Hello everybody, i have problem using DMA on UART.

I look in to sample project and it work fine, but it use static string for send with DMA UART, for example ALIGN_32BYTES (uint8_t aTxBuffer[]) = " *****UART_TwoBoards communication based on DMA***** *****UART_TwoBoards communication based on DMA***** *****UART_TwoBoards communication based on DMA***** ";

it use "text", but when i try use dynamic data, or try change aTxBuffer then no result, DMA with UART always send zeros (000000....). Question, how can i send any dynamic data with UART and DMA. For now i use HAL_UART_Transmit_IT and it work fine, but i need DMA (HAL_UART_Transmit_DMA ). Thanks.