Main control unit

OVERVIEW

This scanner is controlled by a 80C186 MPU. This scanner consists of a ROM as a program area, internal registers, an external RAM as a work area, gate arrays for the MPU peripheral and video circuits, dither processing and γ conversion RAMs, and error diffusion.

Interface control

RS-232C and video interface

RS-232C interface

The RS-232C interface consists of an ACIA( 8251) and driver-receiver ICs (145406).

Video interface

This scanner processes a document by the 256-step gray scale. Images are processed in a way specified by the interface or the operator panel and transferred serially in eight-bit units. Eight-bit data has V0 at the left end and V7 at the right end and strobed by VCL.

HGATE ensures the validity of data in the main scanning and

VGATE for the subscanning.

The scanner status is basically reported by the RS-232C interface. An equipment error is reported to the host computer by a FAIL signal in case that RS-232C communication failed. See Chapter 3 for detailed specifications of the interfaces.

Resolution

The basic resolution of this scanner is 200dpi. The resolution can be changed to 240, 300, or 400dpi from the host computer or the operator panel.

The resolution in the subscanning direction is achieved by changing the document transport speed.

When the image processing circuit II (IPC II) option is installed, the linear density is changed by setting the parameter to its internal circuit.

M3099EX/EH OEM Manual

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