USART3 Not Found on F411 Nucleo Board

[djsg]

Hi MaJerle,

I want to study your code, but I only have F411 Nucleo board. I found your code for F4 uses UART3 with PD8,9 and Tx/Rx pins. They are not available on my board. Yet, I want to try your code. Any suggestion?

[MaJerle]

• Select your UART and corresponding pins for it. (see Datasheet or CubeMX)
• Find DMA stream/channels that match your UART configuration (for RX and/or TX) (see reference manual)
• Enable UART & GPIO & DMA clocks
• Configure GPIOs with AF for specific UART (see datasheet)
• Change settings for UART2
• Check Interrupt handler names and vectors
• Check correct flags in DMA/UART interrupt routines.

That would be shortly.

[djsg]

I am studying your usart_rx_idle_line_irq code. There are 3 events when you try to copy out Rx buffer: half Rx done, full Rx done, and idle line. I wonder what triggers the idle line event. I didn't get a clear understanding from the reference manual.

Have you tested a case, in which you're expecting to receive a big chunk of data, and you need multiple full Rx events to fully receive? I wonder how not to lose any bytes. In your code, after trigger, MCU directly works on Rx buffer. There is no way to prevent DMA from updating the Rx buffer while MCU is working on it, is it?

[MaJerle]

I propose you read rradme of this repo.

Dma is write only to rx buffer, cpu is read only. So that can work.

[djsg]

that readme is very informative. Thx.