[PHP] I2C, sending a binary byte with fwrite
Hi,
I'm working on a interface between the I2C Bus (Hardware) and PHP - to use
the PHP as webinterface to control an I2C Device.
The bus is mounted as: /dev/i2c8_aux - and works
opening the bus with
$fd=fopen (/dev/i2c8_aux, w (r+) (r+b) (wb))is successfull
setting the address of the slave device (0xB0 (=0x58) and the register
(between 0-15) works
fseek($fd, 0x5801) (accessing register 01)
Now - the things that doesn't work: writting into the register
I'd like to write a value between 0-255 (0x00 and 0xff) e.g into register 1
(the one from above) - (0 = turn left, 128=stop, 255=turn right) I can only
write one (1) byte into the register, and fwrite uses strings.
$data = 128
$rslt = ($fd, $data, 1)
would write 3bytes.
So, what I need is a way to convert any value between 0 and 255 into a
string with one byte, e.g
0xff = (with strlen($data) == 1)
I tried it with:
chr(255) - not successfull
pack("H" and "h", 0xff) - not successfull
decbin(255) - without success
and many more.
Any advice, suggestion, experience? Thanks!
Tobias
[PHP] I2C and PHP
Hi,
I'm working on a interface between the I2C Bus (Hardware) and PHP - to use
the PHP as webinterface to control an I2C Device.
The bus is mounted as: /dev/i2c8_aux - and works
opening the bus with
$fd=fopen (/dev/i2c8_aux, w (r+) (r+b) (wb))is successfull
setting the address of the slave device (0xB0 (=0x58) and the register
(between 0-15) works
fseek($fd, 0x5801) (accessing register 01)
Now - the things that doesn't work: writting into the register
I'd like to write a value between 0-255 (0x00 and 0xff) e.g into register 1
(the one from above) - (0 = turn left, 128=stop, 255=turn right) I can only
write one (1) byte into the register, and fwrite uses strings.
$data = 128
$rslt = ($fd, $data, 1)
would write 3bytes.
So, what I need is a way to convert any value between 0 and 255 into a
string with one byte, e.g
0xff = (with strlen($data) == 1)
I tried it with:
chr(255) - not successfull
pack("H" and "h", 0xff) - not successfull
decbin(255) - without success
And many more variations
Any ideas, suggestions, Thanks!
tobias
[PHP] Passing Values between C App and PHP
Hi, I've recently written an eMail regarding I2C and PHP - since I haven't found a nice solution yet, I'm considering writting the I2C part (opening device, writing, reading,...) in C (that's simple) and to recieve (and returning) the values through PHP and Javascript. E.g. Website (PHP/Javascript) -> set a new motorspeed -> PHP passes the new speed to C Application -> C AP opens and writes the new speed onto the I2C Bus -> Motor executes -> returns ack -> Is this somehow, and not complicated possible? Thanks, Tobias -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Passing Values between C App and PHP
Am 21.06.2009 um 23:31 schrieb Nathan Nobbe: On Sun, Jun 21, 2009 at 3:25 PM, Tobias Krieger > wrote: Hi, I've recently written an eMail regarding I2C and PHP - since I haven't found a nice solution yet, I'm considering writting the I2C part (opening device, writing, reading,...) in C (that's simple) and to recieve (and returning) the values through PHP and Javascript. E.g. Website (PHP/Javascript) -> set a new motorspeed -> PHP passes the new speed to C Application -> C AP opens and writes the new speed onto the I2C Bus -> Motor executes -> returns ack -> Is this somehow, and not complicated possible? if the C program is written such that it can start and stop on every request rather than as a daemon, its as simple as shell_exec(). write your C app to take args over the cli and then pass them in through the call: something of that nature. -nathan This would be a nice and fast solution, but unfortunatelly, it's like that the C programm needs to surveilance the hardware all the time (controlling values,...) hence, it would run more as a "daemon". thx, tobias
