MODULE RS232T (IN clk, rst: BIT;   (*NW 15.9.2014*)
  IN start, fsel: BIT;  (*request to send a byte / freq select*)
  IN data: BYTE; OUT rdy, TxD: BIT);
  REG (clk) run: BIT;
    tick: [12] BIT;
    bitcnt: [4] BIT;
    shreg: [9] BIT;
  VAR endtick, endbit: BIT;
    limit: [12] BIT;
BEGIN limit := fsel -> 217 : 1302;
  endtick := tick = limit;
  endbit := bitcnt = 9;
  rdy := ~run;
  TxD := shreg.0;

  run := (~rst | endtick & endbit) -> 0 : start -> 1 : run;
  tick := (run & ~endtick) -> tick + 1 : 0;
  bitcnt := (endtick & ~endbit) -> bitcnt + 1 :
    (endtick & endbit) -> 0'4 : bitcnt;
  shreg := ~rst -> 1 :
    start -> {data, 0'1} :
    endtick -> {1'1, shreg[8:1]} : shreg;
END RS232T.