MK20DX256 flash writting problems below 3 Vdc

[monicae]

When using MK20DX256 at 2.5 Vdc i have flash writting problems, cannot program or erase the microcontroller and generates writting errors using a partition as emulated eeprom.

At 3Vdc it works properly.

Could it be a hardware configuration issue?

[kerryzhou]

Hi monicae,

  To MK20DX256VLQ10 and MK20DX256VMD10, the Flash write voltage range: 1.71 to 3.6 V.

  So your 2.5V should works to the chip.

  When you use the 2.5V, whether that Power supplier is stable enough?

   I mean, do you try any other Power supply which can give the 2.5V? And do you check your VDD whether that voltage is stable or not?

   BTW, before you do the partition, do you erase the whole flash or not?

Best Regards,

Kerry

[monicae]

Hello Kerry, thank you for the answer.

I know that the datasheet stablish a Flash writting voltaje range of 1.71 to 3.6 V, that´s why i´m surprise it doesn´t work properly.

I have tried with precision variable power supply and i have the same results. At 3 V it Works perfectly well in all cases, when using 2.5 V as power supply i have issues erasing and programing the microcontroller, and also writting data in the partition, so i think all the issues are related to the flash writting process.

I tried to power up with 3 V just to reprogram the microcontroller and to safe data into the emulated eeprom and then change the supply to 2.5 V and it Works ok unless i try to access the emulated eeprom.

Kind regards.

[kerryzhou]

Hi monicae

  Could you please give me a photo about your chip, which can seed the detail maskset number on the chip, then I will check more details.

  BTW, when you test the code, do you add the debugger? If yes, what's the debugger voltage you are using?

Best Regards,

Kerry

[monicae]

Hi Kerry, 

Attached the maskset.

For programing and debugging i use PE Micro multilink universal Rev. C, i also attach a photo of it and a screenshot of the debugger configuration.

Hope it helps,

Thank you and regards. 

[kerryzhou]

Hi monicae,

   Thanks for your updated information.

    Now, please help do the following test.

    Write the code, which has these function:

1. Select one flash sector, print some data from that flash sector address.

2. Erase the flash sector, and print some data from that flash sector address.

3. program the flash sector some address, and print the data 

4. use your PE Multilink program the above code to your MK20DX256VLH7 in 3V

   And test the code make sure the code function is working, print use the UART.

5. power off the board, disconnect the debugger PE Mulitlink

6. change your board power supplier to 2.5V, then test the function again, whether that works or not?

  I just want to test without the debugger, so I suggest you download the flash program and erase code to the flash directly, then without the debugger and test it again.

I also checked your chip errata, no flash program voltage limit bugs, so, please do more testing in the chip directly.

BTW, in your board, when you change the voltage, please check the chip VDD pin voltage, whether it is really 2.5V, and no less than 1.71v.

Any updated information, please kindly let me know.

Best Regards,

Kerry

[monicae]

OK Kerry, 

I am now waiting for a cyclone fx of PE micro to come, so i can program directly the device.

I will try both, direct and debugging programmation.

I will inform of the results of the requested test.

Regards.

[kerryzhou]

Hi monicae,

 Ok, any test updated information, just kindly let me know.

Best Regards,

Kerry