Instrument control package: Difference between revisions
Jump to navigation
Jump to search
→i2c
(→i2c) |
(→i2c) |
||
| Line 372: | Line 372: | ||
In the example case the temperature sensor is connected to the i2c-ch341-usb device, as as sufficient permissions to access the device as a user. | In the example case the temperature sensor is connected to the i2c-ch341-usb device, as as sufficient permissions to access the device as a user. | ||
According to the datasheet, the temperature device uses address 0x40, so create a i2c device using the linux device and address: | |||
<syntaxhighlight lang="octave" style="font-size:13px"> | |||
i2cdev = i2c("/dev/i2c-1", 0x40) | i2cdev = i2c("/dev/i2c-1", 0x40) | ||
</syntaxhighlight> | |||
To read the termaturem register 0xF3 must be addressed and read (2 bytes of data): | To read the termaturem register 0xF3 must be addressed and read (2 bytes of data): | ||
<syntaxhighlight lang="octave" style="font-size:13px"> | |||
TEMP_MEASURE_NOHOLD = hex2dec("F3"); | TEMP_MEASURE_NOHOLD = hex2dec("F3"); | ||
fwrite (i2cdev, uint8([TEMP_MEASURE_NOHOLD])); | fwrite (i2cdev, uint8([TEMP_MEASURE_NOHOLD])); | ||
pause (0.02); | pause (0.02); | ||
data = fread (i2cdev, 3); | data = fread (i2cdev, 3); | ||
</syntaxhighlight> | |||
<syntaxhighlight lang="octave" style="font-size:13px"> | |||
value = uint16(data(1))*256 + uint16(data(2)); | value = uint16(data(1))*256 + uint16(data(2)); | ||
value = bitand (value, hex2dec("FFFC")); | value = bitand (value, hex2dec("FFFC")); | ||
temp_Code = double(value); | temp_Code = double(value); | ||
</syntaxhighlight> | |||
Now convert the temperature to degrees C and display: | Now convert the temperature to degrees C and display: | ||
<syntaxhighlight lang="octave" style="font-size:13px"> | |||
C = (175.72*temp_Code/65536)-46.85; | C = (175.72*temp_Code/65536)-46.85; | ||
printf ("temperature read %f C\n", C); | printf ("temperature read %f C\n", C); | ||
</syntaxhighlight> | |||
== TCP == | == TCP == | ||