InetrfaceProducts NXP / PCAL955x

The PCAL9555, PCAL9554 series is a low-voltage 16-bit/8-bit General Purpose Input/Output (GPIO) expander with interrupt. This conponent library is compatible to basic operation os GPIO expanders: PCAL9555, PCA9555, PCA9535, PCA9539, PCAL9554, PCA9554 and PCA9538. On addition to this, this library is including mbed-SDK-style APIs. APIs that similar to DigitaiInOut, DigitalOut, DigitalIn, BusInOUt, BusOut and BusIn are available.

Dependents:   PCAL9555_Hello OM13082-JoyStick OM13082_LED OM13082-test ... more

What is this?

This conponent library is compatible to basic operation os GPIO expanders: PCAL9555, PCA9555, PCA9535, PCA9539, PCAL9554, PCA9554 and PCA9538 .

On addition to this, this library is including mbed-SDK-style APIs. APIs that similar to DigitaiInOut, DigitalOut, DigitalIn, BusInOut, BusOut and BusIn are available.

How to use?

Wiring

/media/uploads/nxp_ip/gpio16.png
Wiring between mbed and 16-bit GPIO expander

/media/uploads/nxp_ip/gpio08.png
Wiring between mbed and 8-bit GPIO expander

Very basic register level I/O bit operation

PCAL9555 and PCAL9554 are class libraries for those compatible GPIO expander chips.
Those class libraries provides interface for bit operation of its I/O port.
For 16-bit GPIO expanders, the input/output access and its direction setting can be done by 16-bit data. For 8-bit GPIO expanders, those can be done by 8-bit data.

  #include    "mbed.h"
  #include    "PCAL9555.h"
 
  PCAL9555    gpio( p28, p27, 0xE8 );     //  using PCA9539
 
  int main() {
      gpio.configure( 0xFFFF );           //  Set all pins: input
      printf( "  0x%04X\r\n", (int)gpio );//  Print pins state
 
      gpio.configure( 0x0000 );           //  Set all pins: output
      int count   = 0;
      while(1) {
          gpio.write( count++ );
      }
  }


High level APIs

To use the GPIO expanders more simple, this library is including mbed-SDK-style APIs.
APIs that similar to DigitaiInOut, DigitalOut, DigitalIn, BusInOut, BusOut and BusIn are available.

GpioDigitalOut, GpioDigitaiInOut, GpioDigitalIn

Next code shows sample of DigitalOut equivalent API GpioDigitalOut usage.
A pin on the PCAL9555 is defined as pin and its state is changed by assignment.
(For single pin operation, GpioDigitaiInOut and GpioDigitalIn are available also.)

  #include "mbed.h"
  #include "PCAL9555.h"
  
  PCAL9555        gpio_exp( p28, p27, 0xE8 );    //  SDA, SCL, Slave_address(option)
  GpioDigitalOut  pin( gpio_exp, X0_0 );
   
  int main() {
      while( 1 ) {
          pin = 1;
          wait( 0.2 );
          pin = 0;
          wait( 0.2 );
      }
  }


GpioBusOut, GpioBusInOut, GpioBusIn

BusOut equivalent API GpioBusOut is available too.
In next code, pins are grouped as mypins to manage the output as bus output.
(Same as GpioDigitalInOut and GpioDigitalIn APIs, GpioBusInOut and GpioBusIn are available also.)

  #include "mbed.h"
  #include "PCAL9555.h"
  
  PCAL9555    gpio_exp( p28, p27, 0xE8 );    //  SDA, SCL, Slave_address(option)
  GpioBusOut  mypins( gpio_exp, X0_0, X0_1, X0_2, X0_3 );
   
  int main() {
      while( 1 ) {
          for( int i = 0; i < 16; i++ ) {
              mypins  = i;
              wait( 0.25 );
          }
      }
  }


The high level APIs can be used in combination

Those high level APIs can be used in combination.
Each pins can be managed by instances. 

  #include    "mbed.h"
  #include    "PCAL9555.h"
 
  PCAL9555        gpio( p28, p27, 0xE8 );     //  using PCA9539
 
  //  The GPIO pins are grouped in some groups and operated as bus I/O
  GpioBusIn       bus_in( gpio, X0_0, X0_1, X0_2, X0_3 );
  GpioBusOut      bus_out( gpio, X0_4, X0_5, X0_6 );
  GpioBusInOut    bus_io( gpio, X1_7, X1_6, X1_5, X1_4, X1_3, X1_2, X1_1, X1_0 );
  GpioDigitalOut  myled( gpio, X0_7 );
 
  int main() {
      bus_io.input();
      printf( "I/O = 0x%02X\r\n", (int)bus_io );
      printf( "In  = 0x%01X\r\n", (int)bus_in );
 
      bus_io.output();
 
      int count   = 0;
      while(1) {
          bus_out = count;
          bus_io  = count;
          myled   = count & 0x1;
          count++;
          wait( 0.1 );
      }
  }

Diff: base_classes/CompGpioExp/GpioBus/GpioBusIn.h

Revision:
0:6c9a51a50eea
Child:
1:fd7cfa821b6a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/base_classes/CompGpioExp/GpioBus/GpioBusIn.h	Sat Mar 07 12:56:05 2015 +0000
@@ -0,0 +1,76 @@
+/** GpioBusIn API for GPIO-expander component class 
+ *
+ *  @author  Akifumi (Tedd) OKANO, NXP Semiconductors
+ *  @version 0.5
+ *  @date    07-Mar-2015
+ *
+ *  Released under the Apache 2 license
+ */
+
+#ifndef     MBED_GpioBusIn
+#define     MBED_GpioBusIn
+
+#include    "mbed.h"
+#include    "GpioBusInOut.h"
+
+/** GpioDigitalIn class
+ *
+ *  @class GpioDigitalIn
+ *
+ *  "GpioDigitalIn" class works like "DigitalIn" class of mbed-SDK. 
+ *  This class provides pin oriented API, abstracting the GPIO-expander chip. 
+ *
+ *  Example:
+ *  @code
+ *  #include "mbed.h"
+ *  #include "PCAL9555.h"
+ *  
+ *  PCAL9555    gpio_exp( p28, p27, 0xE8 );    //  SDA, SCL, Slave_address(option)
+ *  GpioBusIn   nibble( gpio_exp, X0_0, X0_1, X0_2, X0_3 );
+ *   
+ *  int main() {
+ *      while ( 1 ) {
+ *          switch ( nibble ) {
+ *              case 0x3: printf( "Hello!\n" ); break; // X0_0 and X0_1 are 1
+ *              case 0x8: printf( "World!\n" ); break; // X0_3 is 1
+ *          }
+ *      }
+ *  }
+ *  @endcode
+ */
+class GpioBusIn : public GpioBusInOut
+{
+public:
+
+    /** Create an GpioBusIn, connected to the specified pins
+     *
+     *  @param gpiop    Instance of GPIO expander device
+     *  @param p<n>     DigitalInOut pin to connect to bus bit p<n> (GpioPinName)
+     *
+     *  @note
+     *    It is only required to specify as many pin variables as is required
+     *    for the bus; the rest will default to NC (not connected)
+     */
+    GpioBusIn( CompGpioExp &gpiop,
+               GpioPinName p0,         GpioPinName p1  = X_NC, GpioPinName p2  = X_NC, GpioPinName p3  = X_NC,
+               GpioPinName p4  = X_NC, GpioPinName p5  = X_NC, GpioPinName p6  = X_NC, GpioPinName p7  = X_NC,
+               GpioPinName p8  = X_NC, GpioPinName p9  = X_NC, GpioPinName p10 = X_NC, GpioPinName p11 = X_NC,
+               GpioPinName p12 = X_NC, GpioPinName p13 = X_NC, GpioPinName p14 = X_NC, GpioPinName p15 = X_NC );
+    GpioBusIn( CompGpioExp &gpiop, GpioPinName pins[ 16 ] );
+
+    /**
+     *  Destractor
+     */
+    virtual     ~GpioBusIn();
+
+    /** A shorthand for read()
+     */
+    operator int( void );
+
+private:
+    GpioBusIn& operator= ( int rhs );
+    GpioBusIn& operator= ( GpioBusIn& rhs );
+}
+;
+
+#endif  //  MBED_GpioBusIn