nanogui: Button interaction over GPIO
Subject:
RE: [nanogui] Button interaction over GPIO
From:
Prafulla WADASKAR ####@####.####
Date:
9 Nov 2006 03:53:46 +0000
Message-Id: <006501c703b2$903ac0a0$872cc70a@dlh.st.com>
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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