InetrfaceProducts NXP
PCA9955A and PCA9956A class library. The PCA9955A is a 16-channel and the PCA9956A is a 24-channel Fm+ I2C-bus 57mA/20V constant current LED driver. The PCA9955A has a extended feature which called "Gradation control".
Dependents: PCA9956A_Hello pca9956b_two_demoboards PCA9955A_Gradation_control PCA9955A_Gradation_control ... more
What is this?
Code for PCA9956A and PCA9955A.
24-channel and 16-channel constant current type LED driver component class.
Please refer to the component page for details
High-level API is available
A high-level API that can be used as the "PwmOut" of bed-SDK is available.
This API enables to make instances of each LED output pins and control PWM duty cycle by assignment.
Output current also controllable by API function.
For detail information, refer API document of LedPwmOutCC Class class which is included in PCA995xA class library.
#include "mbed.h"
#include "PCA9956A.h"
PCA9956A led_cntlr( p28, p27, 0xC4 ); // SDA, SCL, Slave_address(option)
LedPwmOutCC led( led_cntlr, L0 );
int main()
{
while( 1 ) {
for( float p = 0.0f; p < 1.0f; p += 0.1f ) {
led = p;
wait( 0.1 );
}
}
}
About the chips
PCA9956A
The PCA9956A is an I2C-bus controlled 24-channel constant current LED driver optimized for dimming and blinking 57 mA LEDs. Each LED output has its own 8-bit resolution (256 steps) fixed frequency individual PWM controller that operates at 31.25 kHz with a duty cycle that is adjustable from 0 % to 99.6 % to allow the LED to be set to a specific brightness value.
Datasheet: http://www.nxp.com/documents/data_sheet/PCA9956A.pdf
PCA9955A
The PCA9955A is an I2C-bus controlled 16-channel constant current LED driver optimized for dimming and blinking 57 mA Red/Green/Blue/Amber (RGBA) LEDs in amusement products. Each LED output has its own 8-bit resolution (256 steps) fixed frequency individual PWM controller that operates at 31.25 kHz with a duty cycle that is adjustable from 0 % to 100 % to allow the LED to be set to a specific brightness value.
On addition to this, the PCA9955A has "Gradation control".
The gradation control is a new feature of PCA995xA series. After the register setting and start the control, the PCA9955A performs dimming cycles automatically without MCU intervention.
Datasheet: http://www.nxp.com/documents/data_sheet/PCA9955A.pdf
PCA9952 and PCA9955 (non-A version)
The PCA9955 and PCA9955 (no-A at end of the type number) is not supported by this component class.
PCA9955(non-A)
PCA9955A != PCA9955
PCA9955A is not software compatible to PCA9955(non-A version).
There are several differences between A and non-A versions.
Register mapping is one of the difference. Please make sure you are using PCA9955A.
How the API works?
When the instance is made, all set up for PWM operation are done automatically.
For the operation, user can control the LED brightness in two ways.
- PWM
- Current
PCA9955A and PCA9956A have internal 31.25kHz oscillator to generate internal PWM waveform. This signal switchs the output current ON and OFF. The class' function pwm() controls duty-cycle of this output.
Another control is current. Since the PCA9955A and PCA9956A are constant current type LED driver, those have internal current sources. The current source on each channels has independent control of output current. The class' function current() provides interface to current change.
Tips for the chips
PCA995xA family
This PCA995xA components library can be used for both PCA9955A(16-channel) and PCA9956A(24-channel).
If you are using both chips on the I2C bus, those can be operated like..
#include "mbed.h"
#include "PCA9955A.h"
#include "PCA9956A.h"
PCA9955A led0( p28, p27, 0xC0 ); // SDA, SCL, Slave_address=0xC0 (16-channel chip)
PCA9956A led1( p28, p27, 0xC2 ); // SDA, SCL, Slave_address=0xC2 (24-channel chip)
int main()
{
led0.current( ALLPORTS, 1.0 ); // Set all ports output current 100%
led1.current( ALLPORTS, 1.0 ); // Set all ports output current 100%
led0.pwm( .... // PWM control for PCA9955A(16-channel chip)
led1.pwm( .... // PWM control for PCA9956A(24-channel chip)
...
Other sample code
For PCA9955A : http://developer.mbed.org/users/nxp_ip/code/PCA9955A_Hello/
For PCA9956A : http://developer.mbed.org/users/nxp_ip/code/PCA9956A_Hello/
For Gradation control of PCA9955A http://developer.mbed.org/users/nxp_ip/code/PCA9955A_Gradation_control/
PCA9956A/PCA9956A.h
- Committer:
- nxp_ip
- Date:
- 22 months ago
- Revision:
- 10:0d865f257fd2
- Parent:
- 9:17dd2d8fb866
File content as of revision 10:0d865f257fd2:
/** PCA9956A constant current LED driver
*
* An operation sample of PCA9956A 24-channel Fm+ I2C-bus 57mA/20V constant current LED driver.
* mbed accesses the PCA9956A registers through I2C.
*
* @class PCA9956A
* @author Akifumi (Tedd) OKANO, NXP Semiconductors
* @version 0.6
* @date 19-Mar-2015 (minor fix on 17-Jun-2022)
*
* Released under the Apache 2 license
*
* About PCA9956A:
* http://www.nxp.com/products/interface_and_connectivity/i2c/i2c_led_display_control/PCA9956ATW.html
*/
#ifndef MBED_PCA9956A
#define MBED_PCA9956A
#include "mbed.h"
#include "PCA995xA.h"
#include "LedPwmOutCC.h"
/** PCA9956A class
*
* This is a driver code for the PCA9956A 24-channel Fm+ I2C-bus 57mA/20V constant current LED driver.
* This class provides interface for PCA9956A operation and accessing its registers.
* Detail information is available on next URL.
* http://www.nxp.com/products/interface_and_connectivity/i2c/i2c_led_display_control/PCA9956ATW.html
*
* Next sample code shows operation based on low-level-API (operated by just device instane)
*
* Example:
* @code
* // PCA9956A operation sample using its device instance
*
* #include "mbed.h"
* #include "PCA9956A.h"
*
* PCA9956A led_cntlr( p28, p27, 0x02 ); // SDA, SCL, Slave_address(option)
*
* int main()
* {
* led_cntlr.current( ALLPORTS, 1.0 ); // Set all ports output current 100%
*
* while(1) {
* for ( int port = 0; port < led_cntlr.number_of_ports(); port++ ) {
* for ( int i = 1; i <= 100; i++ ) {
* led_cntlr.pwm( port, (float)i / 100.0 );
* wait( 0.01 );
* }
* }
* led_cntlr.pwm( ALLPORTS, 0.0 );
* }
* }
* @endcode
*
* The high-level-API:LedPwmOutCC is also available.
* It can be used like next sample code.
*
* @code
* // PCA9956A operation sample using high-level-API
*
* #include "mbed.h"
* #include "PCA9956A.h"
*
* PCA9956A led_cntlr( p28, p27, 0x02 ); // SDA, SCL, Slave_address(option)
* LedPwmOutCC led0( led_cntlr, L0 ); // Instance for LED0 pin
* LedPwmOutCC led1( led_cntlr, L1 ); // Instance for LED1 pin
* LedPwmOutCC led2( led_cntlr, L2 ); // Instance for LED2 pin
*
* int main()
* {
* led0.current( 0.5 ); // LED0 pin current output setting to 50%
* led1.current( 0.5 ); // LED1 pin current output setting to 50%
* led2.current( 0.5 ); // LED2 pin current output setting to 50%
*
* while(1) {
*
* for ( float p = 1.0; p >= 0.0; p -= 0.01 ) {
* led0 = p; // Set LED0 output PWM dutycycle as 'p'
* wait( 0.01 );
* }
*
* for ( float p = 1.0; p >= 0.0; p -= 0.01 ) {
* led1 = p; // Set LED1 output PWM dutycycle as 'p'
* wait( 0.01 );
* }
*
* for ( float p = 1.0; p >= 0.0; p -= 0.01 ) {
* led2 = p; // Set LED2 output PWM dutycycle as 'p'
* wait( 0.01 );
* }
* }
* }
* @endcode
*/
class PCA9956A : public PCA995xA
{
public:
#if DOXYGEN_ONLY
/** PCA9956A pin names high-level API i.e. LedPwmOutCC */
typedef enum {
L0, /**< LED0 pin */
L1, /**< LED1 pin */
L2, /**< LED2 pin */
L3, /**< LED3 pin */
L4, /**< LED4 pin */
L5, /**< LED5 pin */
L6, /**< LED6 pin */
L7, /**< LED7 pin */
L8, /**< LED8 pin */
L9, /**< LED9 pin */
L10, /**< LED10 pin */
L11, /**< LED11 pin */
L12, /**< LED12 pin */
L13, /**< LED13 pin */
L14, /**< LED14 pin */
L15, /**< LED15 pin */
L16, /**< LED16 pin */
L17, /**< LED17 pin */
L18, /**< LED18 pin */
L19, /**< LED19 pin */
L20, /**< LED20 pin */
L21, /**< LED21 pin */
L22, /**< LED22 pin */
L23, /**< LED23 pin */
L_NC = ~0x0L /**< for when the pin is left no-connection */
} LedPinName;
#endif // DOXYGEN_ONLY
/** Name of the PCA9956A registers (for direct register access) */
enum command_reg {
MODE1, /**< MODE1 register */
MODE2, /**< MODE2 register */
LEDOUT0, /**< LEDOUT0 register */
LEDOUT1, /**< LEDOUT1 register */
LEDOUT2, /**< LEDOUT2 register */
LEDOUT3, /**< LEDOUT3 register */
LEDOUT4, /**< LEDOUT4 register */
LEDOUT5, /**< LEDOUT5 register */
GRPPWM, /**< GRPPWM register */
GRPFREQ, /**< GRPFREQ register */
PWM0, /**< PWM0 register */
PWM1, /**< PWM1 register */
PWM2, /**< PWM2 register */
PWM3, /**< PWM3 register */
PWM4, /**< PWM4 register */
PWM5, /**< PWM5 register */
PWM6, /**< PWM6 register */
PWM7, /**< PWM7 register */
PWM8, /**< PWM8 register */
PWM9, /**< PWM9 register */
PWM10, /**< PWM10 register */
PWM11, /**< PWM11 register */
PWM12, /**< PWM12 register */
PWM13, /**< PWM13 register */
PWM14, /**< PWM14 register */
PWM15, /**< PWM15 register */
PWM16, /**< PWM16 register */
PWM17, /**< PWM17 register */
PWM18, /**< PWM18 register */
PWM19, /**< PWM19 register */
PWM20, /**< PWM20 register */
PWM21, /**< PWM21 register */
PWM22, /**< PWM22 register */
PWM23, /**< PWM23 register */
IREF0, /**< IREF0 register */
IREF1, /**< IREF1 register */
IREF2, /**< IREF2 register */
IREF3, /**< IREF3 register */
IREF4, /**< IREF4 register */
IREF5, /**< IREF5 register */
IREF6, /**< IREF6 register */
IREF7, /**< IREF7 register */
IREF8, /**< IREF8 register */
IREF9, /**< IREF9 register */
IREF10, /**< IREF10 register */
IREF11, /**< IREF11 register */
IREF12, /**< IREF12 register */
IREF13, /**< IREF13 register */
IREF14, /**< IREF14 register */
IREF15, /**< IREF15 register */
IREF16, /**< IREF16 register */
IREF17, /**< IREF17 register */
IREF18, /**< IREF18 register */
IREF19, /**< IREF19 register */
IREF20, /**< IREF20 register */
IREF21, /**< IREF21 register */
IREF22, /**< IREF22 register */
IREF23, /**< IREF23 register */
OFFSET = 0x3A, /**< OFFSET register */
SUBADR1, /**< SUBADR1 register */
SUBADR2, /**< SUBADR2 register */
SUBADR3, /**< SUBADR3 register */
ALLCALLADR, /**< ALLCALLADR register */
PWMALL, /**< PWMALL register */
IREFALL, /**< IREFALL register */
EFLAG0, /**< EFLAG0 register */
EFLAG1, /**< EFLAG1 register */
EFLAG2, /**< EFLAG2 register */
EFLAG3, /**< EFLAG3 register */
EFLAG4, /**< EFLAG4 register */
EFLAG5, /**< EFLAG5 register */
REGISTER_START = MODE1,
LEDOUT_REGISTER_START = LEDOUT0,
PWM_REGISTER_START = PWM0,
IREF_REGISTER_START = IREF0,
};
/** Create a PCA9956A instance connected to specified I2C pins with specified address
*
* @param i2c_sda I2C-bus SDA pin
* @param i2c_sda I2C-bus SCL pin
* @param i2c_address I2C-bus address (default: 0xC0)
*/
PCA9956A( PinName i2c_sda, PinName i2c_scl, char i2c_address = PCA995xA::DEFAULT_I2C_ADDR );
/** Create a PCA9956A instance connected to specified I2C pins with specified address
*
* @param i2c_obj I2C object (instance)
* @param i2c_address I2C-bus address (default: 0xC0)
*/
PCA9956A( I2C &i2c_obj, char i2c_address = PCA995xA::DEFAULT_I2C_ADDR );
/** Destractor
*
*/
virtual ~PCA9956A();
/** Returns the number of output ports
*
* @returns
* The number of output ports
*/
virtual int number_of_ports( void );
#if DOXYGEN_ONLY
/** Set the output duty-cycle, specified as a percentage (float)
*
* @param port Selecting output port
* 'ALLPORTS' can be used to set all port duty-cycle same value.
* @param v A floating-point value representing the output duty-cycle,
* specified as a percentage. The value should lie between
* 0.0f (representing on 0%) and 1.0f (representing on 99.6%).
* Values outside this range will have undefined behavior.
*/
void pwm( int port, float v );
/** Set all output port duty-cycle, specified as a percentage (array of float)
*
* @param vp Aray to floating-point values representing the output duty-cycle,
* specified as a percentage. The value should lie between
* 0.0f (representing on 0%) and 1.0f (representing on 99.6%).
*
* @note
* The aray should have length of 24
*/
void pwm( float *vp );
/** Set the output current, specified as a percentage (float)
*
* @param port Selecting output port
* 'ALLPORTS' can be used to set all port current same value.
* @param v A floating-point value representing the output current,
* specified as a percentage. The value should lie between
* 0.0f (representing on 0%) and 1.0f (representing on 100%).
* Values outside this range will have undefined behavior.
*/
void current( int port, float vp );
/** Set all output port curent, specified as a percentage (array of float)
*
* @param vp Aray to floating-point values representing the output current,
* specified as a percentage. The value should lie between
* 0.0f (representing on 0%) and 1.0f (representing on 100%).
*
* @note
* The aray should have length of 24
*/
void current( float *vP );
/** Register write (single byte) : Low level access to device register
*
* @param reg_addr Register address
* @param data Value for setting into the register
*/
void write( char reg_addr, char data );
/** Register write (multiple bytes) : Low level access to device register
*
* @param data Pointer to an array. First 1 byte should be the writing start register address
* @param length Length of data
*/
void write( char *data, int length );
/** Register read (single byte) : Low level access to device register
*
* @param reg_addr Register address
* @return Read value from register
*/
char read( char reg_addr );
/** Register write (multiple bytes) : Low level access to device register
*
* @param reg_addr Register address
* @param data Pointer to an array. The values are stored in this array.
* @param length Length of data
*/
void read( char reg_addr, char *data, int length );
#endif
private:
void initialize( void );
virtual char pwm_register_access( int port );
virtual char current_register_access( int port );
const int n_of_ports;
}
;
#endif // MBED_PCA9956A
PCA9955B, PCA9956B : 16 & 24-channel constant current LED driver