Assoc. Prof. Wiroon Sriborrirux, Founder of Advance Innovation Center (AIC) and Bangsaen Design House (BDH), Electrical Engineering Department, Faculty of Engineering, Burapha University
Lab Objective:
In this lab, participants will interface with the Infineon PSoC 6 microcontroller's CAPSENSE hardware to implement capacitive sensing for both buttons and sliders. By harnessing the CAPSENSE capabilities, participants will design touch-based interfaces that react to user inputs. Additionally, they will utilize the Capsense Tuner tool to monitor, calibrate, and fine-tune the capacitive sensing parameters, ensuring optimal responsiveness and accuracy. This hands-on exercise aims to provide participants with a comprehensive understanding of capacitive touch technologies, emphasizing the importance of tuning and calibration in delivering a seamless user experience.
The code example features a 5-segment CAPSENSE™ slider and two CAPSENSE™ buttons. Button 0 turns the LED ON, button 1 turns the LED OFF, and the slider controls the brightness of the LED. The code example also demonstrates monitoring CAPSENSE™ data using the CAPSENSE™ tuner GUI tool. This project uses the CAPSENSE™ Middleware Library.
main.c
#include"cybsp.h"#include"cyhal.h"#include"cycfg.h"#include"cycfg_capsense.h"#include"led.h"#include"cy_retarget_io.h"/******************************************************************************** Macros*******************************************************************************/#defineCAPSENSE_INTR_PRIORITY (7u)#defineEZI2C_INTR_PRIORITY (6u) /* EZI2C interrupt priority must be * higher than CapSense interrupt *//******************************************************************************** Function Prototypes*******************************************************************************/staticuint32_tinitialize_capsense(void);staticvoidprocess_touch(void);staticvoidinitialize_capsense_tuner(void);staticvoidcapsense_isr(void);staticvoidcapsense_callback();voidhandle_error(void);/******************************************************************************** Global Variables*******************************************************************************/cy_stc_scb_ezi2c_context_t ezi2c_context;cyhal_ezi2c_t sEzI2C;cyhal_ezi2c_slave_cfg_t sEzI2C_sub_cfg;cyhal_ezi2c_cfg_t sEzI2C_cfg;volatilebool capsense_scan_complete =false;/******************************************************************************** Function Name: handle_error********************************************************************************* Summary:* User defined error handling function** Parameters:* void** Return:* void********************************************************************************/voidhandle_error(void){ /* Disable all interrupts. */__disable_irq();CY_ASSERT(0);}/******************************************************************************** Function Name: main********************************************************************************* Summary:* System entrance point. This function performs* - initial setup of device* - initialize CapSense* - initialize tuner communication* - scan touch input continuously and update the LED accordingly.** Return:* int********************************************************************************/intmain(void){cy_rslt_t result;#ifdefined (CY_DEVICE_SECURE)cyhal_wdt_t wdt_obj; /* Clear watchdog timer so that it doesn't trigger a reset */ result =cyhal_wdt_init(&wdt_obj, cyhal_wdt_get_max_timeout_ms());CY_ASSERT(CY_RSLT_SUCCESS == result);cyhal_wdt_free(&wdt_obj);#endif /* Initialize the device and board peripherals */ result =cybsp_init(); /* Board init failed. Stop program execution */if (result != CY_RSLT_SUCCESS) {CY_ASSERT(0); } /* Enable global interrupts */__enable_irq(); /* Initialize retarget-io to use the debug UART port */ result =cy_retarget_io_init(CYBSP_DEBUG_UART_TX, CYBSP_DEBUG_UART_RX, CY_RETARGET_IO_BAUDRATE); /* retarget-io init failed. Stop program execution */if (result != CY_RSLT_SUCCESS) {CY_ASSERT(0); } /* \x1b[2J\x1b[;H - ANSI ESC sequence for clear screen */printf("\x1b[2J\x1b[;H");printf("**********************************************************\r\n");printf("PSoC 6 MCU: CAPSENSE buttons and slider\r\n");printf("**********************************************************\r\n");initialize_led();initialize_capsense_tuner(); result =initialize_capsense();if (CYRET_SUCCESS != result) { /* Halt the CPU if CapSense initialization failed */CY_ASSERT(0); } /* Initiate first scan */Cy_CapSense_ScanAllWidgets(&cy_capsense_context);for (;;) {if (capsense_scan_complete) { /* Process all widgets */Cy_CapSense_ProcessAllWidgets(&cy_capsense_context); /* Process touch input */process_touch(); /* Establishes synchronized operation between the CapSense * middleware and the CapSense Tuner tool. */Cy_CapSense_RunTuner(&cy_capsense_context); /* Initiate next scan */Cy_CapSense_ScanAllWidgets(&cy_capsense_context); capsense_scan_complete =false; } }}/******************************************************************************** Function Name: process_touch********************************************************************************* Summary:* Gets the details of touch position detected, processes the touch input* and updates the LED status.********************************************************************************/staticvoidprocess_touch(void){uint32_t button0_status;uint32_t button1_status;cy_stc_capsense_touch_t*slider_touch_info;uint16_t slider_pos;uint8_t slider_touch_status;bool led_update_req =false;staticuint32_t button0_status_prev;staticuint32_t button1_status_prev;staticuint16_t slider_pos_prev;staticled_data_t led_data = {LED_ON, LED_MAX_BRIGHTNESS}; /* Get button 0 status */ button0_status =Cy_CapSense_IsSensorActive( CY_CAPSENSE_BUTTON0_WDGT_ID, CY_CAPSENSE_BUTTON0_SNS0_ID,&cy_capsense_context); /* Get button 1 status */ button1_status =Cy_CapSense_IsSensorActive( CY_CAPSENSE_BUTTON1_WDGT_ID, CY_CAPSENSE_BUTTON1_SNS0_ID,&cy_capsense_context); /* Get slider status */ slider_touch_info =Cy_CapSense_GetTouchInfo( CY_CAPSENSE_LINEARSLIDER0_WDGT_ID,&cy_capsense_context); slider_touch_status =slider_touch_info->numPosition; slider_pos =slider_touch_info->ptrPosition->x; /* Detect new touch on Button0 */if ((0u!= button0_status) && (0u== button0_status_prev)) {led_data.state = LED_ON; led_update_req =true; } /* Detect new touch on Button1 */if ((0u!= button1_status) && (0u== button1_status_prev)) {led_data.state = LED_OFF; led_update_req =true; } /* Detect the new touch on slider */if ((0!= slider_touch_status) && (slider_pos != slider_pos_prev)) {led_data.brightness = (slider_pos *100)/cy_capsense_context.ptrWdConfig[CY_CAPSENSE_LINEARSLIDER0_WDGT_ID].xResolution; led_update_req =true; } /* Update the LED state if requested */if (led_update_req) {update_led_state(&led_data); } /* Update previous touch status */ button0_status_prev = button0_status; button1_status_prev = button1_status; slider_pos_prev = slider_pos;}/******************************************************************************** Function Name: initialize_capsense********************************************************************************* Summary:* This function initializes the CapSense and configure the CapSense* interrupt.********************************************************************************/staticuint32_tinitialize_capsense(void){uint32_t status = CYRET_SUCCESS; /* CapSense interrupt configuration parameters */staticconstcy_stc_sysint_t capSense_intr_config = { .intrSrc = csd_interrupt_IRQn, .intrPriority = CAPSENSE_INTR_PRIORITY, }; /* Capture the CSD HW block and initialize it to the default state. */ status =Cy_CapSense_Init(&cy_capsense_context);if (CYRET_SUCCESS != status) {return status; } /* Initialize CapSense interrupt */cyhal_system_set_isr(csd_interrupt_IRQn, csd_interrupt_IRQn, CAPSENSE_INTR_PRIORITY,&capsense_isr);NVIC_ClearPendingIRQ(capSense_intr_config.intrSrc);NVIC_EnableIRQ(capSense_intr_config.intrSrc); /* Initialize the CapSense firmware modules. */ status =Cy_CapSense_Enable(&cy_capsense_context);if (CYRET_SUCCESS != status) {return status; } /* Assign a callback function to indicate end of CapSense scan. */ status =Cy_CapSense_RegisterCallback(CY_CAPSENSE_END_OF_SCAN_E, capsense_callback,&cy_capsense_context);if (CYRET_SUCCESS != status) {return status; }return status;}/******************************************************************************** Function Name: capsense_isr********************************************************************************* Summary:* Wrapper function for handling interrupts from CapSense block.********************************************************************************/staticvoidcapsense_isr(void){Cy_CapSense_InterruptHandler(CYBSP_CSD_HW,&cy_capsense_context);}/******************************************************************************** Function Name: capsense_callback()********************************************************************************* Summary:* This function sets a flag to indicate end of a CapSense scan.** Parameters:* cy_stc_active_scan_sns_t* : pointer to active sensor details.********************************************************************************/voidcapsense_callback(cy_stc_active_scan_sns_t* ptrActiveScan){ capsense_scan_complete =true;}/******************************************************************************** Function Name: initialize_capsense_tuner********************************************************************************* Summary:* Initializes interface between Tuner GUI and PSoC 6 MCU.********************************************************************************/staticvoidinitialize_capsense_tuner(void){cy_rslt_t result; /* Configure Capsense Tuner as EzI2C Slave */sEzI2C_sub_cfg.buf = (uint8 *)&cy_capsense_tuner;sEzI2C_sub_cfg.buf_rw_boundary =sizeof(cy_capsense_tuner);sEzI2C_sub_cfg.buf_size =sizeof(cy_capsense_tuner);sEzI2C_sub_cfg.slave_address =8U;sEzI2C_cfg.data_rate = CYHAL_EZI2C_DATA_RATE_400KHZ;sEzI2C_cfg.enable_wake_from_sleep =false;sEzI2C_cfg.slave1_cfg = sEzI2C_sub_cfg;sEzI2C_cfg.sub_address_size = CYHAL_EZI2C_SUB_ADDR16_BITS;sEzI2C_cfg.two_addresses =false; result =cyhal_ezi2c_init(&sEzI2C, CYBSP_I2C_SDA, CYBSP_I2C_SCL,NULL,&sEzI2C_cfg);if (result != CY_RSLT_SUCCESS) {handle_error(); }}
Build Application
Launches Application
Result
Open CAPSENSE Tuner
🎉 Congratulations! You can now complete this lab
Supported toolchains (make variable 'TOOLCHAIN')
GNU Arm® embedded compiler v10.3.1 (GCC_ARM) - Default value of TOOLCHAIN
