As I said in another thread, I’m trying to make a simple dmx transmitter with a cerberus board and rs485 transceiver as required by the DMX standard http://en.wikipedia.org/wiki/DMX512
As you can see in the frame example, it is not advisable to do this in managed code (someone has done it with a netduino plus and a logical AND chip, but it seems to work only on this board http://forums.netduino.com/index.php?/topic/1501-simple-dmx-transmitter because of specific timing assumptions)
Ok, then let’s do it in RLPLite.
I managed to compile and make RLPLite demo for Hydra working on cerberus. But now, in my abysmal ignorance of the microcontroller world, I ask myself : what now ? And that’s where all hell breaks loose : I’m litteraly lost in the datasheets, code samples and documentations.
My questions :
when I enter RLPLite, all managed code stops, that means, all interrupts are ignored or just postponed ? As the synchronicity of the DMX frame is of the essence, it should not be interrupted while sending the frame, but interrupts should resume normally after this
How to implement a break signal on an usart serial port ? Should I have to revert the serial pins to GPIO output mode for this ? If so, when I go back to serial (to send the actual data) will it be instataneous (because we can’t lose time there)
What’s the correct way to make the timing on STM32F4 ? I don’t understand the sample, which uses an interrupt, I think it is too slow for the μs resolution we need there.
Thanks you very much in advance for any pointers or help on this!