ZHCSCX2E January 2014 – October 2017 LM15851
PRODUCTION DATA.
31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 |
NCO_FREQ_x | |||||||
R/W-0xC0h | |||||||
23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 |
NCO_FREQ_x | |||||||
R/W-0x00h | |||||||
15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 |
NCO_FREQ_x | |||||||
R/W-0x00h | |||||||
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
NCO_FREQ_x | |||||||
R/W-0x00h |
Bit | Field | Type | Reset | Description |
---|---|---|---|---|
31-0 | NCO_FREQ_x | R/W | 0xC0000000h | Changing this register after the JESD204B interface is running results in non-deterministic NCO phase. If deterministic phase is required, the JESD204B interface must be re-initialized after changing this register. The NCO frequency (ƒ(NCO)) is: Equation 12. ƒ(NCO) = NCO_FREQ_x × 2–32 × ƒS
where
This register can be interpreted as signed or unsigned. Use this equation to determine the value to program: Equation 13. NCO_FREQ_x = 232 × ƒ(NCO) / ƒS
If the equation does not result in an integer value, you must choose an alternate frequency step (ƒ(STEP) ) and program the NCO_RDIV register. Then use one of the following equations to compute NCO_FREQ_x: Equation 14. NCO_FREQ_x = round(232 × ƒ(NCO) / ƒS)
Equation 15. NCO_FREQ_x = round(225 × ƒ(NCO) / ƒ(STEP) / NCO_RDIV)
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