Programming nRF52 at 1.8V ?

[F.lemke]

Hi All,

We received a new design with a nRF52 powered at 1.8V. We are using a JLINK probe with the SW protocol for the burnin code. When we apply 1.8V we can’t program / burn in our code, even by using your example code. But when we apply the power supply up to 3.3V we can program / burn in our code. Moreover the firmware is running at 1.8V

Does it possible to program the device at 1.8V?

Regards,

[AmbystomaLabs]

No product with cmos gpio can have communications when the sending unit has a significantly different gpio voltage.

Referring to the nRF product spec for gpio you will see that Vinput_low is max 0.3xVdd and Vinput_high is max Vdd (ie, 1.8V). The only way to program it is either run the nRF at 3-3.3V, use a level shifter to convert from 3.3 gpio to 1.8V gpio, or buy a SWD/Jlink with 1.8V logic.

Or, if you take the time to do the ohm's law calculations you could probably come up with a resistance configuration tied to 3.3v to effect a level shifter.

[ovrebekk]

Hi

Which of the J-Link programmers do you have?

Most of them support 1.2-5V programming, and should work fine at 1.8V, but some of the cheaper ones are 3.3V only. The J-Link lite programmers provided with earlier Nordic kits also had this limitation.

For a full overview of the various J-Link variants, please look here.

Best regards
Torbjørn

[F.lemke]

Hi TorbJorn,

Thank for your reply,

Here below is the JLINK programmer specfication www.segger.com/.../

So for you there is no limitation coming from nRF52 device ? I mean we can program the chip even at 1.7V or even below ?

Thanks,

EDIT: Hardware issue, we can program/erase the nRF device down to 1.7V without any problem. However if we go below 1.7V we can't program/erase it. (as specify in the recommended spec)