Software description

AN3397

16/24

Doc ID 018809 Rev 1

General purpose input/output (GPIO)

The GPIO ports C and E are interfaced with a user push-button and light-emitting diodes

(LEDs). The GPIO peripheral is configured as follows:

●

PC1 set as input floating pin with interrupt (the user push-button)

●

PC7 and PE7 set as output push-pull pin (LED4 and LED3 respectively)

●

When the user push-button is pressed, an interrupt with interrupt sensitivity set to

falling edge and low level is generated on PC1.

3.2

Application software flowchart

3.2.1

Main TS application routine flowchart

The main TS application routine (Figure 5) initializes all the peripherals using the settings

listed in Section 3.1: STM8L peripherals used by the application.

After initialization, interrupts are enabled and the application operation mode is tested.

If #define ADVANCED_MODE is commented in the main.c file, the application automatically

switches to Normal operating mode using the typical V90 value and the default Avg_slope

(Section 2.4.2: Operating modes).

On the other hand, in Advanced operating mode, the factory calibration data point is tested

for validity. If the factory calibration point does not exist or is not within the tolerance defined

in the datasheet, the application automatically switches back to Normal mode. If the factory

calibration point does exist, the application tests whether or not the user calibration point

has already been processed.

If the user calibration point has been processed, the application goes directly to the infinite

loop for temperature acquisition.

If the user calibration point has not been processed, the application uses this data point to

accurately calculate the sensor characteristic slope before going into the main infinite loop.