113. Altering the RS423 format
     ~~~~~~~~~~~~~~~~~~~~~~~~~
If you are experimenting with the RS423 serial port, and need to alter the
data format, then you can do so with the command *FX156,X,227 . The value of
X can be looked up in the table below, where X is 4*n. The default value on
the Beeb is n=5, corresponding to *FX156,20,227 .

 DATA BITS PARITY STOP BITS n X
 --------- ------ --------- - --
     7      even      2     0  0
     7      odd       2     1  4
     7      even      1     2  8
     7      odd       1     3 12
     8      none      2     4 16
     8      none      1     5 20
     8      even      1     6 24
     8      odd       1     7 28

You can read the current value of n using the following function. If you want
to read the value of X rather than of n, then change the &400 in line 1020 to
&100. Note the comment in tip #111 about X% being LOCAL.

 1000 DEF FNstatus:LOCAL A%,X%,Y%
 1010 A%=156:Y%=255
 1020 =(USR(&FFF4) AND &1C00) DIV &400