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i.MX6UL UART Tx time-delay option between bytes?

Question asked by Steve Raynesford on Feb 8, 2018
Latest reply on Feb 8, 2018 by Pavel Chubakov

On the i.MX6UL UARTs (RS232 mode), is there any way to add time between transmitted bytes so that the start bit doesn't immediately follow the stop bit? 



I'm working around communicating with a flawed UART in a legacy device on the other end that can't keep up with tight-packed bytes on its UART input (the flaw is documented in that device's errata).  The flaw is independent of bit-rate


We are using DMA for UART transfers and Linux 4.x is the OS.  Currently running at 3Mbps, same issue on 1Mbps.


Using two stop bits doesn't work in our application because it affects the Rx side as well.


Since the two devices are on the same board with no noise or jitter issues, I'm considering slowing down the i.MX6UL UART bit rate to create the illusion in the other device UART of extra time between the stop bit center and the start bit leading edge.  I'm not sure this will create enough extra time, however.




imx6ul uart

uart transmit

uart data transmission