pub type Exs1aW<'a, REG> = FieldWriterSafe<'a, REG, 2, Exs1a>;
Field EXS1A writer - Event Source Select for A1 (ERS1)
EXS1A
struct Exs1aW<'a, REG> { /* private fields */ }
Input ERU_1A0 is selected
Input ERU_1A1 is selected
Input ERU_1A2 is selected
Input ERU_1A3 is selected