interface definition

What's an interface? because there are two definition. One a physic interface which it's a physic connection between two electronic or hardware device. And there is an other interface, the logic interface.
So, Can we say that the driver is the "connection" between the physic and the logic interface?

Hi,

Not 100% certain of your last sentence, because of the word "driver".

I'd say that interface means anything that connects two or more things together.

edaboard is the interface between users.

Eyes are interface between senses/brain and visible world.

A comparator is an interface between e.g. a sensor and a logic device.

L293 (enable pin) could be seen as an interface between hardware and a "logic" signal.

"Inter" = between
"Face" = that part of something that passes/receives information to/from outside an entity.

So basically, it's the junction between two things, which may or may not be dissimilar.

Brian.

Yes yes I understood the definition of interface as a physical conection between components. Take a look to the term "driver", it's a software or electronic circuit which control a part of a dedicated hardware giving a relationship between the general code (which decode and execute the processor) and the code which the dedicated hardware can decode-execute. So in this definition of driver there must be a physical interface and a logic interface (because in all case the driver gives to the processor a "differetn vision" of the hardware part.
Example, when there is an instruction of read a hard disck's data. In the microprocessor there is an interrupt or a call to a memory location which has the biginning of the driver code and of course the chipset gives the logic and the physical interface between the micro and the hard disk. The micro just see the hard disk as a I/O port

other example, the DMA gives a maped memory which do not correspond whit the physical memory, so it's a logic interface and gives an physical interface like a PCI bus or ISA, so there must be a driver which decode and execute the micro call to read or write memory and decode the memory map to the physical map.

I think the confusion is with the term 'logic interface' which you are assuming is an 'intelligent' connection that allows conversation between different devices. For the most part, a logic interface is a reference to logic levels, the digital high and low voltages representing a '1' or a '0'.

A driver is normally the name we give to a device that enforces a voltage or current condition on the other device but not neccessarily at logic levels. For example an RS232 'driver' would be a circuit producing +12V and -12V as it's output voltage. It could also be an analog signal such as "driving a loudspeaker".

There is another term "device driver" which may be adding to the confusion. That is a program that typically converts high level instructions into ones used by an external device such as a video card, sound card or printer. In that case it is entirely software and would probably be controlling a harware interface to communicate with that device.

Brian.

Ah, thanks. So a driver is not the same that a device driver which this last one is a software. I wanted to say a device driver so.

If we look wikipedia https://en.wikipedia.org/wiki/Device_driver

There says that device driver provides a software interface to hardware devices, and of course the hardwares devices are conected by the physic interface. So, by that. Can I say that the device driver is the relationsheep between the physic and software interface?

That is correct. The term "device driver" really came about when PC operating systems got more complicated and here became a need for standardizing the method to 'talk' to peripherals. In old days, each program had it's own software to communicate with the hardware, even each model of hard disk needed it's own software and hardware to make it work. When multi-purpose operating systems started appearing, there was a need for a universal way that any application could communicate with any peripheral and the 'device driver' was born. Basically, it is written specifically for the peripheral device but has a common software language that lets any application use it.

For example, take a printer device driver - it would be written by the software people at the printer manufacturer to suit the requirements of the printer mechanism but it would have a common communication method that allowed any program to use it, whether it be a photograph, document or spreadsheet. Without the device driver, every application program would have to cater for every different printer the user might use.

Brian.