nanogui: Thread: Button interaction over GPIO

Hello,

I am looking for a way to have some interaction with Nano-X through 
buttons connected via general purpose I/O (GPIO) to an ARM9 board 
running Linux 2.6.15.

By now, I am launching a thread that simply reads all GPIO ports all 
30ms (the code is below). But it does not work well, it lasts a long 
time until Nano-X reacts to the pressing of a key.

I guess it would be the best to use Nano-X's event handling. But in 
order to achieve that, I suppose that I need a driver, don't I?

Any help would be very appreciated

Thanks

raph


/* read ports */
while (1) {
     port = 2;
     result = read(handle[port], &b[port], 1);

     if (b[port] == 0x07) { /* button connected to 2 pressed */
         if (red_button_state == 0) {
             red_button_state = 1;
                 printf("DEBUG: red button switched on\n");
             }
         }
         else {
             if (red_button_state == 1) {
                 printf("DEBUG: red button switched off\n");
                 red_button_state = 0;
             }
         }
         if (result != 1) {
             perror("Can't read byte from port");
             return;
         }
     usleep(READ_CONST * 1000);
}

Raph,

What you need to try using is the PIPEKBD option. Go to the nano-X 
config file and enable
PIPEKBD = Y and rebuild nano-X.

 Look in the docs and you will find out how to use it.

Basicaly, you have a seperate process/therad that reads your GPIO 
keyboard and decides what key was pressed, repeating key, etc and sends 
that info through the pipe according to the nanoX specification. It is 
then read from the main event loop in your app as a key event.
Again see the nano-X docs on about the specifics of creating and what to 
write through the pipe.

tj

Raph HP wrote:

> Hello,
>
> I am looking for a way to have some interaction with Nano-X through 
> buttons connected via general purpose I/O (GPIO) to an ARM9 board 
> running Linux 2.6.15.
>
> By now, I am launching a thread that simply reads all GPIO ports all 
> 30ms (the code is below). But it does not work well, it lasts a long 
> time until Nano-X reacts to the pressing of a key.
>
> I guess it would be the best to use Nano-X's event handling. But in 
> order to achieve that, I suppose that I need a driver, don't I?
>
> Any help would be very appreciated
>
> Thanks
>
> raph
>
>
> /* read ports */
> while (1) {
>     port = 2;
>     result = read(handle[port], &b[port], 1);
>
>     if (b[port] == 0x07) { /* button connected to 2 pressed */
>         if (red_button_state == 0) {
>             red_button_state = 1;
>                 printf("DEBUG: red button switched on\n");
>             }
>         }
>         else {
>             if (red_button_state == 1) {
>                 printf("DEBUG: red button switched off\n");
>                 red_button_state = 0;
>             }
>         }
>         if (result != 1) {
>             perror("Can't read byte from port");
>             return;
>         }
>     usleep(READ_CONST * 1000);
> }
>
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> To unsubscribe, e-mail: ####@####.####
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>
>

Hi raph

You need to develop kernel space keyboard driver which will generate
keypress/release events to the linux input subsystem, you can find
references in ./drivers/input/keyboard 
Then using standard event interface of linux input subsystem you can get
events in userspace using device node /dev/input/event# (evdev.ko need to be
installed for this)
If you are configuring console=tty0 then your STDIN will become installed
keypad and nano-X should work with appropreate configuration
If you are using any other console (generally serial port in most of cases)
then, for nano x you need to add keypad driver which polls events from
/dev/input/event0 and generates events for nano-X

Regards..
Prafulla . .


-----Original Message-----
From: Raph HP ####@####.#### 
Sent: Monday, November 06, 2006 3:08 PM
To: ####@####.####
Subject: [nanogui] Button interaction over GPIO

Hello,

I am looking for a way to have some interaction with Nano-X through buttons
connected via general purpose I/O (GPIO) to an ARM9 board running Linux
2.6.15.

By now, I am launching a thread that simply reads all GPIO ports all 30ms
(the code is below). But it does not work well, it lasts a long time until
Nano-X reacts to the pressing of a key.

I guess it would be the best to use Nano-X's event handling. But in order to
achieve that, I suppose that I need a driver, don't I?

Any help would be very appreciated

Thanks

raph


/* read ports */
while (1) {
     port = 2;
     result = read(handle[port], &b[port], 1);

     if (b[port] == 0x07) { /* button connected to 2 pressed */
         if (red_button_state == 0) {
             red_button_state = 1;
                 printf("DEBUG: red button switched on\n");
             }
         }
         else {
             if (red_button_state == 1) {
                 printf("DEBUG: red button switched off\n");
                 red_button_state = 0;
             }
         }
         if (result != 1) {
             perror("Can't read byte from port");
             return;
         }
     usleep(READ_CONST * 1000);
}

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