Library Description

Library performs the control of the 4D Systems LCD displays via UART interface by sending the determined commands. The commands can read the objects and write the desired value to the objects, also they support sending the report from the device to the host. Before we start to use this library, first we must perform the LCD display programming. The UART baud rate on LCD and UART baud rate on the host device must be the same. The user can use our demo application for the 4D Systems LCD display, which simulates the speed measurement. For more details check the documentation.

Key functions

• void c4d_writeObj( T_C4D_OBJ_P obj ) - Function writes the desired value to the desired object.
• void c4d_readObj( T_C4D_OBJ_P obj ) - Function reads the value of the desired object.
• uint8_t c4d_sendCommand( uint8_t _command, uint8_t *dataIn, uint8_t nBytes ) - Function sends command to the display.

Example description

The application is composed of three sections:

• System Initialization - Initializes peripherals and pins.
• Application Initialization - Initializes UART driver, configures timer and puts all objects on the display to the inactive state (initializes display). Also waits about 5 seconds to stabilize the display.
• Application Task - (code snippet) - Performs the display control. The application represents speed measurement. First checks isstart button enabled, and when is it true, reads the value of the slider object and represents that value to the other objects. The slider value is controled by the timer. The user should put Start switch to active state (start application) when Ready LED becomes green. Note: Before you start using this code, first you must perform the display programming by using workshop application. The display programming will define all objects and show your desired objects on the display. Also the microSD card is necessary when you start the display programming, and must be formated as FAT16. When programming is finished puts the microSD card on the display device and then you can start to use this example,
  to control all objects on the display.

void applicationTask()
{
 c4d_readObj( (T_C4D_OBJ_P)&dipswitch0 );

 if (dipswitch0.objValue != _C4D_INACTIVE_STATE)
 {
 if (enCheck == _C4D_INACTIVE_STATE)
 {
 led0.objValue = _C4D_ACTIVE_STATE;
 c4d_writeObj( (T_C4D_OBJ_P)&led0 );
 enCheck = _C4D_ACTIVE_STATE;
 TIM2_CR1.CEN = _C4D_ACTIVE_STATE;
 }

 if (slider0.objValue != prevState)
 {
 leddigits0.objValue = slider0.objValue * 10;
 coolgauge0.objValue = slider0.objValue;

 if (slider0.objValue != _C4D_INACTIVE_STATE)
 {
 userled2.objValue = _C4D_ACTIVE_STATE;
 }
 else
 {
 userled2.objValue = _C4D_INACTIVE_STATE;
 }
 if (slider0.objValue >= 100)
 {
 userled1.objValue = _C4D_ACTIVE_STATE;
 }
 else
 {
 userled1.objValue = _C4D_INACTIVE_STATE;
 }
 if (slider0.objValue >= 200)
 {
 userled0.objValue = _C4D_ACTIVE_STATE;
 }
 else
 {
 userled0.objValue = _C4D_INACTIVE_STATE;
 }

 c4d_writeObj( (T_C4D_OBJ_P)&slider0 );
 c4d_writeObj( (T_C4D_OBJ_P)&leddigits0 );
 c4d_writeObj( (T_C4D_OBJ_P)&coolgauge0 );
 c4d_writeObj( (T_C4D_OBJ_P)&userled0 );
 c4d_writeObj( (T_C4D_OBJ_P)&userled1 );
 c4d_writeObj( (T_C4D_OBJ_P)&userled2 );
 prevState = slider0.objValue;
 }
 }
 else if (enCheck == _C4D_ACTIVE_STATE)
 {
 TIM2_CR1.CEN = _C4D_INACTIVE_STATE;
 slider0.objValue = _C4D_INACTIVE_STATE;
 leddigits0.objValue = _C4D_INACTIVE_STATE;
 coolgauge0.objValue = _C4D_INACTIVE_STATE;
 userled0.objValue = _C4D_INACTIVE_STATE;
 userled1.objValue = _C4D_INACTIVE_STATE;
 userled2.objValue = _C4D_INACTIVE_STATE;
 led0.objValue = _C4D_INACTIVE_STATE;
 prevState = slider0.objValue;
 enCheck = _C4D_INACTIVE_STATE;
 transmission1 = _C4D_INACTIVE_STATE;
 transmission2 = _C4D_INACTIVE_STATE;
 transmission3 = _C4D_INACTIVE_STATE;

 c4d_writeObj( (T_C4D_OBJ_P)&slider0 );
 c4d_writeObj( (T_C4D_OBJ_P)&leddigits0 );
 c4d_writeObj( (T_C4D_OBJ_P)&coolgauge0 );
 c4d_writeObj( (T_C4D_OBJ_P)&userled0 );
 c4d_writeObj( (T_C4D_OBJ_P)&userled1 );
 c4d_writeObj( (T_C4D_OBJ_P)&userled2 );
 c4d_writeObj( (T_C4D_OBJ_P)&led0 );
 }
}

Additional Functions :

• Timer interrupt function is used to control the slider object value and on that way we simulate the speed changing.

Other MikroElektronika libraries used in the example:

• UART

Additional notes and information

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.