Diff: AD9837.h

Revision:

0:fdfd54fe27dc

diff -r 000000000000 -r fdfd54fe27dc AD9837.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/AD9837.h	Tue Jun 30 08:25:56 2015 +0000
@@ -0,0 +1,52 @@
+#include "mbed.h"
+
+enum SignOutput {
+    SIGN_OUTPUT_NONE        = 0x0000,
+    SIGN_OUTPUT_MSB         = 0x0028,
+    SIGN_OUTPUT_MSB_2       = 0x0020,
+    SIGN_OUTPUT_COMPARATOR  = 0x0038,
+};
+
+enum OutputMode {
+    OUTPUT_MODE_SINE        = 0x0000,
+    OUTPUT_MODE_TRIANGLE    = 0x0002,
+    OUTPUT_MODE_SQUARE      = 0x0004,
+};
+
+class AD9837
+{
+public:
+    AD9837(PinName mosi, PinName miso, PinName sclk, PinName cs);
+    void setFrequencyWord(unsigned int reg, uint32_t frequency);
+    void setPhaseWord(unsigned int reg, uint32_t phase);
+    void setSignOutput(SignOutput out);
+    void setOutputMode(OutputMode out);
+
+    inline uint32_t computeFrequencyWord(uint32_t frequency) {
+        // This is a manual expansion of (frequency * 2^28) / m_frequency_mhz
+        // Since it doesn't require 64 bit multiplies or divides, it results in
+        // substantially smaller code sizes.
+        uint32_t lval = ((frequency & 0xFF) << 22) / (15625l * m_frequency_mhz);
+        uint32_t mval = ((frequency & 0xFF00) << 14) / (15625l * m_frequency_mhz);
+        uint32_t hval = ((frequency & 0xFF0000) << 6) / (15625l * m_frequency_mhz);
+        return (hval << 16) + (mval << 8) + lval;
+    }
+
+    inline void setFrequency(unsigned char reg, long int frequency) {
+        frequency = this->computeFrequencyWord(frequency);
+        this->setFrequencyWord(reg, frequency);
+    }
+
+    inline void setFrequency(unsigned char reg, float frequency) {
+        this->setFrequencyWord(reg, (frequency * (1l << 28)) / (m_frequency_mhz * 1000000));
+    }
+
+protected:
+    void writeReg(uint16_t value);
+    int m_frequency_mhz;
+    uint16_t m_reg;
+
+private:
+    SPI _spi;
+    DigitalOut _cs;
+};
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