Hardware Reference
In-Depth Information
1) Turn the power ON.
2) Wait
15 ms after
V
DD
rises to 4.5 V.
3) Execute instruction “Function set,” with
DB
= “0011
>
−
−
−
−
”.
4) Wait
4.1 ms.
5) Execute instruction “Function set,” with
DB
= “0011
>
−
−
−
−
”.
6) Wait
s.
7) Execute instruction “Function set,” with
DB
= “0011
>
100
μ
−
−
−
−
”.
8) Execute instruction “Function set,” with
DB
= “0011
N F
−
−
” (choose
N
and
F
).
9) Execute instruction “Clear display,” with
DB
= “00000001”.
10) Execute instruction “Display on/off control,” with
DB
= “00001100”.
11) Execute instruction “Entry mode set,” with
DB
= “000001
I/D S
” (choose
I/D
and
S
).
(Some equivalent microcontrollers have a slightly simpler initialization.)
14.1.2 Typical FSM Structure for Alphanumeric LCD Drivers
A typical FSM structure for writing to the LCD of i gure 14.1 is shown in i gure 14.4a,
clocked by
E
at around 500 or 600 Hz. The seven states in the upper row constitute
the initialization sequence (compare those states to the sequence described above),
Figure 14.4
(a) Typical structure for an FSM that writes characters to the LCD of i gure 14.1. (b) Another
example for the actual data-writing states, displaying the digits of a clock.
