STM32f105RCT6 - faulty MCUs?

[raf_gc]

Posted on June 07, 2010 at 13:31

STM32f105RCT6 - faulty MCUs?

#11011

[raptorhal2]

Posted on May 17, 2011 at 13:54

Lets see if we can isolate the problem to one of:

Faulty MCU Faulty board Faulty code Faulty test. I have the STM32F105RCT6 device on two different boards. On both boards, Vss3 is connected to board ground and PA14 to the JTAG clock signal. PA2 is connected as USART2 tx on one board, and as ADC1 IN2 on the other. Ground, JTAG, USART2 and ADC all function correctly. The chip markings are: 9905 VC MYS 99 923 Check your chip version markings and compare with the device errata sheet on the STM web site for published known problems. Use a 10 power magnifying glass and inspect your installation for shorts, and for pins not soldered to the trace, and other fabrication problems. Have someone with a critical attitude check the code for something you might have missed. If it is someone else's code, review it as if someone is out to get you. Then be forgiving if you find errors. Have someone with a good electronics background review your testing and the PCB design to make sure your meter usage is correct, and that you don't have a faulty board design that is destroying the MCU. Welcome to the fun world of integration testing. Cheers, Hal

[John F.]

Posted on May 17, 2011 at 13:54

''Why there is short between Vdd2,3 to PA2 and PB14 nad between PA2 and PB14 and this doesn't happen on the any other pins?''

It just doesn't seem likely that the part is faulty (unless it's been damaged following manufacturer) and certainly less likely that a whole batch is faulty. It seems more likely that either the part has been damaged in use or that you have mis-identified the pins or that your measurement is somehow wrong. If you are convinced the parts you have been supplied are faulty then you must contact ST through your distributor. Do the parts work in circuit? Do they work if you just power the microcontroller with the rest of your circuit disconnected? Can you toggle PA2 and PB14 separately? What is the power consumption? A short from GPIO to Vdd should show up! These would be better tests of the part than multimeter measurements. John F.