If more than one DAC is being driven, Fig. The timing for this operation is shown, Fig. It is important to note that the analog outputs that will change after a simultaneous transfer are those from the DACs whose input register had been modified prior to the XFER command. The ILE pin is an active high chip select which can be decoded from the address bus as a qualifier for the normal CS signal generated during a write operation.
This can be used to provide a higher degree of decoding unique control signals for a particular DAC, and thereby create a more efficient addressing scheme. Pulling this line low latches the input register and prevents new data from being written to the DAC.
This can be particularly useful in multiprocessing systems to allow a processor other than the one controlling the DACs to take over control of the data bus and control lines. If this second system were to use the same addresses as those decoded for DAC control but for a different purpose the ILE function would prevent the DACs from being erroneously altered. In the case of the DAC Digital to Analog Converter, the output, I OUT1 , is a current directly proportional to the product of the applied referenced voltage and the digital input word.
More simply, DACs are devices that perform digital to analog conversion however, this conversion requires a reference value on the basis of which the conversion takes place. Sometimes there are internal references but all DACs do not have internal references thus in some cases power supply is used as a reference.
In general, it is known that a microprocessor generates only digital signal i. However, in some applications like in order to control analog devices, analog signals are needed. Due to this reason, DAC interfacing is necessary as using a DAC the digital output of the microprocessor can be converted into analog form. The input at the DAC unit is binary data which converts it into equivalent analog voltage or current. As we have discussed that a reference value is required therefore, for the operation to take place DAC needs either a reference analog voltage V ref or reference analog current I ref.
A word resolution is used to describe the smallest analog value that an n-bit binary code can represent. It is to be noted here that every analog output will be a multiple of the resolution.
This simply means that a digital input of 8-bit value can provide 2 8 i. As the name indicates the current and voltage output DACs are the ones that generate analog current and voltage signal respectively as its output.
The operation of voltage output DAC is such that internally the analog current signal is transformed into voltage equivalent. Other than these two types the third one is the multiplying type DAC that provides the output which is the product of applied input and the reference source. Though the difference is simple, even current output DAC and voltage output DAC can be considered as multiplying type DAC as all of them provide such an output which is the product of applied input with the reference value.
The output can be amplified optional using an op-amp. ADC with using ports. Let us see the circuit diagram of connecting , and the ADC converter. The PortA of chip is used as the input port. Explanation: The general algorithm for interfacing ADC contains ensuring the stability of analog input, issuing start of conversion pulse to ADC, reading end of conversion signal to mark the end of a conversion process, reading digital data output of ADC as equivalent digital output.
In more practical terms, an ADC converts an analog input, such as a microphone collecting sound, into a digital signal. An ADC performs this conversion by some form of quantization — mapping the continuous set of values to a smaller countable set of values, often by rounding.
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