Diff: PCA9685.cpp

Revision:

0:aa965d6b1f8f

Child:

1:9d6633a308ba

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PCA9685.cpp	Tue Apr 05 21:20:15 2016 +0000
@@ -0,0 +1,131 @@
+#include "mbed.h"
+#include "PCA9685.h"
+#include "definitions.h"
+
+PCA9685::PCA9685(uint8_t i2c_address, I2C i2c_object, float frequency) : i2c_addr(i2c_address), freq(frequency), i2c(i2c_object)
+{
+    //int two = 1 + 1;
+
+}
+
+void PCA9685::init(void) {
+    
+    reset();
+    
+    uint8_t prescale = (uint8_t) (OSC_CLOCK / (4096 * freq)) - 1;
+    
+    write_8(MODE1, 0x21); //0010 0001 : AI ENABLED
+    write_8(MODE2, 0x07); //0000 0111 : NOT INVRT, CHANGE ON STOP, TOTEM POLE, \OE = 1, LEDn = HIGH IMP
+    
+    set_prescale(prescale);
+    
+    
+       
+}
+
+void PCA9685::reset(void) {
+        
+    write_8(MODE1,0x00);
+        
+}
+
+void PCA9685::set_prescale(uint8_t prescale) {
+    
+    uint8_t oldmode = read_8(MODE1);
+    uint8_t newmode = (oldmode&0x7F) | 0x10; // set the sleep bit
+
+    write_8(MODE1, newmode); // send the device to sleep
+    wait_ms(5);
+    write_8(PRESCALE, prescale); // set the prescaler
+    write_8(MODE1, oldmode);
+    wait_ms(5);
+    write_8(MODE1, oldmode | 0xa1); // wake up the device
+    
+}
+
+
+//NB REQUIRES AUTO-INCREMENT MODE ENABLED
+//0 <= pwm_output <= 15
+//0 <= (count_on || count_off) <= 4095
+void PCA9685::set_pwm_output(int pwm_output, uint16_t count_on, uint16_t count_off) {
+    
+    char msg[5];
+
+    msg[0] = LED0_ON_L + (4 * pwm_output);
+    msg[1] = count_on;
+    msg[2] = count_on >> 8;
+    msg[3] = count_off;
+    msg[4] = count_off >> 8;
+
+    i2c.write(ADDR, msg, 5);
+    
+}
+
+
+//NB REQUIRES AUTO-INCREMENT MODE ENABLED
+//0 <= pwm_output <= 15
+void PCA9685::set_pwm_duty(int pwm_output, float duty_cycle) {
+    
+    if (duty_cycle > 1.0) { duty_cycle = 1.0; }
+    if (duty_cycle < 0.0) { duty_cycle = 0.0; }
+    
+    uint16_t count_off = (uint16_t) (duty_cycle * 4095);
+    uint16_t count_on = 0x0000;
+    
+    set_pwm_output(pwm_output, count_on, count_off);
+    
+}
+
+
+//NB REQUIRES AUTO-INCREMENT MODE ENABLED
+//0 <= pwm_output <= 15
+void PCA9685::set_pwm_pw(int pwm_output, float pulse_width_us) {
+    
+    float period_us = (1e6/freq);
+        
+    float duty = pulse_width_us/period_us;
+    
+    set_pwm_duty(pwm_output, duty);
+       
+}
+    
+
+void PCA9685::update(void) {
+    
+    i2c.stop();
+
+}
+    
+
+
+void PCA9685::write_8(uint8_t reg, uint8_t msg) {
+    
+    char send[2]; //Store the address and data in an array
+    send[0] = reg;
+    send[1] = msg;
+    i2c.write(i2c_addr, send, 2);
+    
+}
+
+uint8_t PCA9685::read_8(uint8_t reg) {
+    
+    char send[1] ;
+    send[0] = reg;
+    i2c.write(i2c_addr, send, 1);
+    char recieve[1];
+    i2c.read(i2c_addr, recieve, 1);
+    return recieve[0];
+    
+}    
+
+int PCA9685::convert_pwm_value(float pulse_width_us, float period_us) { 
+
+    int result;
+    float interim;
+    
+    interim = ((pulse_width_us / period_us) * 4095); //scale the pulse width to a 12-bit scale
+    result = (int) interim; //round the value to the nearest integer
+    
+    return result;
+    
+}   
\ No newline at end of file