Printer User Manual

Page 34
Upon timeout of the Power-Down-Timer, the printer starts flashing the red <Error> LED to warn
the operator, before turning power off.
Serial Baud Rate and Parity
Since IRD-ASK data transfer is serial, The proper Baud Rate and parity settings are required to
communicate with a Host computer.
Refer to MSP User's manual to set the desired baud rate and parity.
Software Interface Overview
This section details the software steps required for reliable serial IRD-ASK data transfer,
STEP 1 Select the Printer
The Host Selects the MSP printer by sending wake-up character to the printer.
To avoid the loss of data during printer select process, the Host pauses for 1.0
seconds before sending additional characters to the printer.
STEP 2 Initialize the Printer
The MSP User's Manual list the printer operating modes such as character set,
character width and height and graphics mode. These are all set to their default
state on printer power up.
To Initialize the Printer, the Host sends ASCII serial command string to enable
the desired operating mode.
STEP 3 Transmit the ASCII Data to printer
Since the IRD-ASK data transfer is in one direction, from Host to the printer, it is
the Host responsibility to be sure the printer's 2000 Byte buffer never
overflows.
The following simple timing technique can be implemented in the IRD-ASK
transmitter.
- Treat every line to be printed as a complete line, independent of the
number of characters on that line.
- Keep track of the number of lines sent.
- Before sending a line, check to see if print buffer is
full.
(50 lines for 24 column printers)
(28 lines for 40/42 column printer).
- If print buffer is full, Wait 2 seconds before sending the next line.