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4 hardware, 1 standard model, Communication/power header – Matrix Orbital LCD0821 User Manual

Page 11: Alternate serial header, Protocol select jumpers

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4 Hardware

4.1 Standard Model

Communication/Power Header

Figure 6: Communication/Power Header

Table 4: Communication/Power Pinout

Pin Function

1

Vcc

2

Rx (SCL)

3

Tx (SDA)

4

Gnd

The Communication/Power Header provides a standard connector for interfacing to the LCD0821.
Voltage is applied through pins one and four of the four pin Communication/Power Header. Please
ensure the correct voltage input for your display by referencing Voltage Specifications before connecting
power. Pins two and three are reserved for serial transmission, using either the RS-232/TTL or clocking
data through the I²C protocol, depending on what has been selected by the Protocol Select Jumpers.
The versatile Tyco 640456-4-LF style header used can be mated to a number of connectors, the Molex
22-01-3047 for example.

Alternate Serial Header

Figure 7: Communication/Power Header

Table 5: Communication/Power Pinout

Pin Function

1

Gnd

2

Rx (SCL)

3

Vcc

Protocol Select Jumpers

The Protocol Select Jumpers provide the means necessary to toggle the LCD0821 between RS-232, TTL
and I²C protocols. As a default, the jumpers are set to RS-232 mode with solder jumps on the RS-232
jumpers. In order to place the display module in I²C mode you must first remove the solder jumps from
the RS-232 jumpers and then place them on the I

2

C jumpers. The display will now be in I²C mode and

have a default slave address of 80, unless changed with the appropriate command. Similarly, in order to
change the display to TTL mode, simply remove the zero ohm resistors from the RS-232 or I²C jumpers
and solder them to the TTL jumpers.