48 lines
1.5 KiB
C
48 lines
1.5 KiB
C
// This wants to be a "generic" library for ad9833, ad9850 and ad9851.
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// currently, only ad9851 is supported
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#include <stdint.h>
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#include <libopencm3/stm32/gpio.h>
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#include "lib/ad98xx.h"
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#include "lib/gpio_utils.h"
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/* ad98_init will initialize pins, not the whole port.
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* That is, you'll need to
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* rcc_periph_clock_enable(RCC_${dds.gpioport})
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* */
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void ad98_init(ad98_dds dds) {
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gpio_set_mode(dds.gpioport, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL,
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dds.reset | dds.clock | dds.load | dds.data);
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gpio_pulseHigh(dds.gpioport, dds.reset);
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gpio_pulseHigh(dds.gpioport, dds.clock);
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gpio_pulseHigh(dds.gpioport, dds.load);
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}
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static void _send_byte(ad98_dds dds, unsigned char byte) {
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for(int i=0; i<8; i++) { // every bit
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char bit = ((byte >> i) & 1);
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if(bit) {
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gpio_set(dds.gpioport, dds.data);
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} else {
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gpio_clear(dds.gpioport, dds.data);
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}
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gpio_pulseHigh(dds.gpioport, dds.clock);
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}
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}
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const float tunings[AD98_MODELS_NUM] = {AD98_AD9833_TUNING,
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AD98_AD9850_TUNING,
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AD98_AD9851_TUNING};
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void ad98_set_frequency(ad98_dds dds, double frequency) { // requires dds_init to be called before it
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// support AD98_MODEL_AD9850
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uint32_t freqWord;
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freqWord = frequency * tunings[dds.model];
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for(char i=0; i<4; i++) {
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_send_byte(dds, freqWord & 0xFF);
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freqWord >>= 8;
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}
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_send_byte(dds, 0x01);
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gpio_pulseHigh(dds.gpioport, dds.load);
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}
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