In the USB-UART example project, the default baud rate (glUartConfig.baudRate) is set to 115200 in the CyFxUSBUARTAppInit() API.
Since, you are using a CPU-UART DMA Manual Out channel, there won't be any SET_LINE_CODING or GET_LINE_CODING CDC class requests from a Host Application. As a result baud rate will be set to the default 115200.
You need to set the glUartConfig.baudRate field to CY_U3P_UART_BAUDRATE_3M in CyFxUSBUARTAppInit() API to transmit data at 3M baud rate to the device.
Thank you for the reply . I have configured the UART(glUartConfig.baudRate) at 3M baud rate, but still the CPU-UART DMA transmits at 115200 baud rate. So i don't really understand what is going wrong. Is there some other setting which has to be done to make this DMA channel work at 3M baud rate ?