nRF8001: interpreting logic data

RE: nRF8001: interpreting logic data

run_ar — Wed, 23 Aug 2017 07:29:10 GMT

No. on the MOSI line there is no debug byte. So the first packet is the length = 0. The second is what is left in the spi buffer on your controller.

RE: nRF8001: interpreting logic data

Erlend — Tue, 22 Aug 2017 19:33:38 GMT

Thanks for the answer. But what does the second value of MOSI mean then (15, in the original post)? Is Master really sending a packet of 15 bytes?

RE: nRF8001: interpreting logic data

run_ar — Fri, 11 Aug 2017 14:40:37 GMT

The nRF8001 will always send a device started event after power on reset. Usually with a started in setup mode event, but this could also be a standby event, if the configuration was previously writen to OTP. MOSI will use a lenght of 0 as it doesn't have anything to send to the slave in this case. it should use the length field of the received packet to see how many bytes it needs to clock out. What follow after the 0 depends on what is in the MOSI buffer, as long as the length is zero the nRF8001 doesn't care about this. Of course you could clear the whole buffer as well, but it's not needed.

RE: nRF8001: interpreting logic data

Erlend — Sun, 09 Jul 2017 13:13:41 GMT

Doing the logic capture after Uploading the code, the decoded data makes more sense: This time MISO starts with (after the first byte (1)) 4, 129, 2, 0, 2 which is as expected. But MOSI still starts with 0, 15, 180 ... which makes no sense to me.

RE: nRF8001: interpreting logic data

Erlend — Sun, 09 Jul 2017 13:06:57 GMT

Now I see that when I press Reset to start everything again (as I do when I start Logic capture), I get errors in serial output:

Evt Device Started: Standby
Advertising started
Evt Device Started: Standby
HW error: 572
ll_ctrl.s0.c�⸮⸮⸮u1 ���
Advertising started
Evt Device Started: Standby
HW error: 572
ll_ctrl.s0.c�⸮⸮⸮u1 ���
Advertising started
Evt Device Started: Standby
HW error: 572
ll_ctrl.s0.c�⸮⸮⸮u1 ���

ETC

But when I restart the arduino by uploading the program it works like in the original post.

RE: nRF8001: interpreting logic data

Erlend — Sun, 09 Jul 2017 13:01:26 GMT

I would expect the first byte of MOSI to be 5, which is the length of Connect command (15).

This is the serial output:

Arduino setup
Evt Device Started: Setup
Evt Device Started: Standby
Advertising started

I'm also puzzled that Evt Device Started happens with mode = Setup. In the decoding done by Logic (with LSBit first, 8 bits per transfer, CPOL = CPHA = 0, Enable line is active low, and using RDY as enable line) there are no 129 followed by 2 that makes this possible. Decoded logic data: bpaste.net/.../252237975ab0