eRA400TRS and 9-bit

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eRA400TRS and 9-bit

Postby federicomodina » Tue Sep 02, 2014 3:13 pm

I bought two eRA400TRS because I need to create a wireless communication between several modules.
They normally communicate with each other on a RS485 bus, but I thought I'd remove the physical driver (MAX485) to replace it with RF.
On a model work well because their serial communication protocol is 38.4kbps 8N1 ... it is sufficient to configure the ERA and they work without problems.

On another product modules working at 19.2kbps but with 9 data bits! The frame is composed as follows:

[1aaaaaaaa] [0bbbbbbbb] [0cccccccc] [0dddddddd]

That is, the first "byte" has the 9th bit to 1 and 8 bits for the address (a) and the other "byte" has the 9th bit to 0 and 8 bit of data each (b,c and d).
This method is used to synchronize the communication and I can not change the firmware of the objects.

How do I communicate to the devices that use this type of protocol? Should I use a microprocessor and a RF module that communicates via SPI ... but it's exactly the same configuration of the module eRA400TRS, but with a firmware designed for this function!
I searched on the internet use devices that have this peculiarity, but I've only found one model in China ..... :(

Thank you if someone can give me some help!
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