STM32H747i-disco 10Mhz Uart Rx interrupt problem

[soulshine]

Hello ST experts, i need help about using STM32H747i-disco

I'm testing Uart Tx(DMA)-Rx(Interrupt). My goal is 10Mhz uart tx-rx.

The problem is that i success 750khz, but fail to Rx when baudrate 1Mhz~10Mhz.

I set the disco 480Mhz setting (hw SB setting done for SMPS -> LDO).

Uart8 peripheral clock is 120Mhz(Max). Uart8 Oversampling changed 16 -> 8 sample.

So i can set uart8 baudrate up to 15Mbps.

I connect STM32H747i-disco CN6-D0(PJ9 uart8-rx) to CN6-D1(PJ8 uart8-tx).

So if i run uart8_tx -> uart8_rx will catch.

I have testing uart gpio speed low to very high but it is not work for my case.

Success at 750khz. Fail at >1Mhz.

Need some advise.

Thank you.

[soulshine]

sorry. I wrote wrong expression.

750khz -> 750 kbps

1Mhz~10Mhz -> 1Mbps~10Mbps, 

[Pavel A.]

"Fail" and "not work" don't carry enough details to understand what fails.

Anyway, 10Mbps means ~ 1000 bytes/msec or ~ 1000 interrupts in millisecond, only from that UART. This does not look good.