Oh! I have mistake.Maybe you must find 'HAL_UART_MspInit' function In second method.

You can change the DMA data width in 'ioc' file or 'stm32f3xx_hal_msp.c' file.In my case is use DMA for record ADC value. But now am i explain how change data width. So i think not many difference.1.Change in .ioc fileI think maybe you aleady added D...