Added and simplified COM module.

Directly use pins, no complicated redirections.
Router modules will probably use real UARTs or MCUs programmed as UARTs.

avr/utils.asm

@@ -1,6 +1,47 @@
 
 
 
+; Utils_WaitNanoSecs  waittime_in_ns , cyles_already_used , waitcount_register 
+;
+;     cycles already used will be subtracted from the delay
+;     the waittime resolution is 1 cycle (delay from exact to +1 cycle)
+;     the maximum delay at 20MHz (50ns/clock) is 38350ns
+;     waitcount register must specify an immediate register
+; taken from https://www.mikrocontroller.net/articles/AVR_Assembler_Makros#Verz%C3%B6gerung_um_X_Nanosekunden
+;
+.set     Osc_Hz         = clock                    ; 1 MHz
+.set     cycle_time_ns  = (1000000000 / Osc_Hz)      ; clock duration
+.macro   Utils_WaitNanoSecs
+  .set cycles = ((@0 + cycle_time_ns - 1) / cycle_time_ns - @1)
+  .if (cycles > (255 * 3 + 2))
+    .error "MACRO Utils_WaitNanoSecs - too many cycles to burn"
+  .else
+    .if (cycles > 6)
+      .set  loop_cycles = (cycles / 3)      
+      ldi   @2,loop_cycles
+      dec   @2
+      brne  pc-1
+      .set  cycles = (cycles - (loop_cycles * 3))
+    .endif
+    .if (cycles > 0)
+      .if   (cycles & 4)
+        rjmp  pc+1
+        rjmp  pc+1
+      .endif
+      .if   (cycles & 2)
+        rjmp  pc+1
+      .endif
+      .if   (cycles & 1)
+        nop
+      .endif
+    .endif
+  .endif
+.endmacro
+
+
+
+
+
 ; ***************************************************************************
 ; Utils_FillSram
 ;
@@ -49,3 +90,7 @@ Utils_IncrementCounter32:
   st -x, r18
   ret
 
+
+
+
+