User`s manual

4.8 RS485 port
The RS485 interface IC (SN75176) is not installed. To make RS485 work, user has to install
the U9, shorting the J27 and install a terminal resistor (100 ohm) at the last node.
4.9 External SPI interface
SPI port (J10) pinouts are as follows:
Pin 1 MISO Pin 2 VCC (5V)
Pin 3 SPSLK Pin 4 MOSI
Pin 5 /SS Pin 6 VSS (GND)
4.10 LCD display (optinal)
Port K is an 8-bit bi-directional port. It’s used for the LCD display module. If the port is not used
for the LCD display, it can be used as a general-purpose I/O port.
The pinouts of J1 are as follows:
Pin 1 GND
Pin 2 VCC (5V)
Pin 3 Via a 220 Ohm resistor to GND
Pin 4 PK0 RS pin for LCD module
Pin 5 GND Write only for LCD module
Pin 6 PK1 EN pin for LCD module
Pin 7 Not used
Pin 8 Not used
Pin 9 Not used
Pin 10 Mot used
Pin 11 PK2 DB4 pin for LCD module
Pin 12 PK3 DB5 pin for LCD module
Pin 13 PK4 DB6 pin for LCD module
Pin 14 PK5 DB7 pin for LCD module
Please notice that PK2-PK5 (not PK4-PK7) are used to drive DB4-DB7 of the LCD module.
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