add first peripheral set

[shakti-peripherals.git] / src / lib / ClockDiv.bsv

diff --git a/src/lib/ClockDiv.bsv b/src/lib/ClockDiv.bsv
new file mode 100644 (file)
index 0000000..b84894d
--- /dev/null
+++ b/src/lib/ClockDiv.bsv
@@ -0,0 +1,44 @@
+package ClockDiv;
+  /*=== Project imports ==*/
+  import Clocks::*;
+  /*======================*/
+  // =========================== Clock divider module ================ //
+  interface Ifc_ClockDiv#(numeric type width);
+    interface Clock slowclock;
+    method Action divisor(Bit#(width) in);
+  endinterface
+
+  module mkClockDiv(Ifc_ClockDiv#(width));
+    let defclock <- exposeCurrentClock;
+    Reg#(Bit#(1)) clk <- mkReg(0);
+    Reg#(Bit#(width)) rg_divisor <- mkReg(0);
+    Reg#(Bit#(width)) rg_counter <- mkReg(0);
+    MakeClockIfc#(Bit#(1)) new_clock <- mkUngatedClock(0);
+    MuxClkIfc clock_selector <- mkUngatedClockMux(new_clock.new_clk,defclock);
+    Bool clockmux_sel = rg_divisor!=0;
+    rule increment_counter;
+      if(rg_divisor!=0 && rg_counter >= rg_divisor)begin
+        rg_counter <= 0;
+        clk <= ~ clk;
+      end
+      else
+        rg_counter <= rg_counter + 1;
+    endrule
+
+    rule generate_clock;
+      new_clock.setClockValue(clk);
+    endrule
+
+    rule select_clock;
+      clock_selector.select(clockmux_sel);
+    endrule
+
+    method Action divisor(Bit#(width) in);
+      rg_divisor <= in != 0 ? in - 1 : 0;
+    endmethod
+
+    interface slowclock=clock_selector.clock_out;
+  endmodule
+  // ============================================================== //
+  
+endpackage