ESP32 Forum

Posted: **Fri Jul 16, 2021 8:54 pm**

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read_RTC_time:
    WRITE_RTC_REG(RTC_CNTL_TIME_UPDATE_REG, RTC_CNTL_TIME_UPDATE_S, 1,1)
wait_RTC_update:
    READ_RTC_REG(RTC_CNTL_TIME_UPDATE_REG, RTC_CNTL_TIME_VALID_S, 1)
    jumpr wait_RTC_update, 0, eq
    READ_RTC_REG(RTC_CNTL_TIME0_REG+2, 0, 16)
    move r1, last_measurement_time
    st r0, r1, 0

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The value I'm getting in R0 looks pretty random. On the other hand, if I do:

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uint32_t* time0 = (uint32_t *) 0x3FF48010;
printf("last_measurement_time: %X, current_time: %X\n", ulp_last_measurement_time & 0xFFFF, (*time0 & 0xFFFF0000) >> 16);

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It seems like I can read the RTC timer fine from the main processor. Current_time makes sense, whereas ulp_last_measurement_time is garbage. What am I doing wrong?

Posted: **Sat Jul 17, 2021 4:45 am**

READ_RTC_REG(RTC_CNTL_TIME0_REG+2, 0, 16)

This doesn't look right. Are you trying to read the upper 16 bits?: READ_RTC_REG(RTC_CNTL_TIME0_REG, 16, 16)

Posted: **Sat Jul 17, 2021 5:20 am**

boarchuz wrote: ↑
Sat Jul 17, 2021 4:45 am

READ_RTC_REG(RTC_CNTL_TIME0_REG+2, 0, 16)
This doesn't look right. Are you trying to read the upper 16 bits?: READ_RTC_REG(RTC_CNTL_TIME0_REG, 16, 16)

Yeah! I got confused by the macro, I ended up just doing

Code: [Select all] [Expand/Collapse]

.set timer_top_16, (0x3FF48014 - DR_REG_RTCCNTL_BASE)/4
REG_RD timer_top_16, 0, 16

And I got it working. Sorry for the trouble, and thank you. I see how what I was doing was wrong now.

ESP32 Forum

esp-32s1 reading RTC timer through ULP, getting garbage.

esp-32s1 reading RTC timer through ULP, getting garbage.

Re: esp-32s1 reading RTC timer through ULP, getting garbage.

Re: esp-32s1 reading RTC timer through ULP, getting garbage.