Q2Microprocessor
Question
Q.2. Explain A/D converter interfaced with 8051 microcontroller.
Answer
An A/D converter (e.g., ADC0808/0809) is interfaced with the 8051 via its data bus (typically Port 0 or Port 1 for the 8-bit digital output) and control lines (START, ALE, EOC, OE) connected to 8051 I/O pins, which the program toggles to initiate conversion and read the digital result.
An Analog-to-Digital Converter (such as the ADC0808/0809, an 8-bit, 8-channel ADC) is interfaced with the 8051 microcontroller by connecting the ADC's 8-bit digital output bus to one of the 8051's I/O ports (commonly Port 1), and connecting the ADC's control signals — ALE (Address Latch Enable, to latch the analog channel select address), START (to initiate conversion), EOC (End of Conversion, an output signal the ADC uses to indicate conversion completion), and OE (Output Enable, to enable the ADC's tri-state output buffer onto the data bus) — to individual bit-addressable I/O pins of another 8051 port (commonly Port 3 pins). The 8051 program selects the desired analog input channel, pulses ALE and START to begin conversion, polls (or uses an interrupt from) the EOC signal to detect when conversion is complete, then asserts OE and reads the resulting 8-bit digital value from the data port.