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For elongated character printing, ROME2 is coincident with
the STROBE signal. This combined with the fact that the
DCW timing signals from LSI chip ME16 are twice as long
during elongated character mode, causes the printed char-
acter to be twice as wide as normal characters. An example
of the character (Y), both in normal and elongated style,
is shown in Figure 4-7.
9
~
NORMAL"y"
ELONGATED"y"
Figure 4-7. NORMAL AND ELONGATED CHARACTERS
The seven outputs from all four ROMls are wire ORed together and
gated out to the Power Driver board as signals CGI-CG7.
In normal oper-
ation, the STROBE or DLYSTB signal gates the addressed dot column to the
Power Driver board. The input to ME7 pins 1 and 2 is normally low holding
the output constantly high, enabling the output CG gates.
If, however,
there is a failure in the -12V supply, then ME7-1 and 2 goes high forcing
ME7-3 low disabling the CG gates.
Note, the optional buffers and diodes (shown on the schematic)
associated with the ROM elements are needed only if a +12V ROM is used.
If only +5V ROMls are used, these additional buffers and diodes are not
needed.
4-20
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