Introduction; Printer Controller Pcba; Microprocessor And Related Circuits - Printronix T3204 Maintenance Manual

Introduction

This section describes the operation of the Printer Controller PCBA which is
responsible for host data processing, forms motion control, monitoring of
various sensors and image processing.

Printer Controller PCBA

In the design of the printer, the majority of the electronic functions are
combined on a single circuit board (the Printer Controller PCBA), utilizing the
i960JA type microprocessor.
The microprocessor is responsible for overseeing the data flow throughout
the system; for processing and formatting print data; for managing the print
cycle in which print data is sent to the printhead and the Printhead elements
activated; and for monitoring the sensors for alarm conditions.
This section provides an overview of the hardware functions located on the
Printer Controller PCBA.

Microprocessor and Related Circuits

The main devices and functions located on the Printer Controller PCBA are
listed below:
1. 80960JA Microprocessor and Microchip PIC16C55 Microcontroller
2. Address Latches
3. 1 MByte of DRAM (expandable on board with a 4 or 16 MByte memory
option board, providing a total of 5 MBytes or 17 MBytes of DRAM)
4. DRAM Address Multiplexer
5. 2 MBytes of EPROM
6. 128 KByte of NVRAM
7. Memory cartridge interface
8. ST16C1451CJ UART
9. FIFO and SRAM
10. Ribbon Sensor
11. Operator Panel Controls
12. Paper Edge Sensor
13. Label Present Sensor
14. Options outputs (paper cutter, ribbon saver, parallel host interface and
label present sensor)
15. Switch inputs
16. Real time clock
17. Start of print adjustment
18. Stepping motor control lines
19. Thermal printhead control circuits
20. RS232 driver and receiver
21. RS422 driver and receiver
22. Analog to digital converter
23. Programmable switches and jumpers
8–2 Circuit Description