BIT  NAME     FUNCTION
  ---  ----     --------
   0   START    1 = start Timer A, 0 = stop Timer A.
                    This bit is automatically reset (= 0) when
                    underflow occurs during one-shot mode.
   1   PBON     1 = Timer A output on PB6, 0 = PB6 is normal operation.
   2   OUTMODE  1 = toggle, 0 = pulse.
   3   RUNMODE  1 = one-shot mode, 0 = continuous mode.
   4   LOAD     1 = force load (this is a strobe input, there is no
                    data storage;  bit 4 will always read back a zero
                    and writing a 0 has no effect.)
   5   INMODE   1 = Timer A counts positive CNT transitions,
                0 = Timer A counts 02 pulses.
   6   SPMODE   1 = Serial port=output (CNT is the source of the shift
                    clock)
                0 = Serial port=input  (external shift clock is
                    required)
   7   UNUSED