TM4C123AE6PM: Controller not booting up on power cycle

Shrikrishna K said:

We have multiple boards of these configuration, working as intended since couple of years now. Hence we assume circuit to be functional.

Such an assumption may not prove wise - at all times - and under all conditions.     Is it not agreed that for such a board to, 'Perform to Specification' - numerous & potentially wide-ranging requirements must be met?    Yet board failure - even though, especially though - '99 of 100 board-design elements are correct' - may result from (just) a 'single' issue!     Thus - the 'Odds seem heavily stacked' - against any assumption!

What then - to do?

Off the bat - my firm always advises clients to, 'Obtain one of their 'Golden Boards' (NEVER their ONLY one) - and attempt to program that - under the identical conditions which have produced your current, 'Repeated Programming Failures!'     (Such is intended to 'quickly/easily' reveal if your issue is: 'Board or Programming' related - that's VITAL - is it not?)

• Might a different batch, or version, of those (past) pcbs be 'in use' now?
• Might one or several key components have changed?   (different maker, value, marking)
• Might your (past) programming equipment  have changed, been modified, etc.?
• Might your (past) program or programming procedure  have changed, been modified, etc.?
• When was the last time such boards & programming equipment were deployed?   Were any issues noted?    What do your records reveal?
• You note that recently - you've observed 'issues' on three boards!    Have ANY boards accepted your programming - and then worked?   (that's critical - is it not?)
• To eliminate 'Crystal & xtal capacitor' issues
  • Re-Program so that the 'Internal MCU Oscillator' (only) is used ... (or)
  • switch those (xtal/cap) components between (past) 'Known Working Board' and one of those (now) failing.  

• On occasion - such results from the MCU's 'JTAG Signal Lines' being, 'Left to float.'    Thus - when the JTAG Programmer is removed & power later applied - the MCU may become 'disordered.'   Proper pull-up resistors (ideally external {<10K}) will eliminate such issue from consideration.
• As always - under such programming conditions - Power must be adequate and Ground must be solid.   Have both been (recently) tested & verified?

If this list does not fully resolve - at minimum - 'team officials' should have their workload 'lightened.'

Hello Krishna,

To tack onto cb1's advice, were there any modifications made to the software for either board?

Have you tried erasing the flash of the device with LM Flash Programmer before loading the LED blink project so it was in a clean state?

Is there any involvement of a boot loader with these programs?

I also will very strongly second the suggestion from cb1 to try an example project with the internal oscillator as well to see if that works or not.

Thank you for replying.

We have not done any hardware modifications to board.

We have tried erasing Flash using SEGGER JFLASH Lite 6.16j before we program the device using same software.

No boot loader involved in the design.

We are yet to try out using internal oscillator for the program.

Just to reiterate problem, Program/Board works when we load code from Code Composer Studio and run using debugger. But when we power cycle, board not working.

Please help.

Hi,

Thank you for taking time to reply.

We have not changed or modified any programming set up/board.

We have not seen this issue earlier, observed since a week now.

Looks like program getting accepted from controller/board. But not booting up after reset.

We tried swapping crystal caps, did not help.

All JTAG lines (TDI, TMS, TDO, RESET) have 10k ohm pull up to VCC(3.3V), TCK signal has pull down to GND with 1k ohm resistor.

We have measured power and GND and looks good.

We are yet to try with internal oscillator, shall update once we complete.

Since crystal is not oscillating after reset, I suspect there is no drive power from controller (I/Os are in high impedance state?). If it is programmed from CCS and when we hit run command in CCS, crystal starts oscillating and board works.

Please suggest is there anything we are missing out here,

Thank you

Many (most) questions - earlier submitted - remain 'unanswered/unaddressed - possibly unnoted.'     Has all of that (past) 'help' been discounted?

[edit] - this post was generated 'ONE Minute' after your 'focused' reply - thus your reply had, 'Not yet appeared.'

May we note that you appear, 'Not to have tried' our earlier suggestion of, 'Locating & then attempting to program a, 'Known Good (i.e. Programmable) Board!'    Is it not 'vital' that we 'quickly & easily' determine if yours is a 'Board or Programming Issue?     

In addition -  have (any) boards - among your recent board production - 'accepted' the programming operation - and performed (after) power cycle?

It should be noted too - vendor's Ralph asked about, 'Software Changes' - you responded (only) w/'hardware remained static' response.

These 2 issues (ours), 1 from vendor - stand, Key/Critical - (likely) deserve 'attention' - don't you agree?      Your solution likely resides w/in a, 'Process of Selective Elimination' - and such requires that (all) suggestions receive their 'just due.'