Buttonless DFU bootloader working in nrf51-DK, but not on nrf51822

RE: Buttonless DFU bootloader working in nrf51-DK, but not on nrf51822

Vidar Berg — Tue, 29 Sep 2020 09:18:57 GMT

Hi Ricardo,

It is correct to set the RAM size to 0x1A30 as you did initially. I reduced that size by 0x80 bytes to leave room for a "no-init" section at the end of RAM because I forgot that it's not used by the bootloader anylonger (used up until SDK 11).

Calculation: RAM_SIZE = total RAM size - ram start = 0x4000 - 0x25d0 = 0x1a30

RE: Buttonless DFU bootloader working in nrf51-DK, but not on nrf51822

Ricardo Rodrigues — Mon, 28 Sep 2020 13:48:20 GMT

Hi Vidar,

In the meantime I had already fixed this by trial and error, but without really understanding what I was doing.

After setting RAM_PH_SIZE to 0x4000, I was following the messages in the logs and ended up using

RAM_START=0x200025d0
RAM_SIZE=0x1A20

although the log messages were saying that RAM_START should be 0x200025e0, it would then give an error saying that ram start should be changed from 0x200025e0 to 0x200025e0 (yes, that's right - the values was already set as suggested and then there was a suggestion to change to the same value).

So then I tried with 0x200025e0 and it worked, but my confidence level on this "solution" wasn't great, and couldn't figure out how to calculate these values properly.

I tried the values from your suggestion and it works without complaints, so I will use those instead of mine.

Would be interesting though if you could explain how you calculated these values?

Best regards,

Ricardo

RE: Buttonless DFU bootloader working in nrf51-DK, but not on nrf51822

Vidar Berg — Mon, 28 Sep 2020 13:27:02 GMT

Hello Ricardo,

The problem is the RAM setting you said. Try using the settings shown in the screenshot below. Those should work with the xxAA variant.

Best regards,

Vidar