PCF2114AU/10 PHILIPS [NXP Semiconductors], PCF2114AU/10 Datasheet - Page 42

• Manufacturer Part Number: PCF2114AU/10
• Description: LCD controller/drivers
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
18.1
Table 6 shows an example of a 1-line display in 8-bit
operation. The PCF2116 functions must be set by the
‘Function set’ instruction prior to display. Since the display
data RAM can store data for 80 characters, the RAM can
be used for advertising displays when combined with
display shift operation. Since the display shift operation
changes display position only and DDRAM contents
remain unchanged, display data entered first can be
displayed when the Return Home operation is performed.
18.2
The program must set functions prior to 4-bit operation.
Table 5 shows an example. When power is turned on, 8-bit
operation is automatically selected and the PCF2116
attempts to perform the first write as an 8-bit operation.
Since nothing is connected to DB0 to DB3, a rewrite is
then required. However, since one operation is completed
in two accesses of 4-bit operation, a rewrite is required to
set the functions (see Table 5 step 3).
Thus, DB4 to DB7 of the function set are written twice.
Table 5 4-bit operation, 1-line display example; using internal reset
1997 Apr 07
STEP
LCD controller/drivers
1
2
3
4
5
6
8-bit operation, 1-line display using internal
reset
4-bit operation, 1-line display using internal
reset
power supply on (PCF2116 is initialized by
the internal reset circuit)
function set
function set
display on/off control
entry mode set
write data to CGRAM/DDRAM
RS
0
0
0
0
0
0
0
1
1
R/W
0
0
0
0
0
0
0
0
0
INSTRUCTION
DB7
0
0
0
0
1
0
0
0
0
DB6
0
0
0
0
1
0
1
1
0
DB5
1
1
0
0
1
0
1
0
0
DB4
0
0
0
0
0
0
0
1
0
_
_
P_
DISPLAY
42
18.3
For a 2-line display, the cursor automatically moves from
the first to the second line after the 40
has been written. Thus, if there are only 8 characters in the
first line, the DDRAM address must be set after the eighth
character is completed (see Table 7). Note that both lines
of the display are always shifted together; data does not
shift from one line to the other.
18.4
A control byte is required with most instructions
(see Table 8).
18.5
If the power supply conditions for correctly operating the
internal reset circuit are not met, the PCF2116 must be
initialized by instruction. Tables 9 and 10 show how this
may be performed for 8-bit and 4-bit operation.
8-bit operation, 2-line display
I
Initializing by instruction
Initialized. No display appears.
Sets to 4-bit operation. In this instance operation
is handled as 8-bits by initialization and only this
instruction completes with one write.
Sets to 4-bit operation, selects 1-line display and
V
and resetting is needed.
Turns on display and cursor. Entire display is
blank after initialization.
Sets mode to increment the address by 1 and to
shift the cursor to the right at the time of write to
the DD/CGRAM. Display is not shifted.
Writes ‘P’. The DDRAM has already been
selected by initialization at power-on. The cursor
is incremented by 1 and shifted to the right.
2
C operation, 1-line display
LCD
= V
0
. 4-bit operation starts from this point
OPERATION
PCF2116 family
Product specification
th
digit of the first line