Star Micronics LC-8521, Technical Manual

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1. Block Diagram
The block diagram of this printer is shown in Fig. 2-1.
Fig. 2-1 Block Diagram
(1) Main Logic Board
This board receives data from the host computer and stores it in the RAM in the order it arrives. The CPU on this
board reads the data from the RAM, and edits it according to the program stored in the ROM.
When editing is completed, various drive signals from the CPU are sent to the printer mechanism to perform
printing.
Explanation
• CPU TMP95C061BEF
Controls this printer.
• UVE-PROM 1M bit
Contains the program which executes control of the printer. UVE-PROM is not provided with some versions of the
software.
• Masked ROM 8M bit
Contains the character font.
• EE-PROM KM93C46 64
×
16 bits
Contains the data (EDS data and so on) in the memory switch.
• RAM 1M bit
Used as a stack area, work area and data buffer of the CPU.
• Parallel interface
• Gate array (custom IC)
Inputs/outputs several signals.
• Driver
The data edited by the CPU and gate array are sent to the printer mechanism after conversion to the signal for the
print head drive and motor drives.
(2) Control panel board
Panel circuit for manual control of the printer.
(3) Printer Mechanism
Consists of a print head, carriage motor, paper feed motor, and detectors.
(4) Power Supply Unit
Converts AC power to 40VDC and 5VDC.
Data (From Host Computer)
LED
Switch
Control
panel board
Power
supply unit
AC Power
Parallel
interface
Driver
Gate array
CPU
RAM
Masked ROM
8M
EE-PROM
Paper feed
motor
Carriage
motor
Print head
Main logic board
Printer
mechanism
Detectors
UVE-PROM
1M