StarterWare Touchscreen

Touchscreen

Introduction

The touchscreen module is an 8 channel general purpose ADC,with optional support for interleaving Touchscreen conversation for 4-wire,5-wire, or 8-wire resistive panel. It also has a programmable FSM sequencer that supports 16 steps.A step is a general term for describing which input values to send to the AFE, and how, when , and which channel to sample.For more information on steps please refer to touchscreen TRM.

Programing Sequence

• Module clock for Touchscreen controller is enabled by invoking TSCADCModuleClkConfig() API.
• AN0 - AN7 input pins are multiplexed by invoking TSCADCPinMuxSetUp() API.
• Input ADC Clock is configured by invoking TSCADCConfigureAFEClock() API.
• Step Configuration register are write protected.Thus,before configuring any step register, write protection for step configuration register must be disabled by invoking TSCStepConfigProtectionDisable();

• Configuring IdleStep.
  • A IdleStep can be configured to select required input channel and reference voltage by invoking TSCADCIdleStepConfig();
  • A IdleStep can be configured to drive xpp,xnp and ypp pin to high,which in turn pull up the AN0-AN2 line by invoking TSCADCIdleStepAnalogSupplyConfig() API
  • A IdleStep can be configured to drive the xnn,ypn,ynn and wpn pin to low,which in turn pull down AN1-AN4 line by invoking TSCADCIdleStepAnalogGroundConfig() API.
  • ADC can be configured for differential or singled ended mode of operation by invoking TSCADCIdleStepOperationModeControl() API.

• Configuring ChargeStep.
  • A ChargeStep can be configured to select required input channel and reference voltage by invoking TSCADCChargeStepConfig();
  • A ChargeStep can be configured to drive xpp,xnp and ypp pin to high,which in turn pull up the AN0-AN2 line by invoking TSCADCChargeStepAnalogSupplyConfig() API
  • A ChargeStep can be configured to drive the xnn,ypn,ynn and wpn pin to low,which in turn pull down AN1-AN4 line by invoking TSCADCChargeStepAnalogGroundConfig() API.
  • ADC can be configured for differential or singled ended mode of operation by invoking TSCADCChargeStepOperationModeControl() API.
  • Charge delay is configured by invoking TSCADCTSChargeStepOpenDelayConfig() API.

• Configuring Steps to measure x and y.
  • A step can be configured to select required input channel and reference voltage by invoking TSCADCTSStepConfig();
  • A step can be configured to drive xpp,xnp and ypp pin to high,which in turn pull up the AN0-AN2 line by invoking TSCADCTSStepAnalogSupplyConfig() API
  • A step can be configured to drive the xnn,ypn,ynn and wpn pin to low,which in turn pull down AN1-AN4 line by invoking TSCADCTSStepAnalogGroundConfig() API.
  • A step can configured to store data,which is an outcome after a step is applied by FSM,in either FIFO 0 or 1 by invoking TSCADCTSStepFIFOSelConfig() API.
  • A step can be configured in continuous or one-shot mode for software enabled or HW event mapped step by invoking TSCADCTSStepConfig() API.
  • ADC can be configured for differential or singled ended mode of operation by invoking TSCADCTSStepOperationModeControl() API.
  • Open and Sample delay for step configured by invoking TSCADCTSStepOpenDelayConfig() and TSCADCTSStepSampleDelayConfig() .
• AFE can be configured for 4-wire or 5-wire or as general purpose inputs by invoking TSCTSModeConfig();
• Touchscreen transistors are enabled by invoking TSCADCTransistorConfig() API.
• Map hardware event to pen touch IRQ by invoking TSCADCHWEventMapSet() API.
• Required steps can be enabled by invoking TSCConfigureStepEnable() API.
• TSC is enabled by invoking TSCModuleStateSet() API.