Full reset MCU LPC17xx

[lpcware]

Content originally posted in LPCWare by irvind on Thu Nov 22 03:58:18 MST 2012
Hi,

May I know if any way to do a full MCU reset?

I am planning to do a full MCU reset in user application, so MCU can automatic enter IAP bootloader mode.

I have tried NVIC_SystemReset() but it won't work for me. I need a complete MCU reset.

Thanks. :)

[lpcware]

Content originally posted in LPCWare by MikeSimmonds on Thu Dec 05 00:38:25 MST 2013
In another thread (sorry, I can't be bothered to find it -- use search) NXP say SYSRESETREQ *IS* supported on 176x, and I know that it works on 1778 which is used in my design.

However, there *may* be an issue when the ethernet module is involved ...

When the internal reset happens (SYSRESETREQ) there is a low level pulse on the reset out pin -- just the same as with a
power on reset *BUT* it is very short -- IIRC, about 1.25 microseconds.

Most ethernet designs feed the reset out to the PHY chip's reset input, but the reset duration is nowhere near long enough.
Therefore the PHY chip is not reset properly and when you come to initialise the internal ethernet MAC module the 1778
hangs AND looses the debug connection!  There is a footnote in the UM10470 about the lack of a valid ethernet reference
clock freezing the chip when you access the ethernet MAC module.

Hope this is of interrest, Mike

[lpcware]

Content originally posted in LPCWare by LabRat on Wed Dec 04 09:15:19 MST 2013

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Quote: amesonero
According to user manual: "Note: support for SYSRESETREQ is not included in LPC17xx devices"

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Typo or  NVIC_SystemReset() is not working?

[lpcware]

Content originally posted in LPCWare by amesonero on Wed Dec 04 08:55:52 MST 2013
According to user manual: "Note: support for SYSRESETREQ is not included in LPC17xx devices"

[lpcware]

Content originally posted in LPCWare by irvind on Thu Nov 22 18:04:22 MST 2012

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Quote: Zero

NVIC_SystemReset() is resetting this register also :)

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I just realized NVIC_SystemReset() not working properly. Doesn't matter with/without bootloader. :o

I always assumed it "should" work, let me check what's the problem first ;)

thanks :)

[lpcware]

Content originally posted in LPCWare by Ex-Zero on Thu Nov 22 05:45:00 MST 2012

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Quote:

I thought IAP 57 only can use for ISP?

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Of course ;)

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Quote:

I am doing Ethernet bootloader.

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Nice little detail :eek:

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Quote:

When I call NVIC_SystemReset(), MCU hang there I doubt the vector map not completely restore to 0x00.

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So what's your bootloader doing? Relocating vector table start address via VTOR? NVIC_SystemReset() is resetting this register also :)

[lpcware]

Content originally posted in LPCWare by leon_heller on Thu Nov 22 05:39:30 MST 2012
With the LPC2000 chips a full reset was performed by setting the WDT so that it was called immediately. Something like that should work with the LPC17xx.

[lpcware]

Content originally posted in LPCWare by irvind on Thu Nov 22 04:10:27 MST 2012

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Quote: Zero
What's wrong with IAP 57?

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Hi Zero,

I thought IAP 57 only can use for ISP? I am doing Ethernet bootloader. When I call NVIC_SystemReset(), MCU hang there I doubt the vector map not completely restore to 0x00.

Thanks.

[lpcware]

Content originally posted in LPCWare by Ex-Zero on Thu Nov 22 04:05:57 MST 2012

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Quote: irvind
... so MCU can automatic enter IAP bootloader mode...

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What's wrong with IAP 57?