In a multi-channel ADC setup with continuous conversions using DMA, you’ll need to determine which ADC channel triggered the DMA callback in order to perform different tasks for each channel. To achieve this, you can follow these steps:

1. Configure ADC Channels: Set up your ADC to scan through multiple channels in continuous mode. Configure the ADC and DMA peripherals according to your microcontroller’s specifications. Each channel should generate an interrupt after a conversion is completed.

2. Configure DMA: Set up the DMA controller to handle the ADC data transfers. Make sure to enable the circular buffer mode so that DMA continues fetching data indefinitely.

3. DMA Callback Function: This function will be called by the DMA controller whenever a DMA transfer is complete. Since you are performing continuous conversions, this callback will be triggered after each complete scan of all the ADC channels.

4. Channel Identification: To identify which channel has triggered the callback, you can use a few methods:

a. Use ADC’s Current Channel Register: Many microcontrollers have a register that stores the current active channel. In the DMA callback, you can read this register to determine the current channel. Then, you can use conditional statements to perform different tasks based on the active channel.

b. Use DMA Transfer Counter: DMA controllers often have a transfer counter that indicates how many transfers have been completed. Since you’re performing a scan of multiple channels, you can calculate the active channel based on the transfer count and the total number of channels.

5. Conditional Statements: Once you’ve identified the active channel, you can use conditional statements to execute specific tasks based on the channel. For example:

void DMA_ADC_Callback(void) {
// Identify the active channel using the methods described above
uint8_t activeChannel = …; // Determine the active channel here

// Perform tasks based on the active channel
if (activeChannel == CHANNEL_0) {
// Task for channel 0
} else if (activeChannel == CHANNEL_1) {
// Task for channel 1
} else if (activeChannel == CHANNEL_2) {
// Task for channel 2
}
// Add more conditions for other channels as needed
}
`

By utilizing the methods mentioned above, you can accurately identify the channel that triggered the DMA callback and execute the appropriate tasks for each channel. Make sure to consult your microcontroller’s documentation for specific register names and details regarding DMA and ADC configuration.

The problem you’re encountering with UART (Universal Asynchronous Receiver-Transmitter) on your Nucleo-F446RE board may be attributed to several potential reasons. Given that you’ve noted that UART1 functions as expected while UART2 does not, it’s likely that there are hardware or configuration-related issues influencing this disparity. To better assist you, could you provide a link to the relevant portion of your code for further examination? This could help identify the specific points of concern and provide more precise guidance for resolving the problem.

Designing a lithium polymer battery charger from scratch, without using any pre-made charging ICs, demands careful attention to safety and specific charging requirements.
Here’s a list of components you’ll need:

1. Voltage Regulator (LM317): This will regulate the charging voltage.
2. N-channel MOSFET (e.g., IRF540): It controls the charging current.
3. Resistor: Required to set the charging current limit.
4. Diode (e.g., 1N4007): To protect against reverse polarity.
5. Resistors and Capacitors: For voltage and current sensing during charging.
6. LED and Resistor: For indicating the charge status.
7. Potentiometer: To adjust the voltage regulation for your battery.

Let’s outline the circuit design:

1. Connect the positive terminal of the lithium polymer battery to the input of the LM317 voltage regulator.

2. The LM317’s output connects to the drain of the N-channel MOSFET.

3. Set the charging current limit by placing a resistor between the source of the MOSFET and the ground. To calculate the current limit (ILIM), use ILIM = 1.25V / R, where R is the resistor value in ohms.

4. Place a diode in series with the battery to prevent reverse current flow.

5. Use resistors and capacitors to monitor the battery’s voltage and current during the charging process.

6. Add an LED, along with a resistor, to indicate the charge status. For example, you can use a green LED while charging and a red one to show the battery is fully charged.

7. To regulate the charging voltage, include a potentiometer in the feedback path of the LM317. This allows you to set the desired voltage for your specific lithium polymer battery.

8. Connect a suitable power source (AC-DC adapter or DC power supply) to power the circuit and initiate the charging process.

Safety Precautions:

– Make sure the voltage and current limits are correctly set according to your lithium polymer battery’s specifications (e.g., 3.7V per cell and 350mA charging current for a 1C rate).

– Provide adequate heat sinking for the LM317 and MOSFET to dissipate any heat generated during charging.

– Carefully check the battery’s polarity and connections to avoid any reverse polarity issues.

– For added safety, consider incorporating features like temperature monitoring and overcurrent protection.

– During testing, regularly monitor the charging process and battery temperature to ensure the circuit operates within safe limits.