B&B Electronics 232BSS4 Manual page 11

Clear Receive Buffer – "X" + one control byte specifying which ports'
buffers to clear.
Documentation Number 232BSS41202 Manual
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A summary of the control characters for each combination of
ports is given in Table 2.2.
For instance, to broadcast to ports B & C, send:
{Char1}{Char2} {Char3} "S"{Decimal 6}
(B = 2, C = 4, 2 + 4 = 6)
VB Example:
BroadcastBC$ = CHR$(27) & CHR$(2) & "S" & CHR$(6)
The Clear Buffer command will tell the 232BSS4 which Slave
ports' receive buffers to purge. If the Master device is only
interested in the most recent data from the Slaves, this command
can be used to delete old data from one or more of the Slave port
buffers before it is sent to the Master.
The lowest four bits of the control byte tell the 232BSS4 which
ports' buffers to purge. Bit 0 represents port A, Bit 1 represents
port B, Bit 2 represents port C, and Bit 3 represents port D. In
decimal, this is represents a value of 1, 2, 4, and 8 respectively.
To clear more than one buffer with a single command, the
decimal equivalents of each port would be added together to give
the final byte.
A summary of the control characters for each combination of
ports is given in Table 2.2.
For instance, to clear the receive buffer on ports A & D, send:
{Char1}{Char2} {Char3} "S"{Decimal 9}
(A = 1, D = 8, 1 + 8 = 9)
VB Example:
ClearAD$ = CHR$(27) & CHR$(2) & "X" & CHR$(9)
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