Mukhtar Khan

ST-link connectivity issue with some BlueNRG-1 chip

Discussion created by Mukhtar Khan on Apr 7, 2017
Latest reply on May 9, 2017 by Mukhtar Khan

Hello Guys,

                            I'm developing one nice application on BlueNRG-1 chip. I'm facing one issue with some of my boards. I have checked out all possibilities. But problem seems to be with some BlueNRG-1 chips or It gets damaged internally after hand soldering. Not Sure! Please problem details below.

 I have recorded my Laptop screen as well. Please see this link: BlueNRG-1 Chip ST-link Connectivity Issue - YouTube 

 

Overview: Application having simple 16x7 matrix LED display which is drive from ULN2004 & 74HC595 shift register. UL2004 connected directly through controller's IO and shift registers are connected via SPI of controller. Application should work on 12V supply. So there are 5.0 & 3.3V regulator. Shift register 595 chip having 5V & 3.3V provision via 0E resistor. One source at a time possible.
Problem:
1) Display suddenly stops working properly. Appearance of problem is very random.
2) ST-link stop communicating.Sometime it connect when power recycled & automatic mode in use. This problem associate with 1st problem. This problem appear whenever first problem start appearing.
3) Few boards never have this problem but few other boards constantly having this problem.
Info:
1) BlueNRG-1 ST-link utility V1.0.0 is in use.
2)Keil IDE is in use.
3) All peripheral driver taken from ST's website.
4) Referring BlueNRG-1 DK 2.3.0
5) Controller, Balun & 16MHz Crystal arranged from Digikey
6) Other components arranged locally from lamington road mumbai.
7) Using ST-link/V2 debugger
8) 8 boards made.
9) Design reference taken from ST
Observations:
1. Display sometimes works sometimes not. This patterns repeats. Some time display goes completely off.
2. Data comes on row properly which is connected  via ULN2004 to controller port.
3. Columns stops running in expected pattern. Columns are connected via 595.
4. some hardware working fine but is some hardware observing this error.
5. When this problem comes controller stop communicating with BlueNrg -1 ST link.
Test Cases and Result
Sr. No.Test CasesResult
1Controller Ground connection resolved in new PCB versionMicroncontroller Ground connection is proper now.
274HC595 chips replaced with new onesProblem still exist
374HC595 VCC change to 3.3VProblem still exist
474HC595 VCC change to 5.0VProblem still exist but other board continuously working on same situation.
5Power level 3.3V and  5.0V checkedBoth level was 99% correct. Problem exist
6Touch up done to ensure connectivityNo continuity issue
7Possiblity checked in firmware. But everthing is alright. Problem doesn't seems to related with coding otherwise other hardware shoudn't worked properly.
8Hardware properly checkedEverything components and connections are correct.
9595 chips also exchanged from working board.Problem still exist. Problem doesn't seems to be with 595 chips
10ST-link connection checkedother board connecting properly but this board sometime connect sometime doesn't. 90%  of time doesn't connect. Sometime connect when power recycled and when keep in automatic mode.
Possible Causes and Comment
Sr. No.Possible CausesComment
1Hardware Design IssueNot possible as other hardware is working properly on same design and having same PCB version
2Coding IssueNot possible as other hardware is working properly on same code.
3PCB Manufacturing IssueNot possible because PCB manufacturer is proto specialist. Its very rare they have given faulty PCB. Also problem is not static its random. So this should not be the issue.
4Soldering IssueTouch up already done and properly checked. Everything looks fine.
5Fault or errata within controllerAs this is new series and launched in recent year. Possibility is there. But ST would have tested very properly.
6Noise IssueIf noise issue then atleast once problem should come in other working hardware.
7power supply IssuePower supply is proper. This should not be the issue.
8Hand soldering setup Temperature was max 350°C which is  against the recommendation of datasheet. But other hardware made with same setup. So can't say.

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