But there may a situation where we have to deal with external inputs such as analog signals. All most all the input signals from physical sensors are of analog signals. In such cases, we can interface the microcontroller with an external device such as an ADC to convert the analog signal to a digital signal. Because our microcontrollers can only understand 0 and 1. In this article, we look into the details of ADC interfacing with In the present time, there are lots of microcontrollers in the market which has inbuilt ADC with one or more channels, E.
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For interfacing these sensors to microcontrollers we require to convert the analog output of these sensors to digital so that the controller can read it. Why we are using ADC for Microcontroller? So we have to use external ADC. There are many ADCs available. ADC is a Successive approximation type with 8 channels i. I mean, In ADC we can give only one analog input. But in ADC we can give 8 analog inputs.
So if you want to interface more number of analog sensors, please select this ADC ADC is an 8 bit analog to digital converter with eight input analog channels, i.
The input which is to be converted to digital form can be selected by using three address lines. The step size is decided based on set reference value. Step size is the change in analog input to cause a unit change in the output of ADC. The default step size is The ADC needs some specific control signals for its operations like start conversion and bring data to output pins. When the conversion is complete the EOC pins goes low to indicate the end of conversion and data ready to be picked up.
Features Easy interface to all microprocessors Operates ratio metrically or with 5 V DC or analog span adjusted voltage reference No zero or full-scale adjust required 8-channel multiplexer with address logic 0V to 5V input range with single 5V power supply Outputs meet TTL voltage level specifications Standard hermetic or molded pin DIP package pin molded chip carrier package Pin Diagram.
8051 – ADC0808 Interfacing
Resolution: 8 Bits? Single Supply: 5 VDC? Low Power: 15 mW? The converter features a high impedance chopper stabilized comparator, a R voltage divider with analog switch tree and a successive approximation register. The 8-channel multiplexer can directly access any of 8-single-ended analog signals.
These devices are also designed to operate from common microprocessor control buses, with tri-state output latches driving the data bus. It eliminates the need for external zero and full-scale adjustments. Easy to interface to all microprocessors. It operates on single 5V power supply. Output meet TTL voltage level specifications. The address of the desired channel is sent to the multiplexer address inputs through port pins.