Supported Hardware Flags on UART0

[hrsmjjames]

Hi all,

Please forgive me if I've missed another forum post that already includes this information but I've struggled to find anything definitive.

I have a device that requires us to use a 3.3 TTL interface to it. It states in it's documentation: Baud rate – 9600 Data bytes – 8 Parity – None Stop bits - 1 Handshake – None.

I have successfully communicated with it when I use a FTDI USB to TTL Serial Cable (3.3V) but I would like to use one of the PI's UART outputs to do this.

I've gone through the stages of adding to my boot/config.txt

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enable_uart=1                                                                                                          
dtoverlay=pi3-disable-bt  

and if I run raspi-gpio get 14-15 I get:

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GPIO 14: level=1 fsel=4 alt=0 func=TXD0
GPIO 15: level=1 fsel=4 alt=0 func=RXD0

and ls -l shows

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lrwxrwxrwx 1 root root           7 Jul 30 17:10 serial0 -> ttyAMA0

if I use ssty i see the following:

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stty -F /dev/ttyAMA0
speed 9600 baud; line = 0;
-brkint -imaxbel

If I then try and set 1 stop bit

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stty -F /dev/ttyAMA0 9600 cs8 -parenb -cstopb -crtscts -ixon

and then call ssty again I still get:

speed 9600 baud; line = 0;
-brkint -imaxbe

update:
I was missing the -a argumen on stty, however I can see the flags set but I still can't communicate with the device.

So, is the above config possible using the on-board UARTS? Is there something else interfering with them that I might have missed?

Thanks

[hrsmjjames]

I've realised I've made a rookie error that I was missing the -a argument on

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stty -F /dev/ttyAMA0 

so I wasn't receiving the full output however my device is still not working but its fine on the USB one.

Is there anything I could be missing that's interfering with ttyAMA0 or ttyS0?