Initializing Operation; Controlling The Interface; Print Head Control Drive Circuit - OKIDATA ML1120 Maintenance Manual

2.2.2 Initializing operation

The initializing operation is performed for this printer when the power is turned ON and when I-PRIME for
the parallel interface is input from the Host.
In the initializing operation, the RST-N signal is first output from the reset IC (RST-1 pin) to reset CPU.
The program start after CPU is reset.
The program sets the LSI mode including CPU, checks the memory (ROM/RAM), and initializes the
RAM. Then it determines the phase of the LF motor and performs homing for the carriage. Finally, it
determines the interface signal (outputs ACK signal and BUSY signal), illuminates the A lamp, notifies
the Host that it is in a mode that can receive data (data standby mode), and completes initialization.
(Paper-end mode when using continuous form is excluded.)

2.2.3 Controlling the interface

1) Parallel interface
Data from the interface is input from the connector (CENT) and is read in the timing of the
STB-N signal by the interface, print head, and LSI for motor control (MG74Q514-131).
When this signal is being process, the BUSY signal goes ON. When the process is completed,
the BUSY signal goes OFF, sends an ACK-N signal, and waits to receive the next data.
(E.g.) When [I/F timing] is set to [A-B] in an English menu.
DATA1~8
STROBE-N
BUSY
ACK-N

2.2.4 Print head control drive circuit

This circuit produces the print timing and drive time from LSI, drives the head magnet that corresponds to
HEAD 1~9 with HD01-09-P signal and HDCOM1~9 - P signal and prints.
As the print head is dispersed and allocated in each group, the nine groups are controlled individually.
43471801TH Rev.1
Oki Data CONFIDENTIAL
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