device start-up issue. any suggestions ?

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Anonymous
Not applicable

Hi all,

   

I am facing a bring-up issue with a custom designed electronic assembly that is based on a CY5668LTI-LP014 IC in QFN-68.

   

Here is a quick description of the psoc project:

   

* The f/w program is a stand-alone application, it implements a basic configuration of a few digital input and output pins.

   

* The psoc project operates with internal ILO and IMO, no use of the crystal oscillators. It also does not make use of the internal boost converter since the IC is powered from externally regulated voltage source.

   

* All analog, logic core, i/o voltages seem OK and are @3.3V with low noise ~50mVpp. 

   

* All analog and digital voltages and which are generated by the IC seem correct level ~0.9V, negligible noise and are externally de-coupled.

   

* Single H/W reset asserts/de-asserts as intended during device programming and user interaction, via dedicated XRESn pin (no use of 2nd optional pin).

   

* Device Flash NVM successfully programmed/verified using JTAG in self-powered mode. 

   

Despite this, the firmware program fails to start-up and activate/toggle the digital i/o ports of the IC. For narrowing down the issue i have also connected the internal ILO (100kHZ) to one of the digital ports; the port assumes the correct start-up level (high or low as configured in the psoc project schematic) but the expected AC signal of the ILO is not appearing after power-up. 

   

My conclusion is that something is interfering with internal ILO to start-up and prevents the program code to be copied form flash and execute.

   

My questions are:

   

Are there any configuration settings/trims which might affect the operation of the ILO, or brown-out detectors and which can be manipulated in the psoc project or fitter settings ?

   

Are there are any techniques which i can use to gain any insights as to what is preventing the embedded MCU to start up upon power-on and hardware reset ?

   

Thank you

   

Kostas

   

PS: Attached is the project schematic

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6 Replies
Bob_Marlowe
Level 10
Level 10
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Debugging your project could help. Can you try to get hands on a miniprog3 which would enable you to check whether the chip starts up correctly.

   

 

   

Bob

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Anonymous
Not applicable

Hi Bob,

   

thanks for your reply. I do use miniprog3 to program the flash via JTAG but haven't not used it for debugging the internal MCU. What are the avaialbel hooks that I can use to check the correctness of the start-up sequence ?

   

Regards,

   

Kostas

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Bob_Marlowe
Level 10
Level 10
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When using the miniprog to debug, the program will stop at the very first line of your main(). If that is not reached, the initialization phase will loop at an error. where you may stop it and investigate.

   

Miniprog can deliver 3.3V power, use 5 pin interface: SDA, SCL, XRES, GND and VTARG.

   

 

   

Bob

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HeLi_263931
Level 8
Level 8
100 solutions authored 50 solutions authored 25 solutions authored

Also, look at AN61290 (HW design considerations) and AN57821 (Mixed-signal PCB considerations) more information how to lay out your board - maybe it has some clues what went wrong.

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Anonymous
Not applicable

Thank you for you reply hli.

   

In AN577821 there is an example schematic in which all pins associated with the internal boost regulator are tied to the ground. Maybe these if left floating externally can cause instability to ILO or its internal power supply. I will try to tie them to VSS and will let you know if the issue improves.

   

Kostas

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Anonymous
Not applicable

The issue has been resolved, it was caused by the external pins of the internal boost converter and which had been left floating in the schematic.

   

Thank you all for your suggestions !

   

Kostas

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