JETI telemetry communication protocol & PICAXE

[sierra_uniform]

Hi,

JETI model has published its telemetry communication protocol for the DUPLEX RC components.
http://www.jetimodel.de/data_downloads/117/jeti_telem_protocol_en.pdf
It is using a serial communication with 9 (!) data bits and 2 stop bits and odd parity. My question: Is there a way to use such a protocol with a PICAXE Chip?

SU

 

[hippy]

You could probably only achieve it by bit-banging and that won't be easy or likely even possible at 9600 baud.

Using 9-bit data, odd parity and 2 stop bits is quite unusual. Most micros / UART only cater for 8-bit plus parity or 9-bit without parity.

 

[MFB]

This looks like being different just for the sake of it, with not obvious advantages in return for being incompatible with most microcontrollers.

 

[g6ejd]

Looking at the datagrams, they are not using 9 databits, apart from a seperator byte, in all the examples there are only 8 data bits(0-7), plus an 8th 0 or 1 and the 8th bit is nearly always 1, so in effect it has 3-stop bits, so apart from the separator when bit 8 is 0, you can use a 8-bit receive routine to read the data. You could try ignoring the separator bytes, timing out the reception of that one which would be erroneous.

It looks like a simple/stupid way to make their protocol unique to Jeti, but knowning Jeti that does not surprise me, premium products and prices to match. So to do this you would need to 'bit-bang'- the protocol or find a UART that supported 8-bit plus parity and 2-stop bits and ignore the parity bit, which is always one, who cares if it is 0 or 1

So I think most of the receive protocol can be read as normal using a standard 8-bit receive command.

TX protocol coudl be a little harder to produce the commands at the required baud rate. IF it could be slowed down to say 1200 baud you might find it works hard coding the bit stream.