Alarm2 of AM335x RTC_SS is not functional in beaglebone black

Da Shi Cao

Other Parts Discussed in Thread: AM3358

I try to shutdown the power output of TSP65217C from AM3358. As I understood it, the RTC sub-module of AM3358 has its PMIC_POWER_EN connected to TPS65217C PWR_EN. Anyway the issue is that the RTC alarm2 will not fire when time reached, no interrupts can be seen from RTC Status Reg. In fact even the mask of alarm2 interrupt cannot be enabled in RTC Interrupt Reg. I'm using a customized Linux kernel 3.18

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Da Shi Cao said:
I'm using a customized Linux kernel 3.18

This Linux version is not supported by TI. The latest Linux SDK for AM335X can be downloaded here: http://software-dl.ti.com/processor-sw/esd/PROCESSOR-SDK-LINUX-AM335X/latest/index_FDS.html

0 Da Shi Cao over 9 years ago in reply to Biser Gatchev-XID

Prodigy 20 points

Maybe the kerenel it is not supported, but my issue seems unrelated to kernel version. The ALARM2 interrupt mask, as specified in AM335x reference guide, cannot be enabled (set to 1) in RTC Interrupt Register. But the alarm and the timer interrupt can be enabled and/or cleared. It is even unclear if alarm2 expiration will generate one interrupt. I guess an IT will be generated as there is a bit (4) in the status register, which is described as "Indicates that an alarm2 interrupt has been generated.Software needs to wait 31 us before it clears this status to allow pmic_pwr_enable 1->0 transition." Somehow I never saw the interrupt, so the power remains on.

0 Biser Gatchev-XID over 9 years ago in reply to Da Shi Cao

TI__Guru**** 393215 points

I have asked the RTC experts to comment. Feedback will be posted directly here when available.

Processors

Processors forum

Alarm2 of AM335x RTC_SS is not functional in beaglebone black