Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

ilnadi — Sat, 21 Jun 2014 18:54:38 GMT

I have tried Go Studio, nrfjprog --recover, none worked. JLink Commander gives "Could not measure total IR len. TDO is constant high" to each and all of the commands above. Anything else I can try?

PS: I am usign Go Studio 1.17 and Jlink 4.80

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Chris Lovett — Wed, 19 Mar 2014 04:34:29 GMT

I had this same problem until I installed the new version of nRFgo Studio, version 1.16.1 from www.nordicsemi.com/.../nRF51822-Evaluation-Kit

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Ole Morten — Mon, 12 Aug 2013 12:11:14 GMT

I've now sent you a private message. Sorry for the delay.

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Jamie — Tue, 06 Aug 2013 20:38:22 GMT

I assume that the chip remained in this state even when powered off and on again, and if so, if you still have the chip, it could be interesting if you could send it to us. Let me know if you could do this, so I can provide you with an address.

It does remain in the state when disconnecting and connecting a power source, and I do still have the chip.--I would be happy to send it to you.

What's the address, and how do we handle the shipping?

Best, Jamie

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Ole Morten — Tue, 06 Aug 2013 04:36:51 GMT

Unfortunately not. We've had some reports about this, but we've been unable to reproduce it, so we haven't been able to investigate it fully.

I assume that the chip remained in this state even when powered off and on again, and if so, if you still have the chip, it could be interesting if you could send it to us. Let me know if you could do this, so I can provide you with an address.

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Jamie — Mon, 05 Aug 2013 15:11:14 GMT

As I said, as long as you've set a wake-up source before entering system off, this will not happen, so I can't imagine this being a problem that a potential end-user would face.

If you don't have any further questions, I'd be happy if you could accept my initial answer as accepted, if it solved the problem.

In the interest of time, I simply replaced the "locked" chip with a fresh one, and therefore I haven't been able to test your originally posted solution. Since I won't have a chance to test unless this happens again, I will accept your answer and assume it is correct.

That said, I'm still interested to know why nRFgo Studio was unable to wake up the chip to recover it in this particular case, when in the past it has had no trouble doing so after the chip has gone to SYSTEM_OFF with no wakeup source.

Would you be able to provide some further insight into this question, even though I am closing out the original question as answered?

Thank you, Jamie

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Ole Morten — Mon, 05 Aug 2013 05:10:44 GMT

As I said, as long as you've set a wake-up source before entering system off, this will not happen, so I can't imagine this being a problem that a potential end-user would face.

If you don't have any further questions, I'd be happy if you could accept my initial answer as accepted, if it solved the problem.

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Jamie — Fri, 02 Aug 2013 16:28:09 GMT

I was running the stock BLE Heart Rate Service app that comes with the Nordic SDK (which I believe is programmed to go into system off mode after 3 minutes or so of inactivity). The soft device that was installed along with the firmware was the newest one--6.0.0-alpha.

Thanks, Jamie

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Ole Morten — Fri, 02 Aug 2013 06:27:28 GMT

Which firmware were you running on the chip when this happened?

The only way I'm aware that can put the chip in such state is to go into system off without any wakeup sources. There should be no reason to put a device into such state in an actual program, so this isn't really something you should need to think about from an end-user's perspective.

If you have a firmware build that is consistently able to put the chip into such state, I'd be very happy to take a look on it.

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Jamie — Thu, 01 Aug 2013 12:09:55 GMT

Thanks for the reply--I will give your suggestion a try.

We need to understand what caused this state (the chip no longer was running it's firmware even). In the case of production, we need to know what the potential causes of such a situation, how to prevent it, and how to handle it in firmware if it does happen to a customer's device--any suggestions here?

Thanks! Jamie

RE: Cannot recover with NRFgo: "Could not read AHB-AP Id. Could not connect to target."

Ole Morten — Thu, 01 Aug 2013 09:07:52 GMT

No, this error does not mean that the device has been locked in any way. If the recover functionality consistently doesn't work, you can try to open J-Link Commander from the start menu, and write the following:


r
w4 4001e504 2
w4 4001e50c 1
w4 4001e514 1
qc

This basically just does an erase all, by manually writing to the registers, but we've seen previously that sometimes it works to do this manually even when nRFgo Studio is not able to do the same.