Configuration settings are one of the more confusing topics to someone just getting started with Programming PIC Microcontrollers and often is the hurdle they have to get over to get that first LED to flash. The configuration settings enable the features of the micro. Settings, such as enabling the Debug feature, Low Voltage Programming or setting the Oscillator to internal or external are just some of the options.
They are sometimes called fuses since in older one time programmable parts they were set once and couldn't be changed. But with today's modern flash memory devices, the configuration can be changed every time the part is programmed.
The configuration is really just a set of bits that get set or cleared to enable or disable the feature. These bits are grouped together into a byte or several bytes depending on how many features need to be configured.
They are sometimes called fuses since in older one time programmable parts they were set once and couldn't be changed. But with today's modern flash memory devices, the configuration can be changed every time the part is programmed.
The configuration is really just a set of bits that get set or cleared to enable or disable the feature. These bits are grouped together into a byte or several bytes depending on how many features need to be configured.
A compiler will have a macro to set the configuration and it's usually placed at the top of a software program. Typically it's a line that starts with #config or __config and then followed by the nicknames for each bit setting.
One of the features I like about the Great Cow Basic compiler is the Graphical version that lets you select the part, the oscillator speed and each configuration setting from a drop down menu. Then when you select to build the file it will produce the BASIC and assembly language file with those settings. Shown below is an assembly file __CONFIG line produced by the GCB Graphical compiler.
One of the features I like about the Great Cow Basic compiler is the Graphical version that lets you select the part, the oscillator speed and each configuration setting from a drop down menu. Then when you select to build the file it will produce the BASIC and assembly language file with those settings. Shown below is an assembly file __CONFIG line produced by the GCB Graphical compiler.
This one config line from the assembly file can be used as a reference for any other compiler since most use a similar CONFIG type line, though it will probably need a slight modification to match the compilers syntax.
Microchip's MPLAB X has a similar drop down menu option in the Configuration View. This is very useful for those programming with Microchip's tools. It's under the toolbar menu: Window>PIC Memory Views>Configuration Bits.
Microchip's MPLAB X has a similar drop down menu option in the Configuration View. This is very useful for those programming with Microchip's tools. It's under the toolbar menu: Window>PIC Memory Views>Configuration Bits.
You also have the option to export your choices as a separate config.h file so you can include it at the top of your main.c file for all you C programmers out there. You can get details of all the config settings in the device data sheet under the special features section.
Bottom line is to don't forget to learn and understand the configuration settings for the device you are using and then set them once and kind of forget it. Then you'll be past that hurdle.
Bottom line is to don't forget to learn and understand the configuration settings for the device you are using and then set them once and kind of forget it. Then you'll be past that hurdle.
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