UART1 as Monitor Port

[fevoldj2]

I am trying to use UART1 as my monitor port but so far I'm only able to receive data on the port. I cannot transmit any data on the port. I have a jumper across the U1 RX Enable header and I have tried putting jumpers on the CTS and RTS headers related to UART1. Is there something else I need to do in order to make this work? It is, of course, already changed in the setup to boot device 1. What am I missing?

[Ridgeglider]

What platform and hardware are you running on? I seem to remember that just becuase you set the boot device to Com1 in the monitor does not mean that you change stdio to Com1. I seem to recall that even if you change the boot port stdio still uses com0 unless you change it in your app too. I'm pretty sure changing the boot device just affects where the boot prompt is sent, and where the "A" input is expected in the 2 sec window at boot to get into the monitor. That said, it's been awhile, and I may stand corrected. Take a look at the SerialToSerial example at C:\nburn\examples\serial\SerialToSerial\main.cpp

[yevgenit]

The boot monitor port is successfully switched between the two UARTs of mod5270 using my custom board and IPSetup.
Check for any activity at 3.3 V TXD line of UART1. Possibly, the issue is caused by the chip of line interface circuit. If the chip has TxEn pin, check the logic level at this pin. If you haven't a scope, pull the CPU module out of the board and verify transfer of static logic levels via the line interface circuit.

I am trying to use UART1 as my monitor port but so far I'm only able to receive data on the port. I cannot transmit any data on the port.

The boot monitor doesn't use CTS and any other handshaking lines.

I have a jumper across the U1 RX Enable header and I have tried putting jumpers on the CTS and RTS headers related to UART1. Is there something else I need to do in order to make this work? It is, of course, already changed in the setup to boot device 1.

[fevoldj2]

So last night I figured out that it works randomly. While probing pins the serial port sometimes starts to respond. I tried a new jumper on the UA1 RX EN header and it's working for now after restarting it. Unplugging the device disables input to the port once again. I'm using a carrier board V1.12. Perhaps this is a known issue?

[pbreed]

Is the serial port on your PC setup to ignore RTS cTS?
If it appears random then it may be the RTS line floating hi or low and turning off the serial transmitter on the PC side.

Paul

[fevoldj2]

I am setup to ignore all H/W flow control. Once the port works it works "forever" (until I unplug the board)

[fevoldj2]

I figured it out. I put a jumper across U1 CTS and it worked fine.

[fevoldj2]

That was a little premature, sorry. It worked until I restarted the NetBurner. Then the por stopped accepting input again =\