Table of Contents
Digital input-output module v3.3
(Version 3)
Digital i/o module is designed for simple tasks and basic process control. Module has three push-buttons and three LEDs, which can be used as digital inputs and outputs of microcontroller. Additionally to simple LEDs the module is equipped with 7-segment indicator and LCD display outputs. Digital i/o module is handy to use along with other modules enabling to control the output device behavior, like motors and display the sensor readings.
Module features:
- Green, yellow and red LED;
- Three push-button;
- 7-segment indicator;
- Alphanumeric LCD connector;
- Graphical LCD connector;
- Ultrasonic distance sensor connector.
Electrical connections
Controller module and Digital i/o module connection
Digital i/o module is connected with Controller module by one ribbon cable to port PA/PC/PG, which includes the 8-pin ports PA and PC and 3-pin port PG. The module is also powered by the same cable. If the module is connected correctly the on-board SMD LED +5V_OK has to light up. In other case the cable is probably wrongly connected.
Digital i/o module is equipped with three buttons S1, S2, S3 which are connected to ports PC0, PC1, PC2 accordingly. The other end of buttons are connected through the resistors to ground (logical 0). LED1, LED2 and LED3 on the module are connected to the ports PC3, PC4, PC5 accordingly. The anodes of LEDs are connected to the supply (logical 1).
Schematics of buttons and LEDs
Digital i/o board is equipped with 7-segment indicator, which is connected with microcontroller ports through the driver A6275. Driver data bus (S-IN) is connected to pin PC6, clock signal (CLK) to the pin PC7 and latch signal (LATCH) to pin PG2.
Schematics of 7-segment indicator
The module has two different connectors for port PA. The port is connected concurrently to separate pinout groups where one of them is connected through the voltage converter enabling to use 3.3 V devices (like graphical LCD). Another port PA pinout is connected directly to microcontroller port (5 V level) and is aligned according to standard 2 x 16 alphanumeric LCD. Two unused ports - PG0 and PG1 are grouped on the board together with ground and supply (starting from module version 3.3). Different devices can be connected to this connector, for example ultrasonic distance sensor. However while connecting the ultrasonic sensor great care has to be paid in connecting power supply plug correctly. In case of mixing up the ground and supply the sensor will be permanently damaged. For ultrasonic sensor, connect the black wire with ground (marked as GND on the board) and red wire with supply. Signal wires have to be connected with PG0 and PG1 ports.
Schematics of LCD
The back-light intensity of alphanumeric LCD is regulated with small potentiometer (LCD_BG) on the digital i/o board and graphical LCD back-light can be controlled by the software. Both LCD displays are connected to the port PA but only one at a time.
Connecting the module
While connecting the module it is suggested to follow the order as described below. Before connecting any cable make sure that the power is removed from Controller board.
- Connect the Digital i/o module with Controller module by using the ribbon cable.
- Connect LCD module with Digital i/o module (only one at a time)
- If needed connect the JTAG programmer with Controller module.
- Connect the power supply with Controller module.
Connecting the Digital i/o module
Connecting the LCDs
