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©2018 Integrated Device Technology, Inc
September 12, 2018
8A3xxxx Family Programming Guide
DPLL_0.DPLL_REF_MODE
Reference selection configuration.
DPLL_0.DPLL_PHASE_MEASUREMENT_CFG
Measure the phase offset between two inputs using the phase detector. Both single-ended and differential inputs are available for selection.
The coarse phase measurement (in ITDC_UI) is stored in DPLL_PHASE_STATUS and is represented by a 36-bit signed integer. The fine
phase measurement (ITDC_UI/128) is stored in DPLL(x)_FILTER_STATUS and is represented by a 48-bit signed integer.
After selecting the inputs, set the DPLL into Phase Measurement Mode (e.g. pll_mode = 0x5).
Note: In cases where the phase detector factors in one or more periods into its phase measurements (e.g. when the feedback clock drifts and
the phase detector takes one or more cycles to calculate the phase offset), retrigger DPLL_MODE to restart the phase measurement process.
Table 218: DPLL_0.DPLL_REF_MODE Bit Field Locations and Descriptions
Offset
Address
(Hex)
DPLL_0.DPLL_REF_MODE Bit Field Locations
D7
D6
D5
D4
D3
D2
D1
D0
035h
RESERVED[7:4]
MODE[3:0]
DPLL_0.DPLL_REF_MODE Bit Field Descriptions
Bit Field Name
Field Type Default Value
Description
RESERVED
N/A
-
This field must not be modified from the read value
MODE[3:0]
R/W
0
Reference selection mode.
Automatic: DPLL_0.DPLL_REF_PRIORITY_[0:16]
Manual: DPLL_CTRL_0.DPLL_MANU_REF_CFG.MANUAL_REFERENCE
GPIO: GPIO_0.GPIO_MAN_CLK_SEL_0/1/2, GPIO_FUNCTION = 0x7 manual
clock select
Slave: DPLL_0.DPLL_SLAVE_REF_CFG
GPIO_slave: DPLL_0.DPLL_SLAVE_REF_CFG, GPIO_FUNCTION = 0xC
master/slave signal
0 = automatic
1 = manual
2 = GPIO
3 = slave
4 = GPIO_slave
Table 219: DPLL_0.DPLL_PHASE_MEASUREMENT_CFG Bit Field Locations and Descriptions
Offset
Address
(Hex)
DPLL_0.DPLL_PHASE_MEASUREMENT_CFG Bit Field Locations
D7
D6
D5
D4
D3
D2
D1
D0
036h
PFD_FB_CLK_SEL[7:4]
PFD_REF_CLK_SEL[3:0]