Noob question <SOLVED>

jknilinux

Hello,

I am working on a laptop-based robot, and I would like to interface the propeller to it for sensor/motor control. Could I have a setup where my laptop can just tell the propeller "Have cog 1 loop until this condition, and let me know when it is reached. Now make cog 2 drive both motors forward until I tell it to stop." etc... What possibilities are out of the question? Thanks!

Post Edited (jknilinux) : 3/18/2008 8:58:29 PM GMT

Rayman

Easiest way is to use Fullduplexserial object on Prop side and Hyperterminal on laptop side.

hippy

There's also the capability to use the Propeller as a USB slave for serial comms so a direct USB cable with Virtual Serial Port on the PC-side.

jknilinux

Hi,

How does the Hyperterminal/full duplex serial connection work, and how do I set it up? Or, how do I make the propeller a slave USB device? Sorry, I'm a bit of a noob with microcontrollers. Thanks!

Phil Pilgrim (PhiPi)

You will also have to write a "supervisor" program for the Propeller that can interpret commands from the laptop and do the things that are commanded. For example, if you had two one-letter commands, "F" for Forward and "R" for Reverse, say, your supervisor program might have a section that looks like this:

    cmd := Serial.rx
    if (cmd == "F")
      GoForward
    elseif (cmd == "R")
      GoBack

where Serial refers to the FullDuplexSerial object, and GoForward and GoBack are your own routines that do the actual moving.

-Phil

Update: Of course that's Serial.rx, not Serial.getc. So much for memory.

Post Edited (Phil Pilgrim (PhiPi)) : 3/18/2008 6:23:26 PM GMT

Graham Stabler

jknilinux,

The programming USB interface can be used for serial comms because it emulates a serial port at the PC end.

Graham

grasshopper

Hyper terminal is an older program that comes with windows to communicates on various ports that the laptop or computer has a drive written for. Just make your propeller program shoot a string of data out to the computer and while running hyper terminal you'll receive the string.

I should finish my program that is slightly better than hyper terminal for others to use

jknilinux

Hi,

Thanks for the help, but can anyone give me a quick example or how-to with the full duplex serial object/USB interface?

grasshopper

here try this using hyper terminal

CON
  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

 
OBJ 

  SER   :"Fullduplexserial"
  
    
pub start   | TEMP_data
  temp_data := 100
  
  SER.start(31, 30, 0, 9600)                            'Sets up Com port for computer (Rxpin,TXpin,mode,baud)
  repeat
   waitcnt(100_000 * 20 + cnt)
   ser.tx(10)                                            'line feed
    ser.tx(13)                                            'carriage return
    ser.str(string("Results =   "))    
    ser.dec(TEMP_data)                                    'display decimal value of temp
    ser.str(string("binary value is   "))     
    ser.bin(TEMP_data,16)                                 'display binary value of temp 
    ser.tx(13)                                            'line feed
    ser.tx(10)                                            'carriage return
             

make sure you have the Fullduplexserial object

tpw_man

The Parallax Objects Lab has some wonderful usage examples for fullduplexserial. Here is short code for using it.

CON
_clkmode = xtal1 + pll16x         'set clock frequency 
_xinfreq = 5_000_000

OBJ
serial : "FullDuplexSerial"          'fullduplexserial object

PUB main
serial.start(31, 30, 1, 9600)       'start fullduplexserial on the programming pins, with inverted communications, at a baudrate of 9600
serial.str(string("Hello World!"))    'transmit the string Hello World! 

This code will work with the default hyperterminal settings.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
I am 1010, so be surprised!

jknilinux

Hi,

How could I make the computer talk to different Cogs, though? Great answers!

Phil Pilgrim (PhiPi)

As I alluded to above, the computer doesn't "talk to different cogs". You have to write a supervisor program for the Propeller that reads commands from the serial port and causes the commands to be executed. The Propeller, by itself, has no way to interpret what an external device, like a PC, tells it to do, aside from loading programs into RAM or EEPROM.

-Phil

Post Edited (Phil Pilgrim (PhiPi)) : 3/18/2008 7:23:09 PM GMT

Martin Hebel

You are jumping into a pretty sophisticated application. I highly recommend you start with the basics of the Propeller (use the PEK labs, etc) and work up to this level, or people here will have to end up doing it for you. I don't mean to sound mean, but I it's hard to give answers for which you'll have 20 more questions.

-Martin

jknilinux

Hi Everyone,

You have a good point, martin, and I will start small. I was just asking these questions to see if it what I wanted to do was possible, before I buy a whole propeller dev kit. Last question: How hard will it be to do all this? I don't want to be working on communication for two weekends or something. Sorry about the newb questions... Thanks!

tpw_man

Doing raw communications is pretty easy, but it is a slight bit harder to interpret the commands and make a command set that suits your application.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
I am 1010, so be surprised!

Phil Pilgrim (PhiPi)

jknilinux said...
Last question: How hard will it be to do all this? I don't want to be working on communication for two weekends or something.

That will depend on how quick a study you are.

Seriously, it sounds like a worthwhile goal, regardless of the time spent. Besides, if any of us knew ahead of time how much was involved with the projects we do, we probably wouldn't start most of them! Such is life.

Good luck with your project!
-Phil

StefanL38

hello jknilinux,

tell us about your programming skills on PCs. This will help to adjust the level of the answers that were posted here in the forum.

Minimum would be to answer with one o the following choices:

a.) i'm a complete newbie to programming at all on PCs and for microcontrollers

b.) i made some simple programs in a high level language like visual basic, delphi, java

c.) i made quite a lot programs in a high level language like visual basic, delphi, java

d.) i have developed a lot of applications in c/c++ using the windows API but never programmed a serial connection

So make a choice for one of the letters a-d.

Even better would be to answer in complete sentences what kind of programs in which language you made on a PC

It's sure possible to start learning programming with SPIN - the propellerlanguage.
But it will start with lower things than controlling a robot.

Your former questions showed that your understanding of the propeller is not very deep.

That's REALLY REALLY OK. But asking for quick examples for controlling a robot is NOT possible, because this is a quite complex thing.
There are NO QUICK examples for doing that. Except somebody has finished a project and could paste "quickly" his complete sourcecode
which will have hundreds or thousands of commands in summary.

Without a deeper knowledge about programming and the propellerhardware you would be only able to rebuild exact the same robot
loading up the software and maybe making small changes like changing some words showing on a LC-Display


If you ask for specific and concrete details you will get a lot of help here. As long as we (all the other members of the forum) can see
that YOU thought about the last answer and made some steps forward BY YOURSELF and then comes up a new but CONCRETE question
you can ask three times every day and you will get answers.

I guess most of us do not like to write a one week tutorial about programming a robot as ONE PIECE for you.
And even then it would not be clear where your specific problems are. Maybe the tutorial would say a lot of about things you know
very well and things you do not now are short in two sentences. So the best way is if you are asking very CONCRETE questions

best regards

Stefan

jknilinux

Hi Stefan,

I have some experience with C, C++, Java, PBasic, and Assembly, but never used I/O such as serial ports. I certainly never wanted anyone to write a one-week tutorial; when I asked for a small example I meant 5 lines of pseudocode. Sorry about the dumb questions. I know my understanding of the propeller will improve when I get one. Thanks!

Mike Green

You should have a reasonably easy time since Spin is very much like C. Start off just forgetting that there are 8 cogs. Think of them as peripheral processors that will take care of putting up a display or handling servos or sensors or managing a serial channel. That's often how they're used anyway. Once you get comfortable with Spin and with the Propeller Tool, you can use some of the tutorials in the Propeller Education Kit to begin experimenting with forking tasks to other processors yourself.

jknilinux

Sounds great mike- I'll do that. Just wanted to ask if I could connect them instead of buying one and finding out later that it was impossible in the first place. Thanks everybody!