Configuring Keil uVision to create .hex file

When you write a program for a microcontroller, you would often want to “dump” or “upload” the code to the hardware to test it. Most of the new development boards such as the Arduino series or the Cypress PS0C series come with their own IDEs which do the work of dumping the code to the development board for you. So you don’t even need to know the whole process.

But when it comes to the legacy microcontrollers, such as the good old 8051 series, you will have to manually dump something called a “.hex” file onto the development board. Depending on the manufacturer of the IC, there are different tools to dump the .hex file to the controller. For this, you first need to generate or create the .hex file.

A .hex file is most often compulsorily created for every microcontroller. But different IDEs handle these file differently. For example, the Arduino IDE will not even tell you that a .hex file has been created. Anyway, when you are writing a program for a microcontoller on Keil uVision, and you need the .hex file to dump it to the IC, you need to explicitly tell the tool to create the .hex file for you. By default, this feature is disabled. To configure Keil uVision to create a .hex file for every build, follow these steps:

1. Before building the program, click the “Flash” menu on the menu bar and  select the option, “Configure Flash Tools…”

2. The “Options for Target…” window will be displayed. In this window, select the “Device” tab. You will see a big list of controllers to the left of the window. Make sure that you have selected the correct controller. In this example, it is the Atmel AT89C51.

3. Next, select the “Target” tab and enter the exact Xtal frequency in MHz. In this example, it is 16 MHz.

4. Now, go to the “Output” tab and check the “Create HEX file” checkbox. Also, you can change the name of the executable which is created.

That’s it. You are done configuring the tool to create .hex file. Now you build the project. Once you have successfully built the project, check  your project folder and you should have the .hex file created there, as you can see in the screenshot below.

If you want to get started right away, below is a sample code which you can copy to a new file in uVision, build it, and create the .hex file. The process described here changes for every IDE. In my experience, working with .hex file in the Arduino IDE was a bit tricky, only till I figured it out. I will be writing another post very soon on how to configure the Arduino IDE to create the .hex file at  a defined path.

/* AT89C51 TImer function sample. */
/* By Sunny */
/* Vcc To Ground (vcctoground.com) */

#include<reg51.h>

sbit LED1 = P3^0;
sbit LED2 = P3^1;

unsigned int count = 0;

void delay()
{
	TMOD = 0x01;
	TL0 = 0X00;
	TH0 = 0X00;

	TR0 = 1;

	while(TF0 == 0);

	TR0 = 0;
	TF0 = 0;
}

void main()
{
	unsigned int i = 0;
	while(1)
	{
		if(count & 0x02)
			LED2 = 1;
		else
			LED2 = 0;

		LED1 = 1;
		
		for(i=0; i<10; i++)
			delay();

		LED1 = 0;
		
		for(i=0; i<10; i++)
			delay();

		count++;
	}
}