2.3 Compiler mikroC pro for PIC
The first thing you need to write a program for the microcontroller is a PC program which understands the programming language you use, C in this case, and provides a window for writing program. Besides, the software must 'know' the architecture of the microcontroller in use. In this case, you need a compiler for C language.
There is no compiler to be used for only one concrete microcontroller as there is no compiler to be used for all microcontrollers. It’s all about software used to program a group of similar microcontrollers of one manufacturer. This book gives description of the mikroC PRO for PIC compiler. As the name suggests, the compiler is intended for writing programs for PIC microcontrollers in C language. It is provided with all data on internal architecture of these microcontrollers, operation of particular circuits, instruction set, names of registers, their accurate addresses, pinouts etc. When you start up the compiler, the next thing to do is to select a chip from the list and operating frequency and of course - to write a program in C language. The installation of mikroC PRO for PIC is similar to the installation of any Windows program:
IDE FOR MIKROC PRO FOR PIC
This is what you get when you start up IDE for mikroC PRO for PIC for the very first time:
PROJECT MANAGER
A program written in mikroC compiler is not a separate document, but part of a project which includes Hex code, assembly code, header and other files. Some of them are created during the operation of compiler, while some are imported from other programs. However, the Project Manager Window enables you to handle them all. It is sufficient to right click any folder and select the option you need for your project.
CODE EXPLORER
The Code Explorer window enables you to easily locate functions and procedures within long programs. For example, if you look for a function used in the program, just double click its name in this window, and the cursor will be automatically positioned at appropriate point in the program.
PROJECT SETTINGS
Device - When you select the microcontroller, the compiler automatically knows which definition file, containing all SFR registers for specific MCU, their memory addresses and similar, to use.
Oscillator - This option is used to select the operating speed of the microcontroller. On the basis of it, the compiler makes changes in the configuration word. The operating speed is set so as to enable the microcontroller’s internal oscillator to operate with selected quartz crystal.
Build type - release After the process of compilation is complete, the compiler has no influence on the program execution. For the purpose of debugging, a software simulator can be used.
In order to enable the compiler to operate successfully, it is necessary to provide it with basic information on the microcontroller in use as well as with the information on what is expected from it after the process of compilation:
Build type - ICD debug: When the process of compilation is complete and the microcontroller is programmed, the compiler remains connected to the microcontroller and still can affect its operation. The connection is established via programmer which is connected to the PC via USB cable. A software making all this work is called the ICD (In Circuit Debugger). It enables the program to be executed step by step and provides an access to the current content of all registers of the microcontroller. Simulation is not carried out, their contents is literally read in true MCU controlling true device.
CODE EDITOR
A Code Editor is a central part of the compiler window used for writing a program. A large number of options used for setting its function and layout can be found in the Tools/Options menu [F12].SOFTWARE SIMULATOR
Prior to starting up the simulator, select the appropriate mode in the Project Settings Window (Build type - release) and click the Run /Start Debugger option.
The compiler will be automatically set in simulation mode. As such, it monitors the state of all register bits. It also enables you to execute the program step by step while monitoring the operation of the microcontroller on the screen (i.e. simulation of operation).
A few icons, used only for the operation of this simulator, will be added to the toolbar when setting the compiler in this mode.
They have the following meanings:
Step Into - Click on this icon executes one program line in which the cursor is positioned.
Step Over - This command is similar to the previous one. If the cursor is positioned in the line which calls a program routine than it will be executed first and the program proceeds with execution at the first next program line. It seems as if one program line is skipped even though the whole routine is executed. As a result, the state of registers change. This command is commonly used when it is necessary to speed up the execution of long program loops.
Run To Cursor - This command is used to execute a particular part of the program, i.e. from the last executed line -to the line in which the cursor is placed.
Step out - By clicking this icon, the program exits routine being currently executed.
The simulator and debugger have the same function to monitor the state of registers during program execution. The difference is that the simulator executes the program on the PC, while the debugger uses a true microcontroller. Any change of a pin logic state is reflected on appropriate register (port). As the Watch Window allows you to monitor the state of all registers it is easy to check whether a pin is set to zero or one. In order to activate this window it is necessary to select View/Windows and click the Watch Values option. Then you can make a list of registers the state of which you want to monitor.
If you want to find out how long it takes for the microcontroller to execute a part of the program, select the Run/View Stopwatch option. A window as shown in figure on the right will appear. Do you know how the stopwatch works? Well, it’s as simple as that.
COMPILER’S TOOLS
This compiler provides special tools which considerably simplify the process of writing a program. All these tools are available from theTools menu. In the following text we are going to give a brief description of all of them.PICFLASH PROGRAMMER
PICflash programmer is a stand-alone program which can operate independently of the compiler, i.e. it can be used as a separate program. However, in this case, its operation is closely related to the operation of the compiler so that it can be activated from within the compiler itself. If installed, the PIC flash programmer is activated by selecting Tools/me_Programmer or pressing [F11]. A window that appears contains options to be used for the process of programming microcontrollers.
USART TERMINAL
The USART terminal is a replacement for the standard Windows Hyper Terminal. It can be used for checking the operation of the microcontroller which uses USART communication. Such a microcontroller is built in a device and connected to the RS232 connector on PC over serial cable. The USART terminal window, shown on the right, contains options for setting serial communication and for displaying sent/received data.
EEPROM EDITOR
If you select the EEPROM Editor option from the Toolsmenu, a window, as shown in figure on the right, will appear. This is how the EEPROM memory within the microcontroller looks like. If you want to change its contents after loading the program into the microcontroller this is the right place to do it. If a new content is a data of specific type (char, int or double), then you should select it, enter the value in the Edit Value field and click Edit. Then click the Save button to save the data as a document with .hex extension. If the Use EEPROM in Project option is active, the data will be automatically loaded into the chip during the process of programming.
ASCII CHART
If you need numerical representation of any ASCII character, just select the appropriate option from the Tools menu and the table, as shown in figure below, will appear. As seen, the characters representing numbers have curious equivalents. For this reason, program command for displaying number 7 on an LCD display will not display anything similar this number. Instead, the equivalent of the command BEL will be displayed. If you send the same number as a character, you will get the expected result - the number 7. Accordingly, if you want to display a number without previously converting it into character, then it is necessary to add the number 48 to each digit the number consists of.
SEVEN SEGMENT EDITOR
A seven segment editor enables you to easily find out which number is necessary to be set on an output port in order to display a desired symbol. Of course, what goes without saying is that port pins must be connected to display segments properly. You just have to place the cursor on any display segment and click it. The number that you should copy to the program will be shown immediately. That’s all.
LCD CUSTOM CHARACTER
Apart from the standard characters, the microcontroller can also send characters created on your own to a display. By selecting the LCD custom character tool you will spare yourself from tedious work on creating functions for sending appropriate code to a display. Just create a symbol by clicking small squares in the LCD custom character window, select position and row and click the GENERATE button. The required code appears in another window. No more clicks are needed. Copy to Clipboard - Paste...
GRAPHIC LCD BITMAP GENERATOR
This is another irreplaceable tool in the event that the microcontroller you are writing program for uses graphic LCD display (GLCD). This tool enables you to display any bitmap easily. In order to take advantage of it, select Tools/Glcd Bitmap Editor and appropriate window appears. Select type of display to be used and load a bitmap. The bitmap must be monochromatic and in resolution specified (128 x 64 pixels in this example). Further procedure is the same as in the example above Copy to Clipboard...
LIBRARIES
One of the most useful options of this program is Library Manager and surely deserves our attention.
It is previously mentioned that the main advantage of the higher programming languages such as C is that these enable you to use the knowledge and work of other people. Function libraries are the best example of it. If you need a function to perform certain task while writing a program, you just have to look for it within some of the libraries which are integrated in the compiler and use it. For example, if you need a function to generate sound on some of the pins, open the Sound library in the Library Manager window and double click the appropriate function Sound_Play. A detailed description of this function appears on the screen. Copy it to your program and set appropriate parameters. If this library is checked, its functions will be automatically recognized during the process of compiling so that it is not necessary to use the #include command.
STANDARD ANSI C LIBRARIES
Standard ANSI C libraries includes standard functions of C language:| LIBRARY | DESCRIPTION |
|---|---|
| ANSI C Ctype Library | Mainly used for testing or data conversion |
| ANSI C Math Library | Used for floating point mathematical operations |
| ANSI C Stdlib Library | Contains standard library functions |
| ANSI C String Library | Used to perform string and memory manipulation operations |
MISCELLANEOUS LIBRARIES
Miscellaneous libraries contain some of the general-purpose functions which are not included in standard ANSI C libraries:| LIBRARY | DESCRIPTION |
|---|---|
| Button Library | Used for a project development |
| Conversion Library | Used for data type conversion |
| Sprint Library | Used for easy data formatting |
| PrintOut Library | Used for easy data formatting and printing |
| Time Library | Used for time calculations (UNIX time format) |
| Trigonometry Library | Used for fundamental trigonometry functions implementation |
| Setjmp Library | Used for program jumping |
HARDWARE SPECIFIC LIBRARIES
Hardware specific libraries include functions intended to be used for controlling the operation of various hadware modules:| LIBRARY | DESCRIPTION |
|---|---|
| ADC Library | Used for A/D converter operation |
| CAN Library | Used for operation with CAN module |
| CANSPI Library | Used for operation with external CAN module (MCP2515 or MCP2510) |
| Compact Flash Library | Used for operation with Compact Flash memory cards |
| EEPROM Library | Used for operation with built-in EEPROM memory |
| EthernetPIC18FxxJ60 Library | Used for operation with built-in Ethernet module |
| Flash Memory Library | Used for operation with built-in Flash memory |
| Graphic Lcd Library | Used for operation with graphic LCD module with 128x64 resolution |
| I2C Library | Used for operation with built-in serial communication module I2C |
| Keypad Library | Used for operation with keyboard (4x4 push buttons) |
| Lcd Library | Used for operation with LCD display (2x16 characters) |
| Manchester Code Library | Used for communication using Manchester code |
| Multi Media Card Library | Used for operation with multimedia MMC flash cards |
| One Wire Library | Used for operation with circuits using One Wire serial communication |
| Port Expander Library | Used for operation with port expander MCP23S17 |
| PS/2 Library | Used for operation with standard keyboard PS/2 |
| PWM Library | Used for operation with built-in PWM module |
| RS-485 Library | Used for operation with modules using RS485 serial communication |
| Software I2C Library | Used for I2C software simulation |
| Software SPI Library | Used for SPI software simulation |
| Software UART Library | Used for UART software simulation |
| Sound Library | Used for audio signal generation |
| SPI Library | Used for operation with built-in SPI module |
| SPI Ethernet Library | Used for SPI communication with ETHERNET module (ENC28J60) |
| SPI Graphic Lcd Library | Used for 4-bit SPI communication with graphic LCD display |
| SPI Lcd Library | Used for 4-bit SPI communication with LCD display (2x16 characters) |
| SPI Lcd8 Library | Used for 8-bit SPI communication with LCD display |
| SPI 6963C Graphic Lcd Library | Used for SPI communication with graphic LCD display |
| UART Library | Used for operation with built-in UART module |
| USB Hid Library | Used for operation with built-in USB module |
ACCESSING INDIVIDUAL BITS
The mikroC PRO for PIC compiler allows you to access individual bits of 8-bit variables by their name or position in the byte:INTCON.B0 = 0; // Clear bit 0 of the INTCON register ADCON0.F5 = 1; // Set bit 5 of the ADCON0 register INTCON.GIE = 0; // Clear Global Interrupt Bit (GIE)
SBIT TYPE
The mikroC PRO for PIC compiler has an sbit data type which provides access to registers, SFRs, variables, etc. In order to declare a bit of a variable, it is sufficient to write:extern sbit Some_Bit; // Some_Bit is defined
char MyVar;
sbit Some_Bit at MyVar.F0; // This is where Some_Bit is declared
...
void main() {
...
}
If you declare an sbit variable in a unit so as to point it to a specific bit of SFR register, it is necessary to use the keyword sfr in declaration, because you are pointing it to the variable defined as sfr variable:
extern sfr sbit Abit; // Abit is precisely defined
...
sbit Abit at PORTB.F0; // Now, Abit is declared
void main() {
...
}
BIT TYPE
The mikroC PRO for PIC compiler provides a bit data type that may be used for variable declarations. It cannot be used for argument lists and function-return values.bit bf; // Valid bit variable bit *ptr; // Invalid bit variable. There are no pointers to bit variables