AnsweredAssumed Answered

STM8S: cannot communicate with ROM Bootloader!

Question asked by sighinolfi.andrea on May 11, 2015
Latest reply on May 21, 2015 by WoRo


we are trying to program a STM8S-Discovery, fitted with a STM8S105x6
microcontroller, using the native bootloader (via USART1 pins). We
disconnetted the onboard ST-Link by removing R13-R14 resistor.
We are using a USB-TTL (5 Volt) converter, from wich we took the RX,
TX, GND and VCC signals and connected them to the CN1 connector of the
Discovery board. We are using the Flash Loader Demo software PC, but
we are still not able to communicate and program the STM8S on the
board. We also wrote the proper option byte to enable the bootloader
(via STVP software, please see the attached image), but without any success.
Has the board to stay in reset state after the pressing of the "next"
button of the software PC? Could you tell us please the right
procedure to follow to program via USART (using ROM bootloader)?

Thank you in advance,

best regards.

Note: in the attached image from STVP (read option byte), I noticed that the bootloader option byte value il 0x55 instead of 0x55AA as written in the datasheet.. is it correct anyway?