Do you have any other devices connected to your nRF (electronically, not BLE) and are actively trying to send data to the nRF? If so, detach them and try again.
In one repeatable case I've found it impossible to connect to an nRF51 using SWD via the J-Link when another MCU was communicating using SPI to the nRF51. This happened even if the nRF was totally erased, the SPI chatter just got in the way of SWD working. ymmv All the best Wayne On 22 November 2016 at 17:07, David G. Simmons <[email protected]> wrote: > How are you keeping the board in reset? The only method I've found is to > power the board off, and so far, my timing has not paid off on that front. > > dg > > > On Nov 22, 2016, at 12:04 PM, marko kiiskila <[email protected]> wrote: > > > > Hi, > > > > my trick with this is by keeping the board in reset just until I start > the > > JTAG software. This might take few attempts, but I eventually get lucky > > with timing, and MCU stops before system boots. > > -- > David G. Simmons > (919) 534-5099 > Web <https://davidgs.com/> • Blog <https://davidgs.com/davidgs_blog> • > Linkedin <http://linkedin.com/in/davidgsimmons> • Twitter < > http://twitter.com/TechEvangelist1> • GitHub <http://github.com/davidgs> > /** Message digitally signed for security and authenticity. > * If you cannot read the PGP.sig attachment, please go to > * http://www.gnupg.com/ <http://www.gnupg.com/> Secure your email!!! > * Public key available at keyserver.pgp.com <http://keyserver.pgp.com/> > **/ > ♺ This email uses 100% recycled electrons. Don't blow it by printing! > > There are only 2 hard things in computer science: Cache invalidation, > naming things, and off-by-one errors. > > >
