Start and stop conditions in Embedded C - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to generate a start condition on the I2C bus.

Embedded C

I2C->CR1 |= [1];  // Generate start condition

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AI2C_CR1_START

BI2C_CR1_ACK

CI2C_CR1_STOP

DI2C_CR1_PE

Attempts:

3 left

💡 Hint

Common Mistakes

Using the stop condition bit instead of the start condition bit.

Confusing the peripheral enable bit with the start condition bit.

The I2C_CR1_START bit is set to generate a start condition on the I2C bus.

2fill in blank

medium

Complete the code to generate a stop condition on the I2C bus.

Embedded C

I2C->CR1 |= [1];  // Generate stop condition

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AI2C_CR1_STOP

BI2C_CR1_ACK

CI2C_CR1_PE

DI2C_CR1_START

Attempts:

3 left

💡 Hint

Common Mistakes

Using the start condition bit instead of the stop condition bit.

Confusing the acknowledge bit with the stop condition bit.

The I2C_CR1_STOP bit is set to generate a stop condition on the I2C bus.

3fill in blank

hard

Fix the error in the code to correctly generate a start condition and wait for it to be set.

Embedded C

I2C->CR1 |= [1];
while(!(I2C->SR1 & I2C_SR1_SB));  // Wait for start bit set

Drag options to blanks, or click blank then click option'

AI2C_CR1_PE

BI2C_CR1_STOP

CI2C_CR1_ACK

DI2C_CR1_START

Attempts:

3 left

💡 Hint

Common Mistakes

Setting the stop bit instead of the start bit.

Not waiting for the start bit flag in the status register.

Setting I2C_CR1_START generates the start condition. The code waits until the start bit (SB) is set in the status register.

4fill in blank

hard

Fill both blanks to generate a stop condition and wait until the bus is free.

Embedded C

I2C->CR1 |= [1];
while(I2C->SR2 & [2]);  // Wait until bus busy flag clears

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AI2C_CR1_STOP

BI2C_SR2_BUSY

CI2C_CR1_START

DI2C_SR1_SB

Attempts:

3 left

💡 Hint

Common Mistakes

Waiting on the wrong status register flag.

Setting the start bit instead of the stop bit.

Set I2C_CR1_STOP to generate a stop condition. Then wait until the busy flag I2C_SR2_BUSY clears in the status register 2.

5fill in blank

hard

Fill all three blanks to generate a start condition, wait for it, and then generate a stop condition.

Embedded C

I2C->CR1 |= [1];  // Start condition
while(!(I2C->SR1 & [2]));  // Wait for start bit
I2C->CR1 |= [3];  // Stop condition

Drag options to blanks, or click blank then click option'

AI2C_CR1_START

BI2C_SR1_SB

CI2C_CR1_STOP

DI2C_CR1_ACK

Attempts:

3 left

💡 Hint

Common Mistakes

Not waiting for the start bit flag before generating the stop condition.

Using the acknowledge bit instead of start or stop bits.

First, set I2C_CR1_START to generate the start condition. Then wait for the start bit flag I2C_SR1_SB to be set. Finally, set I2C_CR1_STOP to generate the stop condition.