LSI L64777, Technical Manual

Page: 74 / 124

4-12 Register Descriptions
4.2.3 Register 14
RES Reserved 7
This bit is reserved.
START_MEASUREMENT R/W 6
A transition from 0-to-1 starts a measurement of the byte
clock connected to the ICLK input. MEASUREMENT_
DONE in status register (13) indicates the end of the
measurement. The reset value is 0.
ENABLE_NCO_ LOOP R/W 5
Setting this bit allows a step update in the NCO loop
based on the FIFO fullness. The REF_DUR parameter
can adjust the update frequency. The reset value is 0.
MASK_NCO_IRQ R/W 4
Setting this bit enables the interrupt for the
MEASUREMENT_DONE event. Even in the case of a
disabled interrupt, the status is indicated correctly. The
reset value is 0.
AUTO_ACQUISITION_ON R/W 3
A 1-to-0 transition in this bit starts an internal procedure
to regulate the NCO frequency. The reset value is 0.
Setting this bit to 1 activates the autoacquisition mode.
MASK_ACQ_IRQ R/W 2
If this bit is 1, a transition from 1 to 0 in the
AUTO_ACQUI_RUNNING bit of register 13 causes an
interrupt. The interrupt is visible in the NCO_EVENT bit
of register 12 and clears upon the reading of register 13.
The reset value is 0.
EN_PHASE_LOOP R/W 1
Setting this bit enables the phase acquisition loop, after
Autofrequency Acquisition is completed in the NCO mode
of operation. The reset value is 0.
7 6 5 4 3 2 1 0
RES
START_
MEASURE-
MENT
ENABLE_
NCO_LOOP
MASK_NCO_
IRQ
AUTO_
ACUISITION
_ON
MASK_ACQ_
IRQ
EN_PHASE_
LOOP
FIFO_INT