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, $data, 1)
would write 3bytes.
So, what I need is a way to convert any value between 0 and 255 into a
string with one byte, e.g
0xff = 1111 1111 (with strlen($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
