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Hot!RN4871 - Stops advertising in low power mode

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RadioFW2018
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2018/12/10 18:17:38 (permalink)
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RN4871 - Stops advertising in low power mode

Has anyone seen an issue where the RN4871 quits advertising in low power mode? The UART also fails to respond when this occurs so something seems hung up.
 
I have not seen this issue when operating in regular mode.
 
Am using FW 1.30.
 
Any insight is appreciated.
post edited by RadioFW2018 - 2018/12/11 12:05:46
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    extronic
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    Re: RN4871 - Stops advertising in low power mode 2018/12/12 03:51:53 (permalink)
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    Please give more details. How do you enter low power mode and what is you module configuration (D command)? Have you tried to modify advertising settings (A command)? How much current does the module consume?
    #2
    RadioFW2018
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    Re: RN4871 - Stops advertising in low power mode 2018/12/12 13:36:23 (permalink)
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    We enable low power mode with the SO,1 command and we enter low power mode by driving the P1_6 line high.
     
    When the module is advertising normally it uses ~300uA once slow advertisement has started after 30 seconds, when the module stops advertising it uses ~2.5mA, similar to connected current.
     
    When the module stops advertising it also does not respond to any commands on the UART bus from the MCU, including the command for it to enter command mode, $$$.
     
    We are using flow control between the module and the MCU
     
    We are also using some non-default advertisement and connection establishment timing settings as well as setting the advertisement payload. 
     
    #3
    xjag
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    Re: RN4871 - Stops advertising in low power mode 2018/12/18 07:40:53 (permalink)
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    When UART communication fails, is there a permanently high level on P3_6 (RTS)?
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    RadioFW2018
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    Re: RN4871 - Stops advertising in low power mode 2018/12/20 15:31:16 (permalink)
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    xjag: I will check and report back. Assuming there was (or wasn't) what would that tell us?
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    xjag
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    Re: RN4871 - Stops advertising in low power mode 2018/12/21 00:11:08 (permalink)
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    It would definitely be very enlightening if you post the result here. If it behaves like that, I know at least that I'm not the only customer where this happens.
    #6
    RadioFW2018
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    Re: RN4871 - Stops advertising in low power mode 2018/12/21 18:05:56 (permalink)
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    xjag: We do not see a permanent high on that pin. However, that doesn't mean we aren't seeing manifestations of the same issue. Do you have a workaround to get around it?
    #7
    extronic
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    Re: RN4871 - Stops advertising in low power mode 2018/12/22 02:53:25 (permalink)
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    RadioFW2018, pin RTS works only if you have hardware flow control enabled, otherwise you won't see anything on this pin. You can enable it with SR,8000. Paste here your module configuration (command D).
     
    Hal a look also on this thread
    https://www.microchip.com/forums/m1078784.aspx
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    RadioFW2018
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    Re: RN4871 - Stops advertising in low power mode 2019/01/03 17:17:35 (permalink)
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    Features = 8080 (Enable Flow Control, Reboot after disconnection)
    Services = 40  (UART Transparent)
    #9
    10code
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    Re: RN4871 - Stops advertising in low power mode 2019/06/27 12:40:23 (permalink)
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    There is an errata (http://ww1.microchip.com/downloads/en/DeviceDoc/80000815A.pdf) for RN4871/BM71 devices.
     
    1. The P1_6 is recommended as a "input" in the ~22 ms delay, until the input state see a low to high transition. Following, the MCU pin is changed from a input to output transmission and set to the desired state(Low power/normal).
    2. The second concern is the 10 uF capacitor on BAT_IN to ground
    #10
    JustPlaneD
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    Re: RN4871 - Stops advertising in low power mode 2019/08/19 11:06:50 (permalink)
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    10code-
    I'm unable to find mention of item #2 in the above post :
    " 2). The second concern is the 10 uF capacitor on BAT_IN to ground"
    in the link address you provided. Perhaps I misunderstood.
    #11
    opkm
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    Re: RN4871 - Stops advertising in low power mode 2019/08/21 11:08:54 (permalink)
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    Hello All,
     
    I've been having the same issue with our device and the RN4871 operating in low power mode.
    At random time the module will simply stop responding and consume current at a rate similar to as when it's connected.
     
    We've discovered though that this glitch seems to happen in a specific batch of 4871:
    • Our device PCB populated with the  RN4871-1833-J7E modules fails consistently at a random time (all failed within roughly 4 minutes of low power operation).
    • Our device PCB populated with the 4871-1904-4DS modules works reliably, no failures so far.
    • Both RN modules were tested on the same PCB to remove the controlling MCU firmware from the equation.
    • Both RN modules are running the RN4871V1.303/18/2018 firmware.
    We were also suggested what 10code indicated above but that did not resolve the issue with the J7E modules.
    • Following release from reset (our device holds the RN4871 in reset to minimize power consumption when module is not in use), the P1_6 low-to-high transition will occur at about 12.7ms to be completed by approx. 13.5ms following release from reset.
    • We noticed that you should wait at least 100ms (not 22ms as suggested) following release from reset before driving P1_6. Driving P1_6 low (to come out of low power mode and communicate with the MCU via UART) prior to that would only partially drive P1_6 low indicating that it's not yet a Hi-z input.  
    • Increasing the BAT_IN bypass capacitor from 10uF to 22uF has no effect.
     
    Peter
     
    #12
    opkm
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    Re: RN4871 - Stops advertising in low power mode 2019/09/09 14:26:24 (permalink)
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    Quick update.
     
    On our recent order we received the RN4871-1734-JVJ modules running the 1.30 firmware version.  The module works reliably. The module date stamp indicates week 34, 2017 making it older the the troublesome  
    RN4871-1833-J7E.
     
    It might be that this issue is limited to only some production batches.
     
    Peter
    #13
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