I’m evaluating processors for an upcoming project, and the RCM-6750 is one I am considering.
I’ve got the data sheets, DC downloaded, and looked at much of this forum; all good data, but I still have a few questions.
First, a quick description of the project hardware. It will send and receive DMX-512, (async serial @ 250k), have one SPI interface to the main touchscreen controller, and also have another software-selectable serial connection:
#1: 1-Mbit rate, Manchester-encoded HDLC data stream.
#2: 100k async serial (yes, that’s the correct baud rate).
#3: 230.4k, FM0 encoded async serial
#4: 115.2k async serial
#5: 19.2k async serial.
#1-3 would need 2 receive (for data logging) and one transmit in the initial phase, then just single Tx/Rx.
Quite the variety. I was originally considering using a dsPic’s PMP port tied to a Z16C35 processor, and that’s still plan B…
So far, it looks do-able on the RCM6750 IF I change the oscillator to a 16 MHZ part instead of 25MHz. 25Mhz just doesn’t divide to get me the exact 16MHz clock I need for #1’s HDLC.
From what I can see, it’s either both TX/RX external clocks, or both internal. The Rx clock would be encoded in the Manchester stream; I’d need to generate the TX.
The other thing I’m concerned about is the instruction time. There seems to be a lot of overhead in the DC compiler, and with instructions taking upwards of 10 clocks, even at 200 MHz that starts to add up in hardware timing.
And finally…is this going to be an viable choice? Digi hasn’t done much with this since they purchased it. Is there an EOL in the stars for this line?
I’m just trying to make an informed choice. This is my top choice at the moment, but I’m not super strong on C as of yet. maybe it’s a good time to learn!
Thanks for the input,