3.2.2 Register Initialization Using Bit Positions

The same configuration, as presented above, can be done by using the bit position macros, as follows.

ADC0.CTRLA = (1 << ADC_ENABLE_bp)     /* Enable the ADC */
           | (1 << ADC_CONVMODE_bp)   /* Select Differential Conversion mode */
           | (1 << ADC_RESSEL0_bp)    /* 10-bit conversion */
           | (0 << ADC_RESSEL1_bp);

ADC0.CTRLA = (1 << ADC_ENABLE_bp)     /* Enable the ADC */
           | (1 << ADC_CONVMODE_bp)   /* Select Differential Conversion mode */
           | (1 << ADC_RESSEL0_bp);   /* 10-bit conversion */

Other position masks that can be used to configure bit fields are group position masks. They can be used as presented below. The desired configuration value must be shifted with the bit field position (group position).

ADC0.CTRLA = (1 << ADC_ENABLE_bp)      /* Enable the ADC */
           | (1 << ADC_CONVMODE_bp)    /* Select Differential Conversion mode */
           | (0x01 << ADC_RESSEL_gp);  /* 10-bit conversion */