Could you tell us, what pins are being used for programming. PSoC3 on your custom board ?
Here pins that were used for programming:
I using Miniprog3 to power the device. Vddd=Vddio=Vdda=3.3volt
I think I got the problem. I see that in your case you are not connecting the VTARG pin anywhere. You need to connect the VTARG pin of Miniprog3 to VDDIO1 of PSoC. Miniprog3 measures the voltage on VDDIO to see if the device is powered, since the SWD port pins lye in VDDIO1 quadrant of pins.
Also,ensure that you tie the grounds together!