Table of Contents
Advertisement
REV.-A
2.4.1.2 Paper Feed Motor Control
The block diagram for the paper feed motor control circuit is shown in Figure 2-25. In the main circuit,
the paper feed motor phase switching is not directly carried out by the CPU, but is instead carried out
by the DCU (2A) according to the pulse sent from the MMU (8B). The DCU is enabled by the MMIO 03
signal sent LOW from the MMU. After the DCU first sets addresses AO-A3, it sets the excitation method
(2-2 phase or 1-2 phase) and the rotation direction (CW or CCW) according to the SCK/RCK port settings
and, if the pulse (PTFM signal) is input from the MMU to the TM 1 terminal, automatic phase switching
of the stepping motor is carried out.
The operation wave forms for the TM 1 and DFA/A signals are shown in Figure 2-26. Furthermore,
HIGH/LOW is set to ports P 1-P3 according to similar address settings and the SCK/RCK port settings.
Accordingly, control of the constant-current circuit is carried out.
The paper feed motor controls bi-directional rotation and paper feed stop at selected positions. From
start to finish of one rotation sequence, there are five modes:
1. Pre-drive rush
2. Acceleration control
3. Deceleration control
4. Constant speed control
5. Post-drive rush
The phase switching time settings (PFTM pulse switching time) are different for each mode. Refer to
Figure 2-27. As Figure 2-27 shows, the firmware determines time setting data (PFTM pulse switching
time) for five speeds and selects the correct speed for the drive state (micro feed, continuous feed,
one-line feed, and CSF). Constant-current control is carried out to achieve phase switching, to vary the
motor torque, and to regulate the level.
Advertisement
Table of Contents
