization of the input, so it necessarily introduces a small amount of error. Instead of doing a single conversion, an ADC often performs the conversions ("samples" the input) periodically. The result is a sequence of digital values that have been converted from a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal.
Unit IV DA & AD Convertors and Phase Locked LoopDr.Raja R
Analog-to-digital, digital-to-analog, sample and hold circuits; voltage controlled oscillator, phase locked loop – operating principles, applications of PLL.
2. ADC INTERFACING USING
IC0808/09
WHAT IS ADC?
*An electronic integrated circuit which
transforms a signal from analog(continuous) to digital(discrete) form.
*Analog Signals are continuous in nature.
*Digital signals are finite in nature & only have two states ON & OFF i.e 0 & 1.
3. Why we need ADC?
*Microprocessors & Microcontrollers or any digital system can only
perform complex processing on digitized signals.
*When signals are in digital form they are less
susceptible to the deleterious effects of
additive noise.
*ADC Provides a link between the analog world of transducers and
the digital world of signal processing and data handling.
5. FEATURES OF 0808/0809
28 PIN DIP
Resolution-8 bits
8 INPUT & OUTPUT CHANNELS
Sample Rate (max) (SPS)-10K SPS
Successive approximation technique is used in this IC
High accuracy
High conversion speed[100ms at 640kHz]
8-channel multiplexer with latched control logic
Clock Frequency 10kHz to 1280kHz used clock frequency is 640 KHz
Latched Tri-state output
The IC internally consists of COMPAROTOR SAR, DAC etc.
8. INTERFACING OF ADC0809 WITH 8051
STEP1: FIRST THE CONTROLLER SELECTS A CHANNEL
ADDRESS THROUGH P0.0-P0.2 PORT LINES. THEN PORT 0.3
IS ASSERTED HIGH AND THEN A LOW SIGNAL TO LATCH
ADDRESS IN ADC.
STEP2:THE ADC CONVRSION IS INITIATED BY ASSERTING SOC
AS HIGH AND LOW THROUGH PORT 0.4 PIN.
STEP 3:THEN CONTROLLER KEEPS ON POLLING THE STATUS
OF EOC THROUGH P0.5 TO VERIFY WHETHER IT IS SET TO 1.
STEP4:WHEN THE CONTROLLER FINDS A VALID EOC i.e if
1,THEN IT WILL READ THE DIGITAL VALUE FROM THE OUTPUT
BUFFER BY SENDING A LOGIC HIGH ENABLE SIGNAL THROUGH
P0.6 PIN
10. SUCCESIVE APPROXIMATION METHOD:
TH IC consists of a successive approximation register (SAR), DAC and
comparator. The output of SAR is given to n-bit DAC. The equivalent analog
output voltage of DAC, VD is applied to the non-inverting input of the
comparator. The second input to the comparator is the unknown analog input
voltage VA. The output of the comparator is used to activate the successive
approximation logic of SAR.
When the start command is applied, the SAR sets the MSB to logic 1 and other
bits are made logic 0, so that the trial code becomes 1000
11. SUCCESSIVE APPROXIMATION WORKING:
PLEASE REFER THIS LINK FOR VIDEO ON SUCCESSIVE APPROXIATION
CALCULATION https://www.youtube.com/watch?v=jtb0XXnaYk8
13. Step size:
The step size is the voltage difference between one digital level (i.e. 0001)
and the next one (i.e. 0010 or 0000). For example if an ADC has a step size of
1 Volt an input of 1 volt will produce an output, in a 4 bit converter, of 0001.
0 volts is always considered 0000.
16. APPLICATIONS:
Scanner : When you scan a picture with a scanner , what scanner is doing is an analog
to digital conversion : it is taking the analog information provided by the picture(light)
and converting into digital form
Recording a voice : When you record your voice or use a VoIP solution on your
computer you r using analog to digital converter to Convert your voice , which is analog
into digital information.
