Hi, I would connect my EvoPrimer STM32F107V by using USART TX,RX on connector to a DB9 RS232 to communicate with a Hyperterminal program for a PC. To do this I used the demo Serial_USART_2
Did you adapt the signal voltage ? The Primer Rx/Tx are 3V/0V signals, and PC signals are +12/-12V. You need a TTL/RS232 adapter. Take a look at the web to purchase it or design it (with a MAX232 for example).