Processor Support ASIC

The processor support ASIC provides support for the main processor, and an interface between the main processor and the servo processor.

Shuffler ASIC and Swath Memory

The shuffler ASIC and the swath memory shuffle the row>oriented image data in the system memory into column>oriented nozzle data needed by the print cartridges. The shuffling is accomplished by copying an entire swath of image data from the system memory into the swath memory, then fetching the pixel data from swath memory for each cartridge nozzle according to the shuffle pattern in the ASIC address sequencer. The shuffled data is transferred serially to the nozzle>timing ASIC located on the carriage.

Input/Output Interfaces

The plotters have both a parallel (Bi>Tronics) and a serial (RS>232) interface. These I/Os are controlled by the main processor.

Parallel Input/Output Hardware The parallel interface is compliant with IEEE standard 1284 (Bi>Tronics).

The parallel port has a standard female 1284>B 36>pin connector (the same connector as standard Centronics).

Hosts with 1284>compliant parallel interfaces (including standard PCs with the appropriate parallel>port software) are able to communicate with the plotter bidirectionally. Hosts with standard Centronics hardware (such as traditional PCs) are able to operate with the plotter as they do with standard Centronics devices.

What is Bi Tronics Bi>Tronics is a signaling method for a speed>adaptive, fully interlocked, bidirectional parallel communications channel between a peripheral and a host. The features of Bi>Tronics are:

￿Provides the capability to send data from the host computer to the plotter at a higher speed, by shortening the signal timing values.

￿Provides a path for data to be sent from the plotter to the host, such as solicited and unsolicited status (media jam, plot finished, etc.)

￿Reduced user interaction: The host software can request information of the plotter directly (such as •amount of available memory?") instead of prompting the user.

￿The specification allows PCs with existing parallel>port hardware to participate in bidirectional communication with a peripheral by installing new parallel>port driver software; no new PC hardware is necessary.

The IEEE>1284 specification provides for two levels of compliance for the electrical characteristics of an interface. The interface for the plotters meets the Level 1 electrical requirements.

The IEEE>1284 specification defines five modes of operations for an interface. The interface for the plotters implements Compatibility and Nibble modes.

Host>to>peripheral data>transfer handshaking is performed by a hardware state machine. Peripheral>to>host handshaking is performed by the main processor in response to an interrupt.

5>24 Functional￿Overview

C3187>90000