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Page 4
EA eDIPTFT32-A
RS-232 INTERFACE
If the display is wired as shown
below, the RS-232 interface is
selected. The pin assignment is
specified in the table on the right.
The RxD and TxD lines lead CMOS
level (VDD) to a microcontroller, for
example, for direct connection.
If “genuine” RS-232 levels are
required (e.g. for connection to a
PC), an external level converter
(e.g. MAX232) is required.
Note:
The pins BAUD 0 to 2, ADR 0 to 2, DPOM,
DPROT and TEST/SBUF have an internal
pullup, which is why only the LO level
(0=GND) is to be actively applied. These
pins must be left open for a Hi level.
For RS232 operation (without
addressing) the pins ADR 0 to ADR 2
must be left open.
On pin 20 (SBUF) the display indicates
with a low level that data is ready to be
retrieved from the internal send buffer.
The line can be connected to an interrupt input
of the host system, for example.
BAUD RATES
The baud rate is set by means of pins 6, 7 and 8 (baud 0 to 2). The data
format is set permanently to 8 data bits, 1 stop bit, no parity.
RTS/CTS handshake lines are not required. The required control is
taken over by the integrated software protocol (see pages 10 and 11).
application example
Pinout eDIPTFT32-A: RS-232/RS-485 mode
Pin Symbol In/Out Function
Pin
Symbol
In/Out Function
1
GND
Ground Potential for logic (0V)
21
GND
Ground (=Pin 1)
2
VDD
Power supply for logic (+3,3V ... +5V)
22
VDD
Power supply (=Pin 2)
3
NC
do not connect
23
AIN1
In
analogue input 0..VDD
DC impedance 1MOhm
4
NC
do not connect
24
AIN2
5
RESET
In
L: Reset
25
OUT1 / MO8
Out
8 digital outputs
maximum current:
IOL = IOH = 10mA
alternativ up to 8 matrix
keyboard output lines
(reduces the digital
output lines, see chapter
external keyboard)
6
BAUD0
In
Baud Rate 0
26
OUT2 / MO7
7
BAUD1
In
Baud Rate 1
27
OUT3 / MO6
8
BAUD2
In
Baud Rate 2
28
OUT4 / MO5
9
ADR0
In
Address 0 for RS-485
29
OUT5 / MO4
10
RxD
In
Receive Data
30
OUT6 / MO3
11
TxD
Out
Transmit Data
31
OUT7 / MO2
12
EN485
Out
Transmit Enable for RS-485 driver
32
OUT8 / MO1
13
DPOM
In
L: disable PowerOnMacro
do not connect for normal operation
33
IN1 / MI8
In
8 digital inputs
open-drain with internal
pullup 20..50k
alternativ up to 8 matrix
keyboard input lines
(reduces the digital input
lines, see chapter
external keyboard)
14
ADR1
In
Address 1 for RS-485
34
IN2 / MI7
15
ADR2
In
Address 2 for RS-485
35
IN3 / MI6
16
BUZZ
Out
Buzzer output
36
IN4 / MI5
17 DPROT
In
L: Disable Smallprotokoll
do not connect for normal operation
37
IN5 / MI4
18
DNC
Out
L: internal, do not connect
38
IN6 / MI3
19
WP
In
L: Writeprotect for DataFlash
39
IN7 / MI2
20
TEST
SBUF
IN
Out
open-drain with internal pullup 20..50k
IN (Power-On) L: Testmode
OUT L: data in sendbuffer
40
IN8 / MI1
Baud Rates
Baud0 Baud1 Baud2
data format
8,N,1
1
0
0
2400
0
1
0
4800
1
1
0
9600
0
0
1
19200
1
0
1
38400
0
1
1
57600
1
1
1
115200
0
0
0
230400
