“I am not sure if I clearly understand your test setup, but there are two things which can cause the module to behave strange;
– RXD-pin, into the module: If your PIC at any stage (during sleep or startup) does not drive the RC1180 with push-pull output, insert a 8k2 (or less) resistor between the modules RXD-pin and VCC. The CMOS input is quite shaky and need
distinct high and low voltages
– Reset: Same issue here, it need to be either well filtered or have low AC-impedance to GND (or VCC). So best solution is to short-circuit the Reset-pin (pin 12) to VCC. This must be removed before any re-flashing of the module, but is no
topic right now
Apart from these, no other issues are noted which can cause the module to malfunction.
Last Update: November 9, 2017