Question

While programming the ADC0808/0809 IC what steps are followed?

(a) select the analog channel, start the conversion, monitor the conversion, display the digital results

(b) select the analog channel, activate the ALE signal (L to H pulse), start the conversion, monitor the conversion, read the digital results

(c) select the analog channel, activate the ALE signal (H to L pulse), start the conversion, monitor the conversion, read the digital results

(d) select the channel, start the conversion, end the conversion

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I want to ask this question from ADC, DAC Interfacing in chapter 8051 Microcontroller of Microcontroller

Answer 1

The correct answer is (b) select the analog channel, activate the ALE signal (L to H pulse), start the conversion, monitor the conversion, read the digital results

To explain: While programming the ADC0808/0809 IC firstly we need to select the channel from the A, B, C pins. Then we need to activate the ALE signal, this is needed to latch the address. Then we start the conversion from the WR pin. After monitoring the INTR pin we get to know about the end of the conversion. Then we activate the OE enable to read out data out of the ADC chip.