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CC2530 reset details

dj42901
Expert 1270 points
Other Parts Discussed in Thread: CC2530EMK, CC2530, CC2511

I am working with CC2530EMK's, their internal power on reset works well as far as I can tell. 

But I can find very little information about how the reset works, threshold voltages, timing, that kind of thing.

The CC2530EMK shows no external components connected to the reset line.

Searching the forum for "reset" I found a reference to the CCDebugger user guide which says this:

"The RESETn pin is sensitive to noise and can cause unintended reset of the chip. For reset
lines susceptible to noise, it is recommended to add an external RC filter. Please refer to the
respective SoC datasheet and reference designs for recommended RESET circuitry. The CC
Debugger supports slow transitions on the reset line, using a 2 ms delay between any transition on the
RESET line and other transitions on the DC and/or DD lines."

I am thinking that on my production board I should probably hang a capacitor on that line but I don't know what size or what time constant I would want there.

Does anyone know of any  documents that address this?

Or perhaps a helpful TI person with detailed knowledge of the part can offer some insights?

 

Thanks!

 

 

 

  • 0
    Intellectual 260 points

    Hi dj,

    Yes, anyone may have such question, and I had it also before making my board.

    I have some suggestions to make your board not to waste time like me.

    "But I can find very little information about how the reset works, threshold voltages, timing, that kind of thing.But I can find very little information about how the reset works, threshold voltages, timing, that kind of thing."

    As far as reffering to  SWRU191, timing is not indicated at all.

    I guess you mean to set a Reset SW on your board so you checked the ccDebugger document SWRU197.

    "The RESETn pin is sensitive to noise and can cause unintended reset of the chip. For reset
    lines susceptible to noise, it is recommended to add an external RC filter."

    I've just experienced this sensitive and susceptible problem.

    Firstly I made debug cable (between connecter on my borad and ccDebugger's connecter) about 5cm length but the debugger didn't work at all.

    As shown on p.9 in the SWRU197, I set pull-up registers and capacitor and  made shot the debug cable about 2cm length.

    And it began to work.

    Later I set two 10k pull-up registers to P2_1 and P2_2 respectively and 1000pF capacitor to RESET_N and inserted 3.3k register between Debig port7 and RESET_N.

    Now it works quite stably.

    And as described on p.64 in the SWRU191, cc2530 contains power-on reset, if you need Reset SW on your board, if only you copy the schematic of ccDebugger or Eva board, not to care in detail.

    I hope it would helpful for you.

    Thanks,

    Thycydides



     

     

  • 0 in reply to Thucydides
    TI__Expert 6995 points

    Hi DJ,

    As Thycydides says, adding a simple filter like that can be good if you are concerned about noise on the Reset_N line giving unwanted resets.

    The CC2530 has a power-on reset and a brown out detector circuit that gives reset. They work in combination to hold the device in reset until the internal regulated voltage is high enough for operation, which on a typical device corresponds to a supply voltage just above 1.9V. As soon as the supply voltage drops below the threshold again, the brown out reset will triggerand in combination with the power on reset, it will hold reset all the way down to 0V.

    Peder

  • 0 in reply to Peder
    TI__Prodigy 170 points

    Peder,

    high-profile customer needs to know the reset pushbutton and schematic on CCDebugger circuit works (ie what is in there exactly?

    also they claim to measure a ~20kohm weak pullup to Vdd at the RESET_N input of CC2530, and we want to know what the default input RESET_N input looks like. true CMOS hi-Z? weak pullup and how much?

    Purpose is to put a series resistor to the RESET_N input of CC2530 so that the CCdebugger can over-ride and pull it down when it is connected.

    thanks,  Dave in Bay Area CA

     

    Peder said:

    Hi DJ,

    As Thycydides says, adding a simple filter like that can be good if you are concerned about noise on the Reset_N line giving unwanted resets.

    The CC2530 has a power-on reset and a brown out detector circuit that gives reset. They work in combination to hold the device in reset until the internal regulated voltage is high enough for operation, which on a typical device corresponds to a supply voltage just above 1.9V. As soon as the supply voltage drops below the threshold again, the brown out reset will triggerand in combination with the power on reset, it will hold reset all the way down to 0V.

    Peder

  • 0 in reply to Dave Devries
    TI__Expert 6995 points

    Hi Dave,

    The CCDebugger only contains a CC2511 device which on one end interfaces to the PC driver through USB and on the other hand controls the reset_n, debug clock and debug data on the DUT. I believe it is implemented pretty much exactly as on the SmartRF05EB board.

    Yes, there is a 20K pullup on the Reset_n pin on the CC2530. It is always enabled.

    The CCDebugger will drive the reset_n pin of the CC2530 low to enable debug mode.

    Peder