Not Getting Serial Connection - Red LED Blinking

[priteshtwr]

Hi All,

I am trying starting my uboot from micro sd card for my device(STM32MP1157D-DK1 .But I am not getting any serial device connection on my host PC and keep on seeing this Red Led Blinking.

[Karl Yamashita]

I have the STM32MP157C-DK2 and the red LED blinks when the USB is connected near the SD card so that's probably normal. Try another USB-C cable.

[PatrickF]

Hi @priteshtwr 

unless you setup something different in your uBoot, the serial console (UART4: TX pin PG11, RX pin PB2)  is available on STLINK micro USB connector.

• CN6 (USB Type-C): supply (no data).
• CN7 (USB Type-C): USB Dual-role data (set as EthernetOverUSB under Linux in our Starter Package). Used also as DFU during Flashload with CubeProgrammer.
• CN11 (USB MicroB); embedded STLink-V2. Used for debugging purpose (SWD) and UART4 console (USB VCP).
• LD4 (bicolor LED) is the STLINK status, stop blinking when STLINK is connected to a PC.
• LD6 (blue LED) light when uBoot is started and later will blink with Linux heartbeat.

Hope this help.

Regards.