can i take NEO-M8N module to SLEEP mode?

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by keepwalk asked Sep 13
by clive1 edited Sep 13
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0 votes
There are several ways to enter sleep mode...too many to explain here in detail.  Refer to the u-blox M8 Receiver Description and Protocol Specification document, and the application note on power saving modes.
The simplest way to sleep is to maintain V_BCKP while you remove VCC, then re-apply VCC.
by grampy answered Sep 13
by grampy edited Sep 13
okey this is one way, but it his hardwer solution, and can you write me other (forexapmle software solution) way, beacusei dont find this, i only reach 22mA but it is too big, i need microA or 1mA
What response time-to-fix do you expect when the receiver awakens to give you a position fix --- a few seconds, 10 seconds, 30 or more seconds?
What is the quality of the antenna and environment you have and where is it located --- strong signals, OK signals, poor signals?
You state microAmps or 1 mA - is that the sleep current or is it your target for average current over the whole duty cycle?
What is the duty cycle you need---cyclic or on-demand?
cyclic: ---  off for 5 seconds then on again for a position fix?
                --- off for 30 seconds then on again for a position fix?
                ---- off for 30 minutes then on again for a position fix?
on-demand: ---- off for variable time but allowing system to automatically awaken itself every half-hour to provide shortest TTFF?
                             ----  off for variable time but no automatic self-awakening updates?
Are you able to keep V_BCKP on all the time?

The completely user-controlled software method is to use UBX- RXM-PMREQ (section 32.19.3.2 in u-blox M8 Receiver Description and Protocol Specification document) to shutdown the receiver until a transition occurs on the RX pin (or EXTINT 1, EXTINT2, SPI  CS - see command details) .  Your host MCU software can drive its TX out pin (receiver's RX in pin) to zero while the receiver is sleeping, then drive  its TX high to awaken the receiver.   You can use u-center to create the UBX- RXM-PMREQ command string - displayed in hex - which you can include in your host code.
In this mode, the sleep current in V_BCKP is spec'd as "software-off" mode.  If VCC is still high, it may have some non-zero leakage current which you can measure.

Again - read the documents  I referenced so you can make the best decision for your use cases and performance  requirements.
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