UM0401

Running the STMPE801 port expander GUI

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2.2

Programming GPIO

The eight GPIOs can be configured as input or output individually and independently of

each other. The status of the GPIOs can be read and are displayed on the "GPIO-functional"

tab of the GUI as shown in Figure 13.

As shown in Figure 14, GPIOs can be configured as outputs by selecting the corresponding

radio button for IN or OUT assignment and clicking the "GPIO Assignment" button. The

output state can be set to High or Low through the corresponding radio button and clicking

on the "Write" button. The resulting state of the GPIOs can be read and displayed by clicking

on the "Read" button.

Like the Read/Write to internal registers, the correct slave device should be chosen before

the GPIO is configured. If the wrong slave device is chosen, errors appear indicating there is

an error reading the GPMR or writing to GPDR registers depending on the function

performed.

Figure 13.

GPIO Input state screen shot