KANDA STK300, Руководство пользователя

Страница: 22 / 45

Page 22
Using LCD Connections
The header marked LCD interface is for a standard 2 X 16 LCD. The connections are shown on
the board and in the following table.
Connection
Name Function
0V Ground 0V
+5 Vcc - must be 5V
Vo Contrast
RS Register Select- A14
Wr Not Write
E Enable
D0 Data Bit 0
D1 Data Bit 1
D2 Data Bit 2
D3 Data Bit 3
D4 Data Bit 4
D5 Data Bit 5
D6 Data Bit 6
D7 Data Bit 7
The board is designed for use with an LCD with a Hitachi driver chip built-in, with a contrast pin
voltage of 0 to 5 Volts. The pot next to the LCD connector is used for contrast adjustment.
If you use a different LCD driver, it may have a different voltage contrast range. In order to
accommodate this, add a resistor to the board (shown above) and cut track on underside of board
- marked cut.
This board is not designed for use with back lit LCD modules, so the extra connections needed
are not included and the power supply will not supply the current required.
The LCD must be driven in Memory Mapped Mode as Read and Write are descite pins on the
Mega parts- see data sheet. If the crystal has been changed to a faster crystal frequency,
memory mapped operations will not work.
Using RS232
The connection supplied is a 9-way female D-type, so a “straight through” lead is required - not a
null-modem cable.
The Jumpers in the middle of the board, marked PE0 and PE1 must be set to RS232 not Port or
RXD and TXD will be disabled.
As this board has a 4 MHz crystal, the percentage error on the Baud Rate will be between 0.2 and
7.8%. Replacing the crystal with a 3.6846 MHz or 4.608 MHz crystal will reduce this error to zero
but may have EMC implications.
A standard (straight through) lead is required NOT a null-modem cable.