Single channel ADC reading in Embedded C - Step-by-Step Execution

Concept Flow - Single channel ADC reading

Start ADC

↓

Wait for ADC conversion complete?

No→Wait

Yes↓

Read ADC value

↓

Use ADC value

↓

End or Repeat

This flow shows starting the ADC, waiting for conversion, reading the value, and then using it.

Execution Sample

Embedded C

ADC_Start();
while(!ADC_ConversionComplete());
int value = ADC_Read();
// Use value

This code starts ADC, waits until conversion is done, then reads the ADC value.

Execution Table

Step	Action	ADC Status	Conversion Complete?	ADC Value	Next Step
1	Call ADC_Start()	Started	No	N/A	Wait for conversion
2	Check ADC_ConversionComplete()	Started	No	N/A	Keep waiting
3	Check ADC_ConversionComplete()	Started	Yes	N/A	Read ADC value
4	Call ADC_Read()	Started	Yes	523	Use ADC value
5	Use ADC value	Started	Yes	523	End or Repeat

💡 ADC conversion complete is true, ADC value read successfully

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
ADC Status	Idle	Started	Started	Started	Started	Started
Conversion Complete	False	False	False	True	True	True
ADC Value	N/A	N/A	N/A	N/A	523	523

Key Moments - 2 Insights

Why do we need to wait for ADC_ConversionComplete() before reading the value?

Because the ADC value is only valid after conversion finishes, as shown in step 3 of the execution_table where conversion becomes true before reading.

What happens if we read ADC value before conversion is complete?

The value would be invalid or old, since conversion_complete is false in steps 1 and 2, so reading then would give wrong data.

Visual Quiz - 3 Questions

Look at the execution_table, what is the ADC value at step 4?

A 523

B N/A

C 0

D Conversion not complete

💡 Hint

Check the 'ADC Value' column at step 4 in execution_table

At which step does the ADC conversion complete become true?

A Step 1

B Step 3

C Step 2

D Step 5

💡 Hint

Look at the 'Conversion Complete?' column in execution_table

If ADC_ConversionComplete() never returns true, what happens in the execution flow?

A The program reads ADC value immediately

B The ADC value is set to zero automatically

C The program waits forever at the conversion check

D The ADC stops working

💡 Hint

Refer to the loop waiting for conversion in concept_flow and execution_table steps 1-2

Concept Snapshot

Single channel ADC reading:
1. Start ADC conversion
2. Wait until conversion complete flag is true
3. Read ADC value
4. Use the value for processing
Always wait for conversion to finish before reading.

Full Transcript

This example shows how to read a single channel ADC in embedded C. First, the ADC is started. Then the program waits in a loop checking if the conversion is complete. Once complete, the ADC value is read and can be used. The execution table traces each step, showing the ADC status, conversion flag, and value. Key points are to wait for conversion complete before reading, or else the value is invalid. The quiz questions help check understanding of when the ADC value is valid and what happens if conversion never completes.