How accurate is the eTPU UARTs?

[v8dave]

Hi all,

I am trying to get a USB host controller, VNC1L from Vinculum working with an eTPU UART running at 115200 bps.

There is no reply from the VNC1L and as yet I am not sure where the fault is. The device is correctly wired etc.

When I hook up the logic analyser to the TXD and RXD lines and set this to decode the UART signal, it reports a FRAME ERROR for 115200 bps. The data is nice and clean on the analyser and the scope. There is no noise on the supply to the device and the oscillator is running at 12Mhz as it should be.

Have anyone else had success with the eTPU for UART use and noticed any issues with timing?

Dave...

[Ridgeglider]

I use 4 parallel eTPU Uarts simultaneously in addition to the 3 standard UARTS. They seem to work well, although most are running at less than 19,200 baud for relatively slow "blurt & stop" NMEA string parsing, not long-duration, fast transfers. Most support both Tx and Rx w/o hardware handshake. I seem to remember Larry commenting that the eTPU Uarts might not happily support higher baud rates and so I've tried to use the on-board uarts for either high speed, or for half-duplex RS485 use.

[v8dave]

Thanks RG,

I think the issue I have is with the device itself not responding. More hardware debugging to do!!

Cheers,
Dave...