Nicolas Farabegoli / AD9837

Library for interfacing with AD9837, generate Sine/Triangular/Square wave

AD9837.h@0:fdfd54fe27dc, 2015-06-30 (annotated)

Committer:
nicolas97
Date:
Tue Jun 30 08:25:56 2015 +0000
Revision:
0:fdfd54fe27dc
Library to interface with AD9837 (function generator)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nicolas97 0:fdfd54fe27dc 1 #include "mbed.h"
nicolas97 0:fdfd54fe27dc 2
nicolas97 0:fdfd54fe27dc 3 enum SignOutput {
nicolas97 0:fdfd54fe27dc 4 SIGN_OUTPUT_NONE = 0x0000,
nicolas97 0:fdfd54fe27dc 5 SIGN_OUTPUT_MSB = 0x0028,
nicolas97 0:fdfd54fe27dc 6 SIGN_OUTPUT_MSB_2 = 0x0020,
nicolas97 0:fdfd54fe27dc 7 SIGN_OUTPUT_COMPARATOR = 0x0038,
nicolas97 0:fdfd54fe27dc 8 };
nicolas97 0:fdfd54fe27dc 9
nicolas97 0:fdfd54fe27dc 10 enum OutputMode {
nicolas97 0:fdfd54fe27dc 11 OUTPUT_MODE_SINE = 0x0000,
nicolas97 0:fdfd54fe27dc 12 OUTPUT_MODE_TRIANGLE = 0x0002,
nicolas97 0:fdfd54fe27dc 13 OUTPUT_MODE_SQUARE = 0x0004,
nicolas97 0:fdfd54fe27dc 14 };
nicolas97 0:fdfd54fe27dc 15
nicolas97 0:fdfd54fe27dc 16 class AD9837
nicolas97 0:fdfd54fe27dc 17 {
nicolas97 0:fdfd54fe27dc 18 public:
nicolas97 0:fdfd54fe27dc 19 AD9837(PinName mosi, PinName miso, PinName sclk, PinName cs);
nicolas97 0:fdfd54fe27dc 20 void setFrequencyWord(unsigned int reg, uint32_t frequency);
nicolas97 0:fdfd54fe27dc 21 void setPhaseWord(unsigned int reg, uint32_t phase);
nicolas97 0:fdfd54fe27dc 22 void setSignOutput(SignOutput out);
nicolas97 0:fdfd54fe27dc 23 void setOutputMode(OutputMode out);
nicolas97 0:fdfd54fe27dc 24
nicolas97 0:fdfd54fe27dc 25 inline uint32_t computeFrequencyWord(uint32_t frequency) {
nicolas97 0:fdfd54fe27dc 26 // This is a manual expansion of (frequency * 2^28) / m_frequency_mhz
nicolas97 0:fdfd54fe27dc 27 // Since it doesn't require 64 bit multiplies or divides, it results in
nicolas97 0:fdfd54fe27dc 28 // substantially smaller code sizes.
nicolas97 0:fdfd54fe27dc 29 uint32_t lval = ((frequency & 0xFF) << 22) / (15625l * m_frequency_mhz);
nicolas97 0:fdfd54fe27dc 30 uint32_t mval = ((frequency & 0xFF00) << 14) / (15625l * m_frequency_mhz);
nicolas97 0:fdfd54fe27dc 31 uint32_t hval = ((frequency & 0xFF0000) << 6) / (15625l * m_frequency_mhz);
nicolas97 0:fdfd54fe27dc 32 return (hval << 16) + (mval << 8) + lval;
nicolas97 0:fdfd54fe27dc 33 }
nicolas97 0:fdfd54fe27dc 34
nicolas97 0:fdfd54fe27dc 35 inline void setFrequency(unsigned char reg, long int frequency) {
nicolas97 0:fdfd54fe27dc 36 frequency = this->computeFrequencyWord(frequency);
nicolas97 0:fdfd54fe27dc 37 this->setFrequencyWord(reg, frequency);
nicolas97 0:fdfd54fe27dc 38 }
nicolas97 0:fdfd54fe27dc 39
nicolas97 0:fdfd54fe27dc 40 inline void setFrequency(unsigned char reg, float frequency) {
nicolas97 0:fdfd54fe27dc 41 this->setFrequencyWord(reg, (frequency * (1l << 28)) / (m_frequency_mhz * 1000000));
nicolas97 0:fdfd54fe27dc 42 }
nicolas97 0:fdfd54fe27dc 43
nicolas97 0:fdfd54fe27dc 44 protected:
nicolas97 0:fdfd54fe27dc 45 void writeReg(uint16_t value);
nicolas97 0:fdfd54fe27dc 46 int m_frequency_mhz;
nicolas97 0:fdfd54fe27dc 47 uint16_t m_reg;
nicolas97 0:fdfd54fe27dc 48
nicolas97 0:fdfd54fe27dc 49 private:
nicolas97 0:fdfd54fe27dc 50 SPI _spi;
nicolas97 0:fdfd54fe27dc 51 DigitalOut _cs;
nicolas97 0:fdfd54fe27dc 52 };