STM8001J3 - Cannot communicate with the device!

[JAn.1610]

I used ST Visual Programmer to check if soldering's been completed well.

I didn't open any files but just clicked the programming tab (the red arrow one) but the message that it cannot communicate with the device popped up. It still didn't work when I opened '3op16icp.s19' and then programmed.

I had to use I2C, USART, and SWIM so on my PCB I connected USART_TX and SWIM on the same 8 pin, because I found out that if I give time delay before converting 8 pin into USART_TX I can still access it to SWIM pin beforehand.

And I left reset pin unconnected. I worried that if unconnected reset pin might cause problem so I tried it to connect whether ground or VCC, but it didn't work.

Can you tell me what the problem is with my chip?

Thanks