xDot Analog inputs not restored after sleep

[Andrew Lindsay]

Hi,

I have a device reading analog inputs and have seen that they are not being restored after waking from a sleep. This is the normal sleep not the deep sleep.

I thought it was my code but tried this with the ota_example and it shows the same issue. Is latest libmDot for xDot, not development branch with correct mbed-os 5.4.7 for this library release.

[INFO] version —————— 3.0.0-mbed144
[INFO] current channel plan —– EU868

The code is there to read the LUX sensor on the xDot DK but I didnt use this, the alternative for mDot was to use the analog input. To reproduce, I forced the example ota_example.cpp to use AnalogIn

//#if defined(TARGET_XDOT_L151CC)
//I2C i2c(I2C_SDA, I2C_SCL);
//ISL29011 lux(i2c);
//#else
AnalogIn lux(PB_0);
//#endif

Where the sensor was read, this was also updated.

The first time after a successful join I see in the output:

[INFO] RxDone 33 bytes RSSI: -58 dB SNR: 77 cB
[INFO] Network joined
[INFO] Packet RSSI: -58 dB SNR: 77 cB
[INFO] light: 62143 [0xF2BF]
[INFO] Preparing frame
[INFO] Configure radio for TX
[INFO] Configure radio for TX
[INFO] Rx Window 1
[INFO] Rx Window 2
[INFO] successfully sent data to gateway
[INFO] sleeping 10s or until interrupt on WAKE pin
[INFO] application will resume after waking up
[INFO] entering sleep (stop) mode 00000037

Now the next time I see:

[WARNING] Fixed the TIM_MST prescaler
[INFO] light: 0 [0x0000]
[INFO] Preparing frame
[INFO] Configure radio for TX
[INFO] Configure radio for TX
[INFO] Rx Window 1
[INFO] Rx Window 2
[INFO] successfully sent data to gateway
[INFO] sleeping 10s or until interrupt on WAKE pin
[INFO] application will resume after waking up
[INFO] entering sleep (stop) mode 00000037

The Light value is now 0.
I am using

sleep_wake_rtc_or_interrupt(deep_sleep);

with a deep_sleep value of false.

If I update the function sleep_wake_rtc_or_interrupt to replace the actual sleep with a wait then analog port is read correctly each time.

// dot->sleep(delay_s, mDot::RTC_ALARM_OR_INTERRUPT, deepsleep);
wait(delay_s);

Is there an issue that the analog inputs are not being restored correctly?

Regards

Andrew

[Andrew Lindsay]

Seems this issue has already been reported on developer.mbed.org forum with a workaround that seems to work.

https://developer.mbed.org/questions/78300/xDot-ADC-problem-when-coming-out-of-slee/

Thanks

Andrew

[Author]

Posts