I2C_PCF8574_read block
Short summary
Name |
I2C_PCF8574_read |
→POU type |
|
Category |
|
Graphical interface |
|
Available since |
|
Functionality
The block reads the states of inputs from PCF8574 (→I2C port expanders).
For more information on the PCF8574 chip see for example: http://www.nxp.com/documents/data_sheet/PCF8574.pdf (product specification by manufacturer NXP)
Inputs, return value
|
Identifier |
Description |
|
Inputs: |
fd |
DINT |
the handle for the I2C device file opened by the I2C_Open block |
address |
INT |
the I2C address of the PCF8574 (port expander) |
|
Return value: |
– |
ARRAY[0..7] OF BOOL |
returns the states of the pins of the PCF8574 (port expander) |
Input EN and output ENO are available when →calling the block. See "Execution control: EN, ENO" for information on input EN and output ENO.
Example for usage within ST-editor
PROGRAM Test
VAR
handle : DINT := -
1
;
digitals : ARRAY[
0
..
7
] OF BOOL;
END_VAR;
ENO := TRUE;
IF handle <
0
THEN
handle := I2C_open(bus_id :=
1
, ENO => ENO);
ELSIF ENO THEN
digitals := I2C_PCF8574_read(fd := handle, address :=
56
, ENO => ENO);
END_IF;
END_PROGRAM
When creating your application within the ST-editor, enter a call of a block by typing the text as requested by the syntax or use Content Assist.