5
3
OUTLINE OF CIRCUITS
3.1
THERMAL HYSTERESIS CONTROL
When Line Thermal Head performs printing at high speed, heat remaining from printing which is one dot line before
may give some influence, resulting in blurred prints or trailing. This gate array, therefore, can serve to control
printing to the best result through monitoring state of operation of the preceding stage.
For printing of one dot line, one-dot-line data are transferred twice. The first data perform logical operation with
preceding data, serving as data for processing of print data for hysteresis supply. The second data substantially serve
for printing. Hysteresis supply (pre-pulse) and normal supply (main pulse) together compose one dot line supply.
To transfer data of one dot line, carry it out at high speed from CPU to the gate array by DMA, etc..
3.2
HEAD STROBE CONTROL
As one system to drive Line Thermal Head, one dot line is split into two or more blocks and current is supplied to each
of these blocks. Supply current capacity, thus, can be reduced. Switching in timing of current supply to these split
blocks is automatically performed by the gate array.
This is also equipped with a circuit which serves to prevent the thermal head from being damaged on occurrence of
strobe signal control failure due to CPU excursion, etc..
3.3
BIT DATA PROCESSING FUNCTION
This product is further provided with data processing function which is effective in developing printing data in bits.
For example, 8-bit data 180° turning function, 90° turning function, and 16-bit conversion (double font letter) function
are easily realized.
3.4
8-BIT PARALLEL INPUT CIRCUIT
Receiving of signals from Host is carried out in 8-bit parallel system. Received data from Host are STB, 8-bit data,
while data sent to Host are BUSY, ACK. When data are sent from Host, BUSY is output automatically. When CPU
starts reading the data, ACK is automatically output and BUSY is cancelled.
Use a general purpose port or CPU to deal with other control signals.
3.5
GENERAL PURPOSE I/O CIRCUITS
This is provided with 8-bit I/O usable for various kinds of input/output. As some pins are shared with other functions,
confirm each application before using it.
