add blinky example

crates/fayalite/examples/blinky.rs

@@ -0,0 +1,50 @@
+use clap::Parser;
+use fayalite::{
+    clock::{Clock, ClockDomain},
+    hdl_module,
+    int::{DynUInt, DynUIntType, IntTypeTrait, UInt},
+    reset::{SyncReset, ToReset},
+};
+
+#[hdl_module]
+fn blinky(clock_frequency: u64) {
+    #[hdl]
+    let clk: Clock = m.input();
+    #[hdl]
+    let rst: SyncReset = m.input();
+    let cd = #[hdl]
+    ClockDomain {
+        clk,
+        rst: rst.to_reset(),
+    };
+    let max_value = clock_frequency / 2 - 1;
+    let int_ty = DynUIntType::range_inclusive(0..=max_value);
+    #[hdl]
+    let counter: DynUInt = m.reg_builder().clock_domain(cd).reset(int_ty.literal(0));
+    #[hdl]
+    let output_reg: UInt<1> = m.reg_builder().clock_domain(cd).reset_default();
+    #[hdl]
+    if counter == int_ty.literal(max_value) {
+        m.connect(counter, int_ty.literal(0));
+        m.connect(output_reg, !output_reg);
+    } else {
+        m.connect_any(counter, counter + 1_hdl_u1);
+    }
+    #[hdl]
+    let led: UInt<1> = m.output();
+    m.connect(led, output_reg);
+}
+
+#[derive(Parser)]
+struct Cli {
+    /// clock frequency in hertz
+    #[arg(long, default_value = "1000000", value_parser = clap::value_parser!(u64).range(2..))]
+    clock_frequency: u64,
+    #[command(subcommand)]
+    cli: fayalite::cli::Cli,
+}
+
+fn main() {
+    let cli = Cli::parse();
+    cli.cli.run(blinky(cli.clock_frequency))
+}