Receive Commands; Special Control Commands; Start-Stop Printer Interface Commands - IBM 5280 Technical Newsletter

There are eight versions of the write control information
command; two for each of the four ports. Four of the
versions are used to gate the transmit/receive data to the
start-stop cable. The other four versions are used to cause
the data to wrap from the transmit driver to the receiver.
The functions available using the write control information
(both transmit and wrap) command are:
• I nternal reset of the start-stop printer adapter.
• Reset of start-stop printp.r adapter errors.
• Break request.
• Receive enable.
• Transmit enable
Write Data
The start-stop printer attachment MPU uses this command
to cause data and printer commands to be transmitted to
the printer. The data to be transmitted is placed in the 100
register. If a printer command is to be issued, the write data
command must be preceded by an interface break command
sequence.
There are eight versions of the write data command; two
for each of the four ports. Four of the versions are used to
gate data to the transmit pair of the start-stop cable. The
other four versions are used to cause a wrap from the
transmit driver to the receiver.
Receive Commands
Read Status
The start-stop printer attachment MPU issues this command
to the start-stop printer adapter to read the status in the
serdes. Wehn this command is placed into the EAR register,
the start-stop printer adapter gates the serdes status into the
100 register.
There are eight versions of the read status command; two for
each of the four ports. Four of the versions are used when
the data transmit/receive function is gated to the start-stop
cable. The other four versions are used when the data
transmit/receive function is wrapped from the driver to the
receiver.
Read Data
Page of SY31-0600-1
As updated April 15, 1981
By
TN
L
SN20-9588
The start-stop printer attachment MPU issues this command
(while receive enable is set) to access the printer response
data in the serdes. When this command is loaded into the
EAR register, the control logic causes the serdes data to be
loaded into the 100 register.
There are eight versions of the read data command; two for
each of the four ports. Four of the versions are used to gate
the receive data from the start-stop cable into the receiver.
The other four versions are used when the transmitted data
is wrapped from the driver to the receiver.
Special Control Commands
There are two special control commands: set twinaxial mode
and set start-stop mode. These commands are used to allow
the start-stop adapter and the twinaxial adapter to be acces-
sed by the same printer attachment MPU.
Start-Stop Printer Interface Commands
Diagnose (DIA) Hex 11
This command causes the start-stop printer to execute its
internal diagnostics. After the internal diagnostics run, the
start-stop printer returns an exception acknowledge response
(EXCACK) and waits for the start-stop printer attachment
MPU to request the status byte.
Sense (SEN) Hex 12
This command, when used with PRO command, requests a
two-byte sense response from the start-stop printer. The
first sense byte is sent in response to the SEN command.
The second sense byte is sent in response to the PRO com-
mand.
Restart (RST) Hex 13
This command causes the start-stop printer to resume
printing from its buffer following a device exception.
Receive Block Clear (RBC) Hex 08
This command causes the start-stop printer to clear the last
partial block from the print buffer. If the integrity of the
last block is questionable, the start-stop printer attachment
MPU transmits an RBC command and the start-stop printer
responds with RES command. Normal data transfer then
continues with the start-stop printer attachment re-transmit-
ing the interrupted data block.
Printer Attachment 274.5