STMPE610 - Problem with Touch Detection

[epetrou]

Posted on May 22, 2013 at 16:47

Hi Forum users,

I try to bring in my project all the advantages that a TFT Display with touchscreen promises. The touchscreen controller STMPE610 with the Displaytech's TFT Display, DT028ATFT-TS, is used but unfortunately till now I cannot make it work.The Initialisation commands are sent with I2C and it seems that works fine. According to the attached schematic ''TS-Controller_Circuit.JPG'', the IN2 and IN3 are not used and I connected them to the GND with a 10k resistor in between. The capacitors connected to the signal lines TFT_YU, TFT_YD, TFT_XR and TFT_XL are not 2pF but 2.2nF 0603. The interrupt signal TS_INT is connected to an MCU input (R8, pull-up resistor). Now, getting to the point ... I have measured the following voltages with or without touching the surface  Vio = 3.28V  V_XL or V_X- = 3.27V  V_XR or V_X+ = 0V  V_YU or V_Y+ = 0V  V_YD or V_Y- = 0V and no interrupt is generated. What seems the problem? Probably is my misunderstanding of the controller, so pls could you tell me where I've got it all wrong??? Thanks a lot all of you, in advance!!! P.S. This is the initialisation code void STMPE610_Init(void) {     __delay_cycles(1000);          //STMPE610_Write(SYS_CTRL2, 0x0F);     // Disable TSC and ADC Blocks     //__delay_cycles(10);      //    STMPE610_Write(TSC_CTRL, 0x43);     // Enable Touchscreen, 32 points tracking index, X, Y mode //    __delay_cycles(10); //    STMPE610_Write(SYS_CTRL1, 0x02);    // Reset Device //    __delay_cycles(100000);              STMPE610_Write(SYS_CTRL2, 0x0C);     // Enable TSC and ADC Blocks     __delay_cycles(10);     STMPE610_Write(INT_EN, 0x01);         // TOUCH_DETECT-Interrupt are enabled     __delay_cycles(10);     STMPE610_Write(ADC_CTRL1, 0x49);     // 80 clock cycles for ADC conversion, 12-bit ADC and internal ref     __delay_cycles(10000);               // delay 2ms     STMPE610_Write(ADC_CTRL2, 0x01);     // ADC Clock = 3.25 MHz     __delay_cycles(10);     STMPE610_Write(GPIO_AF, 0x00);     __delay_cycles(10);     STMPE610_Write(TSC_CFG, 0x9A);         // Average Control: 4 samples                                          // Touch detect delay: 500us                                          // Panel driver settling time: 500us     __delay_cycles(10);     STMPE610_Write(FIFO_TH, 0x01);         // Not zero value     __delay_cycles(10);     STMPE610_Write(FIFO_STA, 0x01);         // Clear the FIFO Memory Content     __delay_cycles(10);     STMPE610_Write(FIFO_STA, 0x00);         // FIFO back to operation mode     __delay_cycles(10);     STMPE610_Write(TSC_FRACT_XYZ, 0x07);// Data Format for Z-Value     __delay_cycles(10);     STMPE610_Write(TSC_I_DRIVE, 0x01);    // Choose 20mA driving channel     __delay_cycles(10);     STMPE610_Write(TSC_CTRL, 0x03);     // Enable Device, No tracking index, X, Y, Z mode     __delay_cycles(10);     STMPE610_Write(INT_STA, 0xFF);        // Clear all interrupt status     __delay_cycles(10);     STMPE610_Write(INT_CTRL, 0x03);     // Enable the interrupts     __delay_cycles(10);          // define initial Touch Window     /*STMPE610_Write(WDW_TR_X, 0x0FFF);    // Top Right X     __delay_cycles(10);     STMPE610_Write(WDW_TR_Y, 0x0FFF);   // Top Right Y     __delay_cycles(10);     STMPE610_Write(WDW_BL_X, 0x0000);    // Bottom Left X     __delay_cycles(10);     STMPE610_Write(WDW_BL_Y, 0x0000);   // Bottom Left Y     */ }

[epetrou]

Posted on May 24, 2013 at 08:40

Hi all,

the problem is solved. A pin of the FPC connector was not correctly soldered. The circuit works with 2.2nF or 2pF capacitors. This is the initialisation code that I used void STMPE610_Init(void) { __delay_cycles(1000); STMPE610_Write(SYS_CTRL2, 0x0C); // Enable TSC and ADC Blocks __delay_cycles(10); STMPE610_Write(INT_EN, 0x01); // TOUCH_DETECT-Interrupt are enabled __delay_cycles(10); STMPE610_Write(ADC_CTRL1, 0x49); // 80 clock cycles for ADC conversion, 12-bit ADC and internal ref __delay_cycles(10000); // delay 2ms STMPE610_Write(ADC_CTRL2, 0x01); // ADC Clock = 3.25 MHz __delay_cycles(10); STMPE610_Write(GPIO_AF, 0x00); __delay_cycles(10); STMPE610_Write(TSC_CFG, 0x9A); // Average Control: 4 samples // Touch detect delay: 500us // Panel driver settling time: 500us __delay_cycles(10); STMPE610_Write(FIFO_TH, 0x01); // Not zero value __delay_cycles(10); STMPE610_Write(FIFO_STA, 0x01); // Clear the FIFO Memory Content __delay_cycles(10); STMPE610_Write(FIFO_STA, 0x00); // FIFO back to operation mode __delay_cycles(10); STMPE610_Write(TSC_FRACT_XYZ, 0x07);// Data Format for Z-Value __delay_cycles(10); STMPE610_Write(TSC_I_DRIVE, 0x00); // Choose 20mA driving channel __delay_cycles(10); STMPE610_Write(TSC_CTRL, 0x03); // Enable Device, No tracking index, X, Y, Z mode __delay_cycles(10); STMPE610_Write(INT_STA, 0xFF); // Clear all interrupt status __delay_cycles(10); STMPE610_Write(INT_CTRL, 0x03); // Enable the interrupts __delay_cycles(10); // define initial Touch Window STMPE610_Write(WDW_TR_X, 0x0FFF); // Top Right X __delay_cycles(10); STMPE610_Write(WDW_TR_Y, 0x0FFF); // Top Right Y __delay_cycles(10); STMPE610_Write(WDW_BL_X, 0x0000); // Bottom Left X __delay_cycles(10); STMPE610_Write(WDW_BL_Y, 0x0000); // Bottom Left Y } Have a nice day!!!