[SOLVED] Touchscreen Controller STMPE610, TFT DISPLAY DT028ATFT-TS_Problem-No touch detection!

[strape81]

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, are 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, which is totally strange and I feel really uncomfortable about them...
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, of course, no interrupt is generated. What seems to be 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, 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 50mA 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
*/
}

 

[strape81]

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!!!