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No ">" prompt following +CASEND after wakeup from sleep (DRX) #48
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Firmware Revision : 1951B12SIM7080 |
Are you referring to the wake-up reaction time being too long? |
Since there is almost no information in the low power application note I hoped that the wakeup reaction time would be be transparent to the user. After pulling DTR low I expected the modem to execute any serial command after finishing its own internal wakeup sequence. If that is not the case then how does a user determine the earliest time it's safe to interact with the modem (in this case sending a UDP packet via +CASEND)? |
Would it be possible to extend the MinimalModemSleepMode.ino example by doing multiple sleeps? My current sequence is
I just don't know if this is the optimal sequence. |
This issue is stale because it has been open for 30 days with no activity. |
My project is based on MinimalModemNBIOTExample. I am transmitting a ~28 byte UDP datagram every 60s and I want the modem to sleep. I am using DRX as opposed to eDRX or PSM due to future requirements.I added some UDP code (as that is not supported by TinyGSM), set +SCLKC=1 and I'm controlling DTR. The code was compiled with (-DARDUINO_USB_CDC_ON_BOOT=0) and the board is connected to a wall power supply. No UART connection.
In the setup function I acquire NB-IOT, register and open a UDP connection.
Here is my loop function and a modifed TinyGsmSim7080::modemSend :
When I call +CASEND immediately after wakeup there is no ">" prompt in the modem serial stream. I added retries in the modemSend method and with a timeout of 5ms it takes 3 tries to get a ">" prompt. This results in an awake time of ~24ms instead of an ideal ~15ms. When increasing the waitResponse timeout to 50ms I would expect the number of tries to go down but it remains between 1 and 3 tries for an awake time of 65-117ms.
Another workaround is to add a 300ms delay after pulling DTR low but the impact on awake time is unacceptable.
Am I doing anything wrong or have others come across this issue?
Log :
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