Re: [Botix-devel] HAL for Botix

[Ger A. <in...@ge...>]

Hi wouter,

I've edited your documentation so that it works with DOC++.

Basicly a few issues:

A function documentation starts with /** <- double star
If you use the single star, it will be disregarded by doc++

Only if you've got a long and a short description, you should use the 
memo field. If there is only a memo field, a seperate page for the 
function will not be made.

If there is no parameter or no return, these should not be mentioned.

Thanks!

Greetings,
Ger.

Wouter Houweling schreef:

>Hi all,
>
>Tonight I committed the first version of a HAL for Botix.
>(Botix/Hardware/Hal)
>
>The purpose of the HAL is to provide a controlled layer over the
>hardware, to protect the hardware and ease in debugging. Because the HAL
>knows the purpose of the connected devices and their pins it knows when
>an illegal command is performed: like setting an input pin. This greatly
>reduces errors and creates a safety net for beginners.
>
>Another purpose of the hal is to check and debug the software pin map 
>to the hardware pin map by printing out what the HAL knows about the pin
>usage. It is possible to show runtime the status of the devices & pins.
>
>Last but not least: the functional programming can use symbolic device
>names instead of pin address. This very much increases code readability
>and makes it for easy device programming. (No knowledge required *how*
>the device works, let the hal take care of that.)
>
>Short overview of the hall:
>
>- Class: set of devices.
>- Device: abstract device which is connected to zero or more pins.
>- Port: set of pins used for a device.
>- Pin: actual hardware pin.
>- Driver: small function which contains all logic to use a device. (i.e:
>send a ping for a sonar device)
>
>Hal->|-> Class 'Sensor' |-> Device |-> Driver 'srf04'
>			 | 		 |		  					   |-> Pin A1 Input
> 	    |		 |		  					   |-> Pin A2 Output
> 	    |		 |
> 	    |		 |-> Device	|-> Driver
> 	    |		 			|-> Pin
> 	    |
>     	    |-> Class 'Led' -> etc.
> 	    |
> 	    |-> Ports |-> Pin 1 (owner device 'Sonar1'
> 				  |-> Pin 2 (owner device 'Sonar1'
> 				  |-> Pin 3 (owner device ''
> 
>Drivers do not know which actual pins they use, because there is a 
>device pin map -> actual pin map. Because of this drivers can be very
>generic.
>
>To keep memory footprint low, all strings are pointers back into rom. As
>always with abstraction some cpu overhead is unavoidable. At this moment
>it is unknown what the performance on an actual embedded cpu (AVR) is.
>
>Controlling the hal works like this:
>
>register_class("switches");
>register_class("leds");
>register_class("sonars");
>	
>register_dev("led1", 
>	     find_class("leds"), 	/* class */
>	     1, 			/* number of pins */
>	     (PORT []){1, OUTPUT}, 	/* pin list */
>	     &generic_led);		/* driver */
>
>register_dev("sonar_left" 
>	     find_class("sonars"), 		/* class */
>	     2, 				/* number of pins */
>	     (PORT []){1, OUTPUT, 2 INPUT}, 	/* pin list */
>	     &generic_led);			/* driver */
>
>set_dev("led1", ON);
>int dist = get_dev("sonar1");
>
>A driver looks like this:
>
>float generic_led(int mode) {
>	printf("Led driver called!\n");
>	switch(mode) {
>		case ON: set_pin(1, ON); break;
>		case OFF: set_pin(1, ON); break;
>	}
>}
>
>You get the idea ;-)
>
>At this moment this concept is working when compiling hal_demo.c on a
>pc. (Botix/Hardware/Hal)
>
>The hal should be directly driven by an protocol stack or small virtual
>machine running on the CPU.
>
>One big problem at this time is memory consumption, I will keep trying
>to reduce the memory footprint.
>
>Let met know what you all think of this!
>
>Greetings,
>Wouter
>
>
>
>
>
>
>
>
>
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