校准是为了满足建立保持时间,那可以选择直接用sysref可以吗?
还有就是,可以正常编程完ADC之后我再发sysref吗?
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您好, 在8.3部分的初始化步骤完整之后,即第14步之后就可以使能SYSREF校准了。
如果您是使用多个ADC12DJ3200,需要保持同步或者确定性延迟的话,需要enable SYSREF校准, 如果只有一片ADC使用,那么使能JESD接口(JESD_EN=1),自动校准就可以了。
8.3 Initialization Set Up
The device and JESD204 interface require a specific startup and alignment sequence. The general order of that sequence is listed in the following steps.
1. Power-up or reset the device.
2. Apply a stable device CLK signal at the desired frequency.
3. Program JESD_EN = 0 to stop the JESD204B state machine and allow setting changes.
4. Program CAL_EN = 0 to stop the calibration state machine and allow setting changes.
5. Program the desired JMODE.
6. Program the desired KM1 value. KM1 = K-1.
7. Program SYNC_SEL as needed. Choose SYNCSE or timestamp differential inputs.
8. Configure device calibration settings as desired. Select foreground or background calibration modes and offset calibration as needed.
9. Program CAL_EN = 1 to enable the calibration state machine.
10. Enable overrange via OVR_EN and adjust settings if desired.
11. Program JESD_EN = 1 to re-start the JESD204B state machine and allow the link to restart.
12. The JESD204B interface operates in response to the applied SYNC signal from the receiver.
13. Program CAL_SOFT_TRIG = 0.
14. Program CAL_SOFT_TRIG = 1 to initiate a calibration.