Customer use ADM1276 to do the POWER_CYCLE command to do loop test, meet CML_FAULT error. The steps of experiment show as below and all of results we find out within 3 cases.
(a) enable alert pin via set CML_ERROR_EN1 of ALERT_1_CONFIGURATION_REGISTER to 1
(b) In first console, keep issue STATUS_WORD command to read data recursively.
(c) In second console, issue POWER_CYCLE command recursively.
(d) At digital oscilloscope we set trigger pin as alert pin(CML_ERROR_EN1). Wait CML_FAULT error and get the waveform
Blue single : CLK
Red single : SDA
Yellow single : BMC Power
Green single : CML error
(1) CML_FAULT error at power-off moment (As attached waveform " CML_FAULT error at power-off moment_1 and CML_FAULT error at power-off moment_2)
(2-1) CML_FAULT error at power-on moment
(2-2) CML_FAULT error at power-on moment
(3)SDA locked and BMC recover SDA. And then BMC send first command to HSC. After first command, we see CML_FAULT error
Please refer attached waveform.
Some questions need help to clearly:
(a) Sometime CML_FAULT error at power-off moment and sometimes CML_FAULT error at power-on moment, Could you give us criterion of judged CML_FAULT??
(b) After power-on, why does the SDA lock to low?? Does CML_FAULT error cause by abnormal I2C single that BMC recover SDA?
Please help to find the root-cause and suggest the solution.