GS6151 datasheet(41/77 Pages) SEMTECH

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GS6151

Final Data Sheet

Rev.4

PDS-060389

August 2015

41 of 77

Semtech

Proprietary & Confidential

www.semtech.com

Figure 4-22: Example Eye Monitor Bitmap

With the eye monitor enabled by setting the HORIZONTAL_EYE_MON_ENABLE bit an

eye scan is started by writing a 1 to the AUTO_SCAN_START bit of the

EYE_MON_SCAN_START register. The eye-scan state machine then scans the eye and

writes a 0 to the AUTO_SCAN_START bit when it completes. The values in the above

registers are then valid if lock was not lost at any point during the eye scan. It is therefore

recommended that the LOCK_LOST_STICKY bit of the STICKY_STATUS register is

cleared before running the eye scan and checking its value after the eye scan is

complete.

After a successful automatic eye scan, the EYE_WIDTH bits hold a value corresponding

to the number of phases that had errors that did not exceed a predefined threshold. This

error threshold is defined as the number of errors that must be observed before the

phase is deemed to be not error-free and is set in the ERROR_THRESHOLD bits of the

EYE_MON_CONTROL_REG_4 register. By default the error threshold is set to 3.

A typical relationship between the EYE_WIDTH result and the input jitter amplitude is

given in Figure 4-22.

GS6151 Arkusz danych(PDF) 41 Page - Semtech Corporation