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artiq/soc/runtime/dds.c

68 lines
1.9 KiB
C

#include <generated/csr.h>
#include <stdio.h>
#include "rtio.h"
#include "dds.h"
void dds_init(void)
{
int i;
for(i=0;i<8;i++) {
DDS_WRITE(DDS_GPIO, i);
DDS_WRITE(DDS_GPIO, i | (1 << 7));
DDS_WRITE(DDS_GPIO, i);
dds_phase_clear_en(i, 0);
}
}
void dds_phase_clear_en(int channel, int phase_clear_en)
{
DDS_WRITE(0x00, 0x78);
DDS_WRITE(0x01, 0x00);
DDS_WRITE(0x02, phase_clear_en ? 0x40 : 0x00);
DDS_WRITE(0x03, 0x00);
}
/*
* DDS phase modes:
* - continuous: Set sysclk_per_microcycle=0 to disable POW alteration.
* phase_tracking is ignored, set to 0.
* Disable phase accumulator clearing prior to programming.
* - absolute: Set sysclk_per_microcycle to its nominal value
* and phase_tracking=0.
* Enable phase accumulator clearing prior to programming.
* - tracking: Set sysclk_per_microcycle to its nominal value
* and phase_tracking=1.
* Enable phase accumulator clearing prior to programming.
*/
void dds_program(long long int timestamp, int channel,
unsigned int ftw, unsigned int pow, unsigned int sysclk_per_microcycle,
int rt_fud, int phase_tracking)
{
long long int fud_time;
unsigned int phase_time_offset;
rtio_fud_sync();
DDS_WRITE(DDS_GPIO, channel);
DDS_WRITE(DDS_FTW0, ftw & 0xff);
DDS_WRITE(DDS_FTW1, (ftw >> 8) & 0xff);
DDS_WRITE(DDS_FTW2, (ftw >> 16) & 0xff);
DDS_WRITE(DDS_FTW3, (ftw >> 24) & 0xff);
phase_time_offset = phase_tracking ? timestamp : 0;
if(rt_fud)
fud_time = timestamp;
else {
fud_time = rtio_get_counter() + 8000;
/* POW is mod 2**14, so wraparound on negative values is OK */
phase_time_offset -= timestamp - fud_time;
}
pow += phase_time_offset*ftw*sysclk_per_microcycle >> 18;
DDS_WRITE(DDS_POW0, pow & 0xff);
DDS_WRITE(DDS_POW1, (pow >> 8) & 0x3f);
rtio_fud(fud_time);
}