12
4.7
PRINT DATA TRANSFER METHOD
When printing is performed with Line Thermal Head at high speed, it is necessary for you either to control printing
speed so that heat from printing of the preceding stage does not give any influence or to perform stored heat correction
so that remaining heat is eliminated. This gate array is provided with a circuit which holds printing energy at low
level to attain high-quality printing when power is supplied for the main stage printing to the dot which has been
subject to power supply also in the preceding stage.
Power supply to Line Thermal Head included pre-pulse and main pulse. To those dots to which power has not been
supplied in the preceding stage, "pre-pulse + main pulse" is supplied. To those dots to which power has been
supplied in the preceding stage, main pulse alone is supplied. Head Control Mode Registers for switching main pulse
and pre-pulse, etc. are assigned in Address XX07h.
Assignment of Head Control Mode Register in each bit is as follows:
Data transfer to Thermal Head is performed as follows:
1.
Print data for 1 dot line or multiple dot lines are developed in memory beforehand.
2.
HOS1/ HOS0 of Head Control Mode Registers are set to "0, 1" to assign pre-pulse.
3.
DMA request is given.
With "#OFFh" being written in Address XX01h, one-shot from DRQ pin is output. DRQ signal is a request of
1-byte DMA transfer.
4.
Print data developed beforehand from CPU are transferred to print data buffer (Address XX00h) by data bus.
5.
They are subject to parallel/ serial conversion inside the gate array and are transferred to Head in 1-byte serial.
(Transferred in 4MHz clock rate)
6.
With data received and transfer started, Request signal (DRQ) of next data is given. Next data are written in the
print data buffer.
7.
On completion of data transfer of 1 dot line, data are latched to Head and strobe control starts. (Pre-pulse
supply)
8.
During pre-pulse supply, print data for main pulse are transferred. The transfer method is the same as that for
pre-pulse, except that Head Control Registers HOS1/ HOS0 are set to "0, 0" and main pulse is assigned for
transfer.
9.
On completion of transfer and pre-pulse supply, print data are latched to Head before main pulse supply.
10.
On start of printing or on printing where line feed, etc. has eliminated influence of printing of the preceding stage,
pre-pulse and main pulse are supplied under main pulse assignment.
Note) On supply of power, to clear, once, the gate array internal buffer, write "00h" into the print data buffer with Head
Control Mode Register SAbit being held at "0".
Содержание CBM-202LA s
Страница 20: ...20 5 OPERATION TIMING Operation timings immediately following initialization are shown below ...
Страница 23: ...23 7 REFERENTIAL CIRCUIT DIAGRAM ...
Страница 24: ...24 ...
