In Some of the power ONs Q2686 is not responding. It is not giving any wind responses. It is not respoding to even AT commads also.
A couple of thoughts/things to check:
- Your power supply (VBatt) is within tolerance (3V3 to 4V2) and you have grounded the shield pins properly?
- Your power supply can supply enough current at start-up/Power on? (see the start-up current waveform in the PTS*)
- The ON/OFF signal is HIGH (greater than 0.8 * VBatt) for more than 1500mS when you are trying to start the module?
- The RESET pin is not stuck LOW? According to the PTS, you shouldn’t be relying on the Reset signal anyway - it’s for emergency use only. The module will be held in reset (i.e. not respond to ANYTHING) as long as the RESET pin is held low.
- Ensure the BOOT pin is OPEN - otherwise the module will start the internal bootloader firmware and be waiting for commands from the DWLWin PC package.
Note that the Boot, Reset and On/Off pins are very close together, so it might also be worth doing a VERY close inspection of your hardware to make sure that there are no manufacturing faults such as solder whiskers between the pads…
*PTS = Product Technical Specifications
Hope this gives you some pointers to try and track down what’s happening on your modules.