Getting started with Embedded C and Microcontroller

One best way to learn Embedded programming is to catch hold on one microcontroller and then explore all its features. Let's say you start with LPC1768 from NXP. Its a ARM cortex M3 based microcontroller.
for more details, check below link.
https://os.mbed.com/platforms/mbed-LPC1768/

After we freeze the microcontroller, we can begin exploring in the following order,
1. Clock Unit
    PLL
    Configuring clock unit for different frequency
    Check the clock pulse on CRO

2. GPIO
    Usage of GPIO registers
    Reading Switch input
    Driving a LED, Buzzer, Relay

3. WDT- Need
    How it works
    WDT configuration

4. Interrupt system
    Different kinds of interrupts
    Use of ISRs
    Interrupt Latency

5. ADC introduction
    Configuration of ADC
    Use of different ADC modes
    Reading a analog input at a pin

6. Timer Basics
    Application of timers
    Input capture
    Output compare
    Timer configuration for diff modes

7. PWM introduction
    PWM registers
    PWM generation
    Control intensity of light
    Control speed of motor

8. Serial communication introduction
    UART & its registers
    Programming a UART and establishing communication with serial terminal.

9. SPI protocol
    SPI registers
    Programming SPI

10. I2C Protocol
      I2C registers
      Programming I2C

11. RTC introduction
      RTC configuration
      Programming RTC for time keeping.