Remote Processing RPC-52 - Manual (Page 25)

CHAPTER 8 DISPLAY PORT
Page 23
Figure 8-1 Display interface
INTRODUCTION
RPBA SIC-52 a nd the RP C-52 ca n interfac e to a varie ty
of displays:
VF (vacuum florescent) character
LCD (liquid crystal) character
LCD gr aphics
Character display sizes range from four lines by 20
characters to four lines by 40 characters. The graphics
display supports 160 x 128 pixels. Remote Processing
supplies these displays with appropr iate cables.
A contr ast adjustme nt for L CD charac ter displays is b uilt
into the card. All displays connect to J6. An
appropriate cable connects a display to the RPC-52.
If a display is not used, J6 may be used for general
purpose digital I/O. P ort A and part of port B from an
82C55 are available.
The cable length to a display depends upon the amount
of current it requires. A significant amount of voltage
drop occurs with a long cable. VF and LC D graphics
c a bl e s s h ou ld b e l es s t ha n 2 f e et . A c ha r a ct e r L C D
display cable sh ould be less than 5 feet.
CONNECTING DISPLAYS
The display port is designed to supply all the lines
necessar y for V F and L CD displays. A custom cable
connects the RPC-52 to the display.
Displays purchased from Remote Processing include a
cable. You simply connect the 20 pin connector to the
RPC-52 L CD display port and the other end into the
display.
Additional w iring is usually r equired for LC D gr aphic
and VF character displays. This information is included
with the display. Information content is display
dependent. Below is general information on both.
Graphic displays require additional voltages not
generated on the RPC-52. These must be supplied
externally. An external contrast adjustment may be
necessary. Y ou may be able to connect these through
screw term inal block P6.
VF char acter displays require + 5 volts and ground to be
brought to connector P6. This may in the form of
external wires from the m ain power connector on the
board. Power is not supplied from the board due to the
danger of gr ound loops.
Additional information for commands m entioned in the
following text may be found in the RPBASIC-52
Softwar e Supplem ent in this man ual.
WRITING TO THE DISPLAY
The display type must first be set using the CON FIG
DISPLAY command. T he DISPLAY com mand is used
to print information. The display type is stored in the on
card serial EEP ROM . C ONF IG DISPL AY needs to be
done only once.
PROGRAMMING EXAMPLE
The example below is for a four line by 40 character
LCD display. Even though DISPL AY statements do not
end with a comma (, ), a < cr> < lf> sequence is not
sent. Use C R to forc e a retur n. A CR do es not scro ll
charac ters on a disp lay. You m ust position the cur sor to
the next line.
CONFIG DISPLAY X
10 STRING 200,30
20 $(0) = "Remote Processing display"
30 DISPLAY (1,2),$(0)
DISPLAY TYPES
RPBASIC-52' s software driver is based upon the
characteristics of the display family. Compatible VF and
LCD displays are shown below:
Manu fact. Model Type
Optrex DMC 40457 LCD 4 x 40
Optrex DMC 40202 LCD 2 x 40
IEEE 3601-90-080 VF 4 x 20
Optrex DMF 682N LCD 160W x 128D
DISPLAY CONNECTOR PIN OUT - J6
The displa y port uses an 82C5 5 for data and contr ol.
The table below lists a pin number and its intended
function. A display may not use all lines even though
they are available.