Diff: PCA9685.cpp

Revision:

0:c7f4744deec3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/PCA9685.cpp	Wed Jul 22 08:06:28 2015 +0000
@@ -0,0 +1,62 @@
+#include "PCA9685.h"
+#include "mbed.h"
+PCA9685::PCA9685(PinName sda, PinName scl, int addr) : i2c(sda, scl), _i2caddr(addr) {}
+
+void PCA9685::begin(void)
+{
+    reset();
+}
+
+void PCA9685::frequencyI2C(int freq)
+{
+    i2c.frequency(freq);
+}
+void PCA9685::write8(uint8_t address, uint8_t data)
+{
+    char cmd[2];
+    cmd[0] = address;
+    cmd[1] = data;
+    i2c.write(_i2caddr, cmd, 2);
+}
+
+char PCA9685::read8(char address)
+{
+    i2c.write(_i2caddr, &address, 1);
+    char rtn;
+    i2c.read(_i2caddr, &rtn, 1);
+    return rtn;
+}
+
+void PCA9685::reset(void)
+{
+    write8(PCA9685_MODE1, 0x0);
+}
+void PCA9685::setPrescale(uint8_t prescale) {
+    uint8_t oldmode = read8(PCA9685_MODE1);
+    uint8_t newmode = (oldmode&0x7F) | 0x10; // sleep
+    write8(PCA9685_MODE1, newmode); // go to sleep
+    wait_ms(5);
+    write8(PCA9685_PRESCALE, prescale); // set the prescaler
+    write8(PCA9685_MODE1, oldmode);
+    wait_ms(5);
+    write8(PCA9685_MODE1, oldmode | 0xa1);
+}
+void PCA9685::setPWMFreq(float freq)
+{
+    float prescaleval = 25000000;
+    prescaleval /= 4096;
+    prescaleval /= freq;
+    uint8_t prescale = floor(prescaleval  + 0.5) - 1;
+    setPrescale(prescale);
+}
+
+void PCA9685::setPWM(uint8_t num, uint16_t on, uint16_t off)
+{
+    char cmd[5];
+    cmd[0] = LED0_ON_L + 4 * num;
+    cmd[1] = on;
+    cmd[2] = on >> 8;
+    cmd[3] = off;
+    cmd[4] = off >> 8;
+    i2c.write(_i2caddr, cmd, 5);
+}