//*****************************************************************************
//
//! Handles the ADC interrupt for the touch screen.
//!
//! This function is called when the ADC sequence that samples the touch screen
//! has completed its acquisition. The touch screen state machine is advanced
//! and the acquired ADC sample is processed appropriately.
//!
//! It is the responsibility of the application using the touch screen driver
//! to ensure that this function is installed in the interrupt vector table for
//! the ADC3 interrupt.
//!
//! \return None.
//
//*****************************************************************************
void
TouchScreenIntHandler(void)
{
//
// Clear the ADC sample sequence interrupt.
//
HWREG(ADC0_BASE + ADC_O_ISC) = 1 << 3;
//
// Determine what to do based on the current state of the state machine.
//
switch(g_ulTSState)
{
//
// The new sample is an X axis sample that should be discarded.
//
case TS_STATE_SKIP_X:
{
//
// Read and throw away the ADC sample.
//
HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// Set the analog mode select for the YP pin.
//
HWREG(TS_P_BASE + GPIO_O_AMSEL) =
HWREG(TS_P_BASE + GPIO_O_AMSEL) | TS_YP_PIN;
//
// Configure the Y axis touch layer pins as inputs.
//
HWREG(TS_P_BASE + GPIO_O_DIR) =
HWREG(TS_P_BASE + GPIO_O_DIR) & ~TS_YP_PIN;
if(g_eDaughterType == DAUGHTER_SRAM_FLASH)
{
HWREGB(LCD_CONTROL_SET_REG) = LCD_CONTROL_YN;
}
else if(g_eDaughterType == DAUGHTER_FPGA)
{
HWREGH(LCD_FPGA_CONTROL_SET_REG) = LCD_CONTROL_YN;
}
else
{
//
// Default case with no daughter, SDRAM board or any other
// daughter which doesn't mess with the touchscreen interface.
//
HWREG(TS_N_BASE + GPIO_O_DIR) =
HWREG(TS_N_BASE + GPIO_O_DIR) & ~TS_YN_PIN;
}
//
// The next sample will be a valid X axis sample.
//
g_ulTSState = TS_STATE_READ_X;
//
// This state has been handled.
//
break;
}
//
// The new sample is an X axis sample that should be processed.
//
case TS_STATE_READ_X:
{
//
// Read the raw ADC sample.
//
g_sTouchX = HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// Clear the analog mode select for the YP pin.
//
HWREG(TS_P_BASE + GPIO_O_AMSEL) =
HWREG(TS_P_BASE + GPIO_O_AMSEL) & ~TS_YP_PIN;
//
// Configure the X and Y axis touch layers as outputs.
//
HWREG(TS_P_BASE + GPIO_O_DIR) =
HWREG(TS_P_BASE + GPIO_O_DIR) | TS_XP_PIN | TS_YP_PIN;
if((g_eDaughterType != DAUGHTER_SRAM_FLASH) &&
(g_eDaughterType != DAUGHTER_FPGA))
{
HWREG(TS_N_BASE + GPIO_O_DIR) =
HWREG(TS_N_BASE + GPIO_O_DIR) | TS_XN_PIN | TS_YN_PIN;
}
//
// Drive the positive side of the Y axis touch layer with VDD and
// the negative side with GND. Also, drive both sides of the X
// axis layer with GND to discharge any residual voltage (so that
// a no-touch condition can be properly detected).
//
if(g_eDaughterType == DAUGHTER_SRAM_FLASH)
{
HWREGB(LCD_CONTROL_CLR_REG) = LCD_CONTROL_XN | LCD_CONTROL_YN;
}
else if(g_eDaughterType == DAUGHTER_FPGA)
{
HWREGH(LCD_FPGA_CONTROL_CLR_REG) = (LCD_CONTROL_XN |
LCD_CONTROL_YN);
}
else
{
//
// Default case - any daughter which doesn't muck with the
// touchscreen signals.
//
HWREG(TS_N_BASE + GPIO_O_DATA +
((TS_XN_PIN | TS_YN_PIN) << 2)) = 0;
}
HWREG(TS_P_BASE + GPIO_O_DATA + ((TS_XP_PIN | TS_YP_PIN) << 2)) =
TS_YP_PIN;
//
// Configure the sample sequence to capture the X axis value.
//
HWREG(ADC0_BASE + ADC_O_SSMUX3) = ADC_CTL_CH_XP;
//
// The next sample will be an invalid Y axis sample.
//
g_ulTSState = TS_STATE_SKIP_Y;
//
// This state has been handled.
//
break;
}
//
// The new sample is a Y axis sample that should be discarded.
//
case TS_STATE_SKIP_Y:
{
//
// Read and throw away the ADC sample.
//
HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// Set the analog mode select for the XP pin.
//
HWREG(TS_P_BASE + GPIO_O_AMSEL) =
HWREG(TS_P_BASE + GPIO_O_AMSEL) | TS_XP_PIN;
//
// Configure the X axis touch layer pins as inputs.
//
HWREG(TS_P_BASE + GPIO_O_DIR) =
HWREG(TS_P_BASE + GPIO_O_DIR) & ~TS_XP_PIN;
if(g_eDaughterType == DAUGHTER_SRAM_FLASH)
{
HWREGB(LCD_CONTROL_SET_REG) = LCD_CONTROL_XN;
}
else if(g_eDaughterType == DAUGHTER_FPGA)
{
HWREGH(LCD_FPGA_CONTROL_SET_REG) = LCD_CONTROL_XN;
}
else
{
//
// Default case - any daughter which doesn't muck with the
// touchscreen signals.
//
HWREG(TS_N_BASE + GPIO_O_DIR) =
HWREG(TS_N_BASE + GPIO_O_DIR) & ~TS_XN_PIN;
}
//
// The next sample will be a valid Y axis sample.
//
g_ulTSState = TS_STATE_READ_Y;
//
// This state has been handled.
//
break;
}
//
// The new sample is a Y axis sample that should be processed.
//
case TS_STATE_READ_Y:
{
//
// Read the raw ADC sample.
//
g_sTouchY = HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// The next configuration is the same as the initial configuration.
// Therefore, fall through into the initialization state to avoid
// duplicating the code.
//
}
//
// The state machine is in its initial state
//
case TS_STATE_INIT:
{
//
// Clear the analog mode select for the XP pin.
//
HWREG(TS_P_BASE + GPIO_O_AMSEL) =
HWREG(TS_P_BASE + GPIO_O_AMSEL) & ~TS_XP_PIN;
//
// Configure the X and Y axis touch layers as outputs.
//
HWREG(TS_P_BASE + GPIO_O_DIR) =
HWREG(TS_P_BASE + GPIO_O_DIR) | TS_XP_PIN | TS_YP_PIN;
if((g_eDaughterType != DAUGHTER_SRAM_FLASH) &&
(g_eDaughterType != DAUGHTER_FPGA))
{
HWREG(TS_N_BASE + GPIO_O_DIR) =
HWREG(TS_N_BASE + GPIO_O_DIR) | TS_XN_PIN | TS_YN_PIN;
}
//
// Drive one side of the X axis touch layer with VDD and the other
// with GND. Also, drive both sides of the Y axis layer with GND
// to discharge any residual voltage (so that a no-touch condition
// can be properly detected).
//
HWREG(TS_P_BASE + GPIO_O_DATA + ((TS_XP_PIN | TS_YP_PIN) << 2)) =
TS_XP_PIN;
if(g_eDaughterType == DAUGHTER_SRAM_FLASH)
{
HWREGB(LCD_CONTROL_CLR_REG) = LCD_CONTROL_XN | LCD_CONTROL_YN;
}
else if(g_eDaughterType == DAUGHTER_FPGA)
{
HWREGH(LCD_FPGA_CONTROL_CLR_REG) = (LCD_CONTROL_XN |
LCD_CONTROL_YN);
}
else
{
//
// Default case - any daughter which does not muck with the
// touchscreen signals.
//
HWREG(TS_N_BASE + GPIO_O_DATA +
((TS_XN_PIN | TS_YN_PIN) << 2)) = 0;
}
//
// Configure the sample sequence to capture the Y axis value.
//
HWREG(ADC0_BASE + ADC_O_SSMUX3) = ADC_CTL_CH_YP;
//
// If this is the valid Y sample state, then there is a new X/Y
// sample pair. In that case, run the touch screen debouncer.
//
if(g_ulTSState == TS_STATE_READ_Y)
{
TouchScreenDebouncer();
}
//
// The next sample will be an invalid X axis sample.
//
g_ulTSState = TS_STATE_SKIP_X;
//
// This state has been handled.
//
break;
}
}
}
//*****************************************************************************
//
//! Handles the ADC interrupt for the touch screen.
//!
//! This function is called when the ADC sequence that samples the touch screen
//! has completed its acquisition. The touch screen state machine is advanced
//! and the acquired ADC sample is processed appropriately.
//!
//! It is the responsibility of the application using the touch screen driver
//! to ensure that this function is installed in the interrupt vector table for
//! the ADC0 samples sequencer 3 interrupt.
//!
//! \return None.
//
//*****************************************************************************
void
TouchScreenIntHandler(void)
{
//
// Clear the ADC sample sequence interrupt.
//
HWREG(ADC0_BASE + ADC_O_ISC) = ADC_ISC_IN3;
//
// Determine what to do based on the current state of the state machine.
//
switch(g_ui32TSState) {
//
// The new sample is an X axis sample that should be discarded.
//
case TS_STATE_SKIP_X: {
//
// Read and throw away the ADC sample.
//
HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// Set the analog mode select for the YP pin.
//
HWREG(TS_YP_BASE + GPIO_O_AMSEL) |= TS_YP_PIN;
//
// Configure the Y axis touch layer pins as inputs.
//
HWREG(TS_YP_BASE + GPIO_O_DIR) &= ~TS_YP_PIN;
HWREG(TS_YN_BASE + GPIO_O_DIR) &= ~TS_YN_PIN;
//
// The next sample will be a valid X axis sample.
//
g_ui32TSState = TS_STATE_READ_X;
//
// This state has been handled.
//
break;
}
//
// The new sample is an X axis sample that should be processed.
//
case TS_STATE_READ_X: {
//
// Read the raw ADC sample.
//
g_i16TouchX = HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// Clear the analog mode select for the YP pin.
//
HWREG(TS_YP_BASE + GPIO_O_AMSEL) &= ~TS_YP_PIN;
//
// Configure the X and Y axis touch layers as outputs.
//
HWREG(TS_XP_BASE + GPIO_O_DIR) |= TS_XP_PIN;
HWREG(TS_XN_BASE + GPIO_O_DIR) |= TS_XN_PIN;
HWREG(TS_YP_BASE + GPIO_O_DIR) |= TS_YP_PIN;
HWREG(TS_YN_BASE + GPIO_O_DIR) |= TS_YN_PIN;
//
// Drive the positive side of the Y axis touch layer with VDD and
// the negative side with GND. Also, drive both sides of the X
// axis layer with GND to discharge any residual voltage (so that
// a no-touch condition can be properly detected).
//
HWREG(TS_XP_BASE + GPIO_O_DATA + (TS_XP_PIN << 2)) = 0;
HWREG(TS_XN_BASE + GPIO_O_DATA + (TS_XN_PIN << 2)) = 0;
HWREG(TS_YP_BASE + GPIO_O_DATA + (TS_YP_PIN << 2)) = TS_YP_PIN;
HWREG(TS_YN_BASE + GPIO_O_DATA + (TS_YN_PIN << 2)) = 0;
//
// Configure the sample sequence to capture the X axis value.
//
HWREG(ADC0_BASE + ADC_O_SSMUX3) = TS_XP_ADC;
//
// The next sample will be an invalid Y axis sample.
//
g_ui32TSState = TS_STATE_SKIP_Y;
//
// This state has been handled.
//
break;
}
//
// The new sample is a Y axis sample that should be discarded.
//
case TS_STATE_SKIP_Y: {
//
// Read and throw away the ADC sample.
//
HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// Set the analog mode select for the XP pin.
//
HWREG(TS_XP_BASE + GPIO_O_AMSEL) |= TS_XP_PIN;
//
// Configure the X axis touch layer pins as inputs.
//
HWREG(TS_XP_BASE + GPIO_O_DIR) &= ~TS_XP_PIN;
HWREG(TS_XN_BASE + GPIO_O_DIR) &= ~TS_XN_PIN;
//
// The next sample will be a valid Y axis sample.
//
g_ui32TSState = TS_STATE_READ_Y;
//
// This state has been handled.
//
break;
}
//
// The new sample is a Y axis sample that should be processed.
//
case TS_STATE_READ_Y: {
//
// Read the raw ADC sample.
//
g_i16TouchY = HWREG(ADC0_BASE + ADC_O_SSFIFO3);
//
// The next configuration is the same as the initial configuration.
// Therefore, fall through into the initialization state to avoid
// duplicating the code.
//
}
//
// The state machine is in its initial state
//
case TS_STATE_INIT: {
//
// Clear the analog mode select for the XP pin.
//
HWREG(TS_XP_BASE + GPIO_O_AMSEL) &= ~TS_XP_PIN;
//
// Configure the X and Y axis touch layers as outputs.
//
HWREG(TS_XP_BASE + GPIO_O_DIR) |= TS_XP_PIN;
HWREG(TS_XN_BASE + GPIO_O_DIR) |= TS_XN_PIN;
HWREG(TS_YP_BASE + GPIO_O_DIR) |= TS_YP_PIN;
HWREG(TS_YN_BASE + GPIO_O_DIR) |= TS_YN_PIN;
//
// Drive one side of the X axis touch layer with VDD and the other
// with GND. Also, drive both sides of the Y axis layer with GND
// to discharge any residual voltage (so that a no-touch condition
// can be properly detected).
//
HWREG(TS_XP_BASE + GPIO_O_DATA + (TS_XP_PIN << 2)) = TS_XP_PIN;
HWREG(TS_XN_BASE + GPIO_O_DATA + (TS_XN_PIN << 2)) = 0;
HWREG(TS_YP_BASE + GPIO_O_DATA + (TS_YP_PIN << 2)) = 0;
HWREG(TS_YN_BASE + GPIO_O_DATA + (TS_YN_PIN << 2)) = 0;
//
// Configure the sample sequence to capture the Y axis value.
//
HWREG(ADC0_BASE + ADC_O_SSMUX3) = TS_YP_ADC;
//
// If this is the valid Y sample state, then there is a new X/Y
// sample pair. In that case, run the touch screen debouncer.
//
if(g_ui32TSState == TS_STATE_READ_Y) {
TouchScreenDebouncer();
}
//
// The next sample will be an invalid X axis sample.
//
g_ui32TSState = TS_STATE_SKIP_X;
//
// This state has been handled.
//
break;
}
}
}
