418
Communications Instructions
Section 5-30
TXD(48) operates differently in host link mode and no-protocol mode, so
these modes are described separately.
Note
Refer to
1-6 Communications Functions
for more details on using the TXD(48)
instruction, setting communications protocol in the PC Setup, etc.
Host Link Mode
N must be BCD from #0000 to #0061 (i.e., up to 122 bytes of ASCII). The
value of the control word (C) determines the port from which data will be out-
put, as shown below.
The specified number of bytes will be read from S through S+(N/2)–1, con-
verted to ASCII, and transmitted through the specified port. The bytes of
source data shown below will be transmitted in this order: 12345678...
The following table lists the Transmission Enabled Flags for each port. The
corresponding Transmission Enabled Flag will be ON when the CQM1H is
capable of transmitting data through that port.
The following diagram shows the format for host link command (TXD) sent
from the CQM1H. The CQM1H automatically attaches the prefixes and suf-
fixes, such as the node number, header, and FCS.
No-protocol Mode
N must be BCD from #0000 to #00256. The value of the control word deter-
mines the port from which data will be output and the order in which data will
be written to memory.
Port
Transmission Enabled Flag
CPU Unit’s built-in RS-232C port
AR 0805
Peripheral port
AR 0813
Serial Communications Board
Port 1
IR 20105
Port 2
IR 20113
Not used. (Set to 0.)
Not used. (Set to 0.)
Serial port specifier (when bits 12 to 15 are 0.)
0: CPU Unit's built-in RS-232C port
1: Serial Communications Board port 1
2: Serial Communications Board port 2
Port 0: Port other than the peripheral port
1: Peripheral port
Digit number: 3 2 1 0
0 0
MSB LSB
S
1
2
S+1
3
4
S+2
5
6
S+3
7
8
@ X X X X X X ......... X X X
*
CR
Header
code
Data (122 ASCII characters max.)
FCS
Node
number
Terminator
