08-17-2021, 11:11 AM
(07-28-2021, 03:20 AM)dsimic Wrote: Sounds good, but have you actually tested this hardware fix? This is probably another way to quickly fix the Clusterboard reboot issue, but as you've already described, this fix also renders the reset button inoperable, which may not be desired. Have you checked whether this fix prevents the RTC backup batteries from being discharged when the Clusterboard is powered on? Also, please keep in mind that this fix doesn't prevent the batteries from becoming charged by the VCC_RTC outputs of the AXP803 PMICs on installed SOPine modules. That power path should always be disabled by adding a Schottky barrier diode, regardless of any further modifications, if the RTC backup batteries will be installed.
As a note, I've spent some time debugging some RTC-related issues and journal corruption (see this issue for further information), so having the RTC backup batteries installed would be highly advisable.
Yes, I've removed the diode fix and the resistors connecting the reset circuit to the SOPine modules and the reboot issues are gone.
A proper fix would require the buffer ICs to be replaced by open collector output buffers, which isn't really feasible as a modification. Maybe Pine64 could do a new revision of the board that fixes both the reset circuit and the problems with feeding power back into the RTC battery from the installed modules.