Hi
I have developed a custom board using DA14580-01 QFN40. When I download the DSPS example using uVision v5.13.0.0 and stop the debugging, it does not get detected by DPSP android app. However the same code downloaded to the basic dev board works fine. It even works with another custom board using DA14580-01 WLCSP with similar schematics but different layout. The QFN40 custom board use 3.9nH and WLCSP use 3.3nH RF inductor as advised in documentations.
When I debug step by step over DSPS main loop the two devices go over the same lines of code and stay in main loop. but when I stop the debug only the basic dev board and WLCSP custom board advertise themselves and get detected by DSPS android app. I haven't done impedance matching on either custom boards, but the WLCSP works fine (even without antenna and inductor) while QFN40 board shows no sign of detection even when mobile phone is held very close to it.
When I probe the signals on antenna I can see similar signals on either custom boards but the signal on basic dev board is stronger and cleaner obviously due to impedance matching.
Please help!
Thank you
Wed, 2015-07-15 17:20
#1
DSPS not working on custom board
Keywords:
Device:
Hi behzad,
Can you debug and see if the problematic board goes throught the app_start_adv() function in order to start adveritise? Disable the sleep in order to do that and let us know.
Thanks
它确实通过app_adv_start（）和“//我们现在是可连接的”行。
Similarly for both problematic board and the basic dev board.
but still nothing shows up for the custom board.
Hi behzad,
I think that your problem isn't related to your signal or your antenna, even if you had a bad antenna, the device should be detected by the android app if your are close enough.
What which SDK are you using ? Please try with latest SDK.
Thanks MT_dialog
I use SDK 3.0.10.1
我使用信号分析仪查看了RF信号。当代码传递App_adv_start（）时，有问题的自定义板和dev板开始传输RF信号，因此我怀疑有任何软件问题。
Spectrum analyzer results:
The dev board transmits at center freq of 2.40204 GHz and has a clean spectrum as expected for QPSK modulation with max of -25 dbm but the custom board spectrum is centered at 2.40295 GHz and is not steady and oscillates around the center frequency with errors up to 200KHz and has a very unsteady amplitude with oscillations of 15dbm with max of -10dbm.
Signal Analyzer results:
The results of digital demodulation shows higher magnitude error of average 13 %rms in the custom board while dev board is around 3 %rms.
Demodulated data packets in the custom board are not similar to the dev board. In dev board it starts with all zero bytes and then 10101010 preamble bytes but in custom board bytes are more like 1111000011110000.
In QPSK real-imag quadratures, the transmitted points are all in a clean circle in the dev board however in the custom board it seams the starting points of each advertisement packet start from very low magnitude and then they reach to the expected circle.
I have got similar results from 3 boards with the same design. one with matching circuit, one without and one without any other components populated on the pcb (only DA14580, 16MHz oscillator, 32KHz resonator, LED and the required capacitors and inductor for Vdcdc and Vbat).
Any thoughts what might be wrong?
New findings:
The custom board advertising frequencies have shifted by a +1 MHz. According to the BLE specs, the advertising channels should be 2402, 2426, 2480 MHz but the custom board advertises on 2403, 2427, 2481 MHz instead. When I demodulate the adv packet at these frequencies I can see the preamble 10101010 sequence correctly and the magnitude error is as low as 5 %rms similar to the development board.
相同的代码基本发展广告correct channels but strangely on the custom board the advertisement frequency is wrong by +1 MHz.
I tried changing the CHAN_ZERO_FREQ and CHAN_LAST_FREQ in pll_vcocal_lut.h but it has no effect cause apparently they are not used anywhere in DSPS project.
Please help!
I fixed the problem by designing a new layout with more ground shield around XTAL16M, XTAL32K and around antenna trace.