CognitiveTPG A798 - Manual (Page 65)

Chapter 4: Programming Commands 65 Revision C 12/09
A798-PG00001C
Print raster graphics
ASCII DC1 n1…..nl (576 dots) for 80 mm paper, or n80 (640 dots) for 82.5 mm paper
Hexadecimal 11 n1…..n72 (576 dots) for 80 mm paper, or n80 (640 dots) for 82.5 mm paper
Decimal 17 n1…..nl (576 dots) for 80 mm paper, or n80 (640 dots) for 82.5 mm paper
Value and range of n: n1 to n72/n80 corresponds to one dot row data for a thermal receipt printer.
Each bit defines whether or not a dot will be printed. This command is used for printing a graphic in real-time. Offsets,
page and any other modes or overlays, including watermark do not apply and are overridden by this command. A complete
rendering of the intended final image should have been done by the application before sending the dot rows.
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Status
Status command introduction
The A798 has three methods of providing status to the application. These methods are through batch status commands, real
time status commands and unsolicited status mode. An application may use one or more of these methods to understand
the current status of the printer. A brief description of each of these methods follows.
Batch status commands – These commands are sent to the printer and stored in the printer’s buffer. Once the printer has
processed all the previous commands these commands are processed and the proper status is returned to the application. In
the event a condition causes the printer to go BUSY, it stops processing commands from the printer buffer. If a batch status
command remained in the buffer during this busy condition, it would not be processed. In fact, no batch commands are
processed while the printer is in this state.
Real-time commands – These commands are sent to the printer buffer. Periodically, when the printer has time, it scans
the input buffer looking for these commands. When found by the printer, these commands are processed immediately.
This gives the application the ability to query the printer when it is in a busy state in order to correct whatever fault has
occurred.
Unsolicited status mode – This mechanism allows the application developer to program the printer to automatically
respond with a four byte status when certain conditions in the printer change.
Please see the subsequent sections for a more detailed description of these status commands. At the end of this status
commands section is a page entitled “Recognizing data from the printer”. This describes how to interpret what command
or setting (in the case of unsolicited status mode) triggered a response from the printer.
Batch mode
For RS-232C printers, these commands enable the printer to communicate with the host computer following the selected
handshaking protocol, either DTR/DSR or XON/XOFF. They are stored in the printer’s data buffer as they are received,
and are handled by the firmware in the order in which they are received.
When a fault occurs, the printer will go busy at the RS-232C interface and not respond to any of the batch mode printer
status commands. If the fault causing the busy condition can be cleared, such as by loading paper, or letting the thermal
printhead cool down, the printer will resume processing the data in its receive buffer.