Sam Grove / MPR121

A device driver for the Freescale MPR121 capactive touch IC. Not optimized for any particular system, just a starting point to get the chip up in running in no time. Changes to registers init() method will tailor the library for end system use.

Dependents:   Seeed_Grove_I2C_Touch_Example MPR121_HelloWorld mbed_petbottle_holder_shikake test_DEV-10508 ... more

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MPR121 Class Reference
Public Types | Public Member Functions

MPR121 Class Reference

Using the Sparkfun SEN-10250 BoB. More...

#include <MPR121.h>

Public Types

enum  MPR121_ADDR { ADDR_VSS = 0x5A, ADDR_VDD, ADDR_SCL, ADDR_SDA }
 

Possible terminations for the ADDR pin.

More...
enum  MPR121_REGISTER
 

The device register map.

More...

Public Member Functions

 MPR121 (I2C &i2c, InterruptIn &pin, MPR121_ADDR i2c_addr)
 Create the MPR121 object.
void init (void)
 Clear state variables and initilize the dependant objects.
void enable (void)
 Allow the IC to run and collect user input.
void disable (void)
 Stop the IC and put into low power mode.
uint32_t isPressed (void)
 Determine if a new button press event occured Upon calling the state is cleared until another press is detected.
uint16_t buttonPressed (void)
 Get the electrode status (ELE12 ...
void registerDump (Serial &obj) const
 print the register map and values to the console
void writeRegister (MPR121_REGISTER const reg, uint8_t const data) const
 Write to a register (exposed for debugging reasons) Note: most writes are only valid in stop mode.
uint8_t readRegister (MPR121_REGISTER const reg) const
 Read from a register (exposed for debugging reasons)

Detailed Description

Using the Sparkfun SEN-10250 BoB.

Example: 

  #include "mbed.h"
  #include "MPR121.h"
  
  Serial pc(USBTX, USBRX);
  DigitalOut myled(LED1);
  
  #if defined TARGET_LPC1768 || TARGET_LPC11U24
    I2C i2c(p28, p27);
    InterruptIn irq(p26);
    MPR121 touch_pad(i2c, irq, MPR121::ADDR_VSS );
  
  #elif defined TARGET_KL25Z
    I2C i2c(PTC9, PTC8);
    InterruptIn irq(PTA5);
    MPR121 touch_pad(i2c, irq, MPR121::ADDR_VSS );
  
  #else
    #error TARGET NOT TESTED
  #endif
  
  int main()  
  {       
      touch_pad.init();
      touch_pad.enable();
      
      while(1)
      {
          if(touch_pad.isPressed())
          {
              uint16_t button_val = touch_pad.buttonPressed();
              printf("button = 0x%04x\n", button_val);
              myled = (button_val>0) ? 1 : 0;
          }            
      }
  }

API for the MPR121 capacitive touch IC

Definition at line 74 of file MPR121.h.

Member Enumeration Documentation

enum MPR121_ADDR

Possible terminations for the ADDR pin.

Enumerator:
ADDR_VSS 

ADDR connected to VSS

ADDR_VDD 

ADDR connected to VDD

ADDR_SCL 

ADDR connected to SDA

ADDR_SDA 

ADDR connected to SCL

Definition at line 94 of file MPR121.h.

enum MPR121_REGISTER

The device register map.

Definition at line 106 of file MPR121.h.

Constructor & Destructor Documentation

MPR121 ( I2C &  i2c,
InterruptIn &  pin,
MPR121_ADDR  i2c_addr 
)

Create the MPR121 object.

Parameters:
i2c- A defined I2C object
pin- A defined InterruptIn object
i2c_addr- Connection of the address line

Definition at line 28 of file MPR121.cpp.

Member Function Documentation

uint16_t buttonPressed ( void   )

Get the electrode status (ELE12 ...

ELE0 -> b15 xxx b11 ... b0 The buttons are bit mapped. ELE0 = b0 ... ELE11 = b11 b12 ... b15 undefined

Returns:
The state of all buttons

Definition at line 123 of file MPR121.cpp.

void disable ( void   )

Stop the IC and put into low power mode.

Definition at line 104 of file MPR121.cpp.

void enable ( void   )

Allow the IC to run and collect user input.

Definition at line 91 of file MPR121.cpp.

void init ( void   )

Clear state variables and initilize the dependant objects.

Definition at line 37 of file MPR121.cpp.

uint32_t isPressed ( void   )

Determine if a new button press event occured Upon calling the state is cleared until another press is detected.

Returns:
1 if a press has been detected since the last call, 0 otherwise

Definition at line 118 of file MPR121.cpp.

uint8_t readRegister ( MPR121_REGISTER const   reg ) const

Read from a register (exposed for debugging reasons)

Parameters:
reg- The register to read from
Returns:
The register contents

Definition at line 182 of file MPR121.cpp.

void registerDump ( Serial &  obj ) const

print the register map and values to the console

Parameters:
obj- a Serial object that prints to a console

Definition at line 129 of file MPR121.cpp.

void writeRegister ( MPR121_REGISTER const   reg,
uint8_t const   data 
) const

Write to a register (exposed for debugging reasons) Note: most writes are only valid in stop mode.

Parameters:
reg- The register to be written
data- The data to be written

Definition at line 167 of file MPR121.cpp.

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