RC schematics

[neoshaakti]

Does anyone have the schematics for a 2007 RC, or a 2004/2005 RC?
if not, do you know where I can get one?

[kevin.li.rit]

Not 100% on this but I don't think they make that available. What do you need it for?

[ebarker]

I really doubt it is available but it isn't even really necessary. Basically if you take the processor which is well known and fan out all the connections and put some protection on the i/o lines and some power supply regulation you will have 90% of it.

That is basically the way it is with high integration microcontrollers.

What are you trying to do ?

[RyanCahoon]

Not sure if this is what you need, but it should be a start.

The venerable Kevin Watson has posted a mapping of RC ports to the pins of the PICs inside it. Won't give you any information about the power connections or suchlike, but most if not all of the data connections are included.

Hope this helps,
--Ryan

[Al Skierkiewicz]

Neo,
As far as I know, this is one thing IFI hasn't released. On their website you can find equivalent input circuitry for the control lines if that would help. You can guess at what is inside though. A microproc, a bunch of A to D convertors with input filtering and conditioning, some memory, a bunch of PWM generators, relay drivers and serial port controllers and a power supply.

[afi419]

You can always open up the RC and take a look inside, I'm guessing the warranty is already void on the old ones.

[neoshaakti]

oh, I was just curious to see how exactly the digital inputs are transfered to the radio which is controlled by the joysticks from the OI

hmm I guess I could open one up...but sadly we dont have any spares lying around...our only RC is on our robot

[ebarker]

Originally Posted by neoshaakti

oh, I was just curious to see how exactly the digital inputs are transfered to the radio which is controlled by the joysticks from the OI

hmm I guess I could open one up...but sadly we dont have any spares lying around...our only RC is on our robot

Forget the schematics !! All the heavy lifting is done in the processor.

a) Basically the digital pins go straight into the processor.

b) the software reads the pins and stuffs the values into a telemetry packet

c) the packet goes out the processor on a serial I/O uart which is connected to a RS485 driver which goes to the radio which goes to an antenna which goes to the 'ether' to the OI - > antenna - > radio -> serial I/O uart on the OI where the OI processor unpacks the telemetry packet and extracts out the field with the values and places it on a display or something at the rc.

d) the same process goes the reverse direction from the OI to the RC.

You just want really understand the micro architecture, from the Microchip data sheet, and the telemetry format, from the FRC code base.

The schematic is trivial, relatively speaking.

[neoshaakti]

what is a RS485 driver ?
and this may sounds dumb, but does the power, ground and signal travel on the PCB itself?
and, do you recommend any literature that can teach me about microcontrollers? thank you

[Kevin Watson]

Originally Posted by neoshaakti

what is a RS485 driver ?
and this may sounds dumb, but does the power, ground and signal travel on the PCB itself?
and, do you recommend any literature that can teach me about microcontrollers? thank you

Actually, I believe it's RS422/EIA422.

-Kevin

[ebarker]

Originally Posted by Kevin Watson

Actually, I believe it's RS422/EIA422.

-Kevin

Oops, my bad. I meant to say RS422 or RS422/EIA422 to be picky.

For our listening audience RS485 is a close cousin. You can use a pair of RS422 circuits to implement a 'full-duplex' channel or use RS485 to implement a 'half-duplex' channel.

Since we are here:

RS232 is single ended, RS422 is differential. What does that get you? long distances and noise immunity. Very useful in the electrically noisy environment of a student built robot.

[Ziaholic]

Actually, the RS485 and RS422 standards are very similar protocols, but while RS422 has just a pair of devices on the bus (sender and receiver), an RS485 interface can support more than 2 devices on the bus ... so when a 485 device isn't sending, it puts its outputs into a Hi-Z state.