HP 750 - Manual (Page 44)

5-2 Functional Overview C4705-90000
Introduction
This chapter contains a simplified description of the DesignJet 700, 750C and 750C Plus
plotters and DesignJet 755CM printer circuits and mechanical functions. Mechanical and
Printed Circuit Assembly (PCA) overviews present a functional description of how the plotter
operates.
Simplified Description of Circuits
Communications
HP DesignJet 700, 750C, 750C Plus and 755CM circuits communicate with an external
controller by way of either a BiĆtronics or an RSĆ232ĆC interface.
BiĆtronics is handled by a separate gate array.
RSĆ232ĆC communications are handled by a universal asynchronous receiverĆtransmitter
(UART) and baud rate generator built into the processorĆsupport applicationĆspecific
integrated circuit (ASIC).
If an approved modular input/output (MIO) printed circuit assembly is installed, the circuits
can communicate via an HPĆIB interface or can be connected to a network. The main
processor reads BiĆtronics, HPĆIB, and Ethernet communications through the port it uses to
read memories (ROM or DRAM).
Plotting
HP DesignJet 700, 750C, 750C Plus and 755CM plotters/printers accept plots in the following
forms:
D HewlettĆPackard Graphics Language (HPĆGL).
D HewlettĆPackard Graphics Language 2 (HPĆGL/2).
D HewlettĆPackard Raster Transfer Language (HP RTL).
The main processor converts the plot into an internal format and stores the entire plot, in its
dynamic randomĆaccess memory (DRAM) - except for special types of RTL plots which may
begin to print while they are still being received.
Then, it transfers the plot, one swath at a time, into the swath RAM via the
processorĆsupport ASIC.