View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0006339 | PicoCoreMX8MP_HW | PowerManagement | public | 2024-07-23 18:13 | 2024-07-23 18:13 |
| Reporter | Keller | Assigned To | |||
| Priority | normal | Severity | minor | Reproducibility | sometimes |
| Status | new | Resolution | open | ||
| Product Version | 1.10 | ||||
| Target Version | 1.20 | ||||
| Summary | 0006339: ONOFF-Button or poweroff command does not switch off power correctly | ||||
| Description | When the board is shut down with the poweroff Linux command or by pressing the ONOFF button, there remains 1.5V on the 3.3V power rail of the base board, This keeps the board in an undefined state between on and off. Remark: This error may also exist on other F&S platforms. | ||||
| Steps To Reproduce | Unplug all ethernet cables. Start the board to Linux, then issue the "poweroff" command (remark: this may need a rather new ATF with a specific SNVS-RTC patch by F&S or the board will reboot immediately). Measure the power on Pin 3 (EN) of U22 on the PicoCoreBBDSI, it will show ~1,5V, which is enough to be recognized as logical high. If the ethernet cable is plugged in and the link is established, the board shuts down correctly and the pin shows 0V. | ||||
| Additional Information | Further investigation has shown that the problem is the SP330E for SERIAL B on the PicoCoreBBDSI. The 3.3V is coupling back the voltage via the R2IN_A and R1IN_B pins 16 and 17 to the CPU. These pins can carry up to 85mA and this seems to be enough to keep the CPU running in this strange state. If the ethernet cable is plugged in, the PHY and its LEDs seem to take enough power so that the voltage drops below the logical low level. Then the power is correctly switched off. Removing the SP330E solves the problem. However there should be a generic solution with the SP330E mounted. Maybe a voltage divider on EN-Pin 3 of U22 can bring the EN pin to low state if the v3.3V rail drops to 1.5V. Then the 3.3V rail should correctly be shut down. However this has to be investigated further. | ||||
