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Merge branch 'master' of github.com:mossmann/hackrf

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This commit is contained in:
Michael Ossmann
2012-06-01 16:52:10 -06:00
parent 9d035488a3 bd79db5884
commit d9fbecc817
1 changed files with 21 additions and 5 deletions
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26
firmware/common/max2837.c
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@ -136,7 +136,10 @@ void max2837_set_frequency(uint32_t freq)
{
uint8_t band;
uint32_t div_frac;
uint8_t div_int;
uint32_t div_int;
uint32_t div_rem;
uint32_t div_cmp;
int i;
/* Select band. Allow tuning outside specified bands. */
if (freq < 2400000000)
@ -150,12 +153,25 @@ void max2837_set_frequency(uint32_t freq)
LOG("# max2837_set_frequency %ld, band %d\n", freq, band);
/* TODO - frac vs int, compute values */
div_int = 0x12;
div_frac = 0x34567;
/* ASSUME 40MHz PLL. Ratio = F*(4/3)/40,000,000 = F/30,000,000 */
div_int = freq / 30000000;
div_rem = freq % 30000000;
div_frac = 0;
div_cmp = 30000000;
for( i = 0; i < 20; i++) {
div_frac <<= 1;
div_cmp >>= 1;
if (div_rem > div_cmp) {
div_frac |= 0x1;
div_rem -= div_cmp;
}
}
LOG("# int %ld, frac %ld\n", div_int, div_frac);
//
/* Write order matters here, so commit INT and FRAC_HI before
* committing FRAC_LOG, which is the trigger for VCO
* committing FRAC_LO, which is the trigger for VCO
* auto-select. TODO - it's cleaner this way, but it would be
* faster to explicitly commit the registers explicitly so the
* dirty bits aren't scanned twice. */