Device drivers, also known as hardware drivers or just drivers, are files used by hardware devices to communicate with the operating system of a device. This could be a printer talking to a personal computer or a speaker connected to an information appliance.
Without drivers, we wouldn’t be able to use peripheral devices like printers, speakers, keyboards and secondary screens. Hardware and software is always evolving, and that is why device driver development is an ongoing process.
Step 1: Know Your Hardware
In general, you can do this by reading the schematics for the hardware and the data sheet for the driver. Capture details like supported operations, the type of bus, and the bus address.
If you’re dealing with a new type of hardware, expect the documentation to fall short. This means you’ll learn a lot that isn’t covered by the documentation, and you’ll need to do more testing than would be required with established hardware.
Step 2: Talk to the Hardware
This is only possible if you have a working version of the hardware, even if it is a prototype. Start writing the kernel mode driver. Driver development documentation can help in this regard.
The first functions to be developed are the load and unload function. These functions are invoked when the operating system starts and shuts down. The load/unload function will look for the device if it is plugged. And you can’t do something like initialize it if the computer or phone can’t recognize it.
Step 3: Initialize the Hardware
When the device can detect the hardware, the next step is to initialize it. The type of initialization will depend on the type of hardware. This could be anything from writing to the device register to communicating on a long-term basis using proprietary command protocols.
Step 4: Control the Hardware
Controlling the hardware is only possible if you can initialize it and communicate with it. The control process depends on the device. Will it simply relay data such as music from a smartphone to the speaker? Or will you be continually send data to the device as well as instructions such as telling it to print black and white on one side of paper followed by a double-sided print in color?
The device driver will turn data on settings like playing speed and fast-forward input via the computer or smart phone into commands for the device.
Step 5: Begin Data Communication with the Hardware
Many devices need to deal with some type of data. It may be network packets, audio or video or all of the above. Once the device is initialized, you’re able to send the steady stream of data as required. One example would be a smart speaker that plays audio from the internet sent by the PC to the smart speaker.
Or your 3D printer may accept files downloaded from the internet, edited on the computer and then sent to the computer. The user on the computer will get information on the status of the print job and notice of errors. The driver should be able to handle interruptions in communication, too.
Step 6: Control the Data Communication
You need to manage data communication in a number of situations. Prevent a peripheral device from sending too many of the same error message when there is a problem. Send a stop command when the audio stream is done when there is buffer overflow or even a major problem with the sound quality.
Step 7: Test the Driver and Debug It
Testing is a key aspect of Windows driver development. Test the device to make sure it is recognized and initialized. Run functional tests to make sure it works as expected. You may need to set the clock or change the registers. Or you may need to fix hardware issues such as loose USB plugs and incompatible data-power cables.
Test the device driver on a variety of versions of the operating system to verify that it is forward and backward compatible. Once the driver works, you can register it.
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