40990901TH Rev.1 4 /3. CIRCUIT DESCRIPTION3.1 OutlineThe main control board controls the reception of data transferred through a host I/F and processescommand analysis, bit image development, raster buffer read. It also controls the engine and theoperator panel. Its block diagram is shown in Fig. 3-1 .(1) Reception controlThe OKIPAGE 10ex Printer can be equipped with one I/F port by adding an RS232C I/Foption board in addition to the Centronics I/F on the main control board.Either of the two I/F ports which receives data first can be used automatically.The other I/F port outputs a busy state signal.The parallel I/F port can specify the following item when set by the control panel:I-PRIME: Enabled/DisabledThe serial I/F port can specify the following item when set by the control panel:Flow control : DTRHI/DTR LO/XONXOFF/RBSTXONBaud rate : 300/600/1200/2400/4800/9600/19200 (Baud)Data bit : 7/8 (bits)Minimum busy time : 200/1000 (ms)Parity : NONE/ODD/EVENAn interface task stores all data received from the host into a receive buffer first.(2) Command analysis processingThe OKIPAGE 10ex Printer support PCL6 (Hewlett Packard LJ6P compatible).An edit task fetches data from the receive buffer, analyzes commands, and reconstructs thedata in such a way that print data are aligned from up to down and from right to left; then itwrites the resultant data into a page buffer with such control data as print position coordinate,font type, etc. added.(3) Font ProcessingWhen one page editing is finished, a developing task makes an engine start and fetches datafrom the page buffer synchronizing with a printing operation, then it developes the fetcheddata to a bit map as referring to data from a character generator, and writes the resultant datainto the raster buffer (of band buffer structure).(4) Raster buffer read.As controlling the engine operation, an engine task sends data from the raster buffer to theLED head.
