in one of our devices we decided to try ESP8285 directly instead of ESP-12S that we've used so far. Based on the recommended design we've added crystal oscillator and resistors and 2.4GHz chip antenna (with Pi tuning). After turning the module on we send AT+CWMODE=1 and then AT+CWLAP. The module waits for approx. 2.5 s and then returns OK without any +CWLAP message. The same code works with ESP-12S.
What can be the problem? What components could cause the problem? We've tuned the antenna using VNA, we've done that many times in the past and tune antennas for all our devices. The same antenna we use for Bluetooth and works fine there.
Any ideas?