Problem with Propeller Servo Controller USB

LarryPotter · 2010-06-10 14:55

I purchased a Propeller Servo Controller USB·to control Parallax's Motor Mount and Wheel Kit with Position Controller.· I am using the [size=-1]Flashlite 386Ex[/size]·by JK Microsystems for the controller.· I am using the C programming language.· I have not been successful in sending commands to the Propeller Servo Controller.· I am using a serial connection.· The servo controller does work fine when I send commands with the Basic Stamp, so I know that the problem is not with the hardware.··I wrote to Parallax and asked if they had·any C programming examples for writing to this controller, and they directed me to this·forum.· Incidentally,·this is a robot project, and I am using [size=-1]eRTOS[/size]·to allow multitasking.·

Post Edited By Moderator (Bean) : 6/10/2010 3:12:56 PM GMT

Bean · 2010-06-10 15:09

Are you sure the serial output is the correct polarity (True or inverted) ?

Bean

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Use BASIC on the Propeller with the speed of assembly language.
PropBASIC thread http://forums.parallax.com/showthread.php?p=867134

March 2010 Nuts and Volts article·http://www.parallax.com/Portals/0/Downloads/docs/cols/nv/prop/col/nvp5.pdf
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There are two rules in life:
· 1) Never divulge all information
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If you choose not to decide, you still have made a choice. [noparse][[/noparse]RUSH - Freewill]

allanlane5 · 2010-06-10 17:42

If you have the USB version of the servo-controller, how are you talking to it without a USB port on the Flashlite?

Also, I believe the BS2 talks to it with "RS232-TTL" signals -- and yes, they may be inverted from what the Flashlite is trying.

Mike G · 2010-06-10 18:04

If you're not using the PSC's USB port, you'll need to supply proper power and ground to the electronics (not the same as servo power). 5V to the center pin (+) on of the the "serial in" port on the PSC and ground (-). Make sure properly ground your circuit. The signal line is a single wire so how are you connecting your serial communication? Through a tri-state or maybe a PNP/NPN circuit?

As for C code... that's dependent on your hardware and OS. You might want to contact Flashlite and/or eRTOS support?

Post Edited (Mike G) : 6/10/2010 8:48:30 PM GMT

Mike G · 2010-06-10 22:06

Here's a simple "Get the PSC Version" in C running on windows. The PC is connected to the PSC through the USB port. Hope this helps.

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

//Setup the serial port
void serialConfig(HANDLE h, long baud);

int main(int argc, char **argv)
{
    HANDLE serial_port;                /* Handle to the serial port */

    long baud_rate = 2400;            /* Specified baud rate */
    //char port_name[noparse][[/noparse]] = "COM6";        /* Name of the serial port */

    // Get PSC version
    //&#8220;!SCVER?&#8221; <CR>
    char pscVer[noparse][[/noparse]] = {"!SCVER?\r"};

    unsigned long bytes_written;    /* Bytes written to serial port */


    
    // Open up a handle to the serial port
    //serial_port = CreateFileA(port_name, GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0);

    serial_port = CreateFile(TEXT("COM6"), GENERIC_READ | GENERIC_WRITE, 0, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

    // Make sure port was opened
    if (serial_port == INVALID_HANDLE_VALUE)
    {
        fprintf(stderr, "Error opening port\n");
        CloseHandle(serial_port);
        exit(0);
    }

    // Set up the serial port
    serialConfig(serial_port, baud_rate);

    // Send the PSC version command
    WriteFile(serial_port, pscVer, sizeof(pscVer), &bytes_written, NULL);
    printf("\nTransmitted !SCVER? [noparse][[/noparse]%lu bytes]\n", sizeof(pscVer));


    DWORD dwBytesRead = 0;
    char buffer[noparse][[/noparse]13];
    buffer[noparse][[/noparse]12] = '\0';

    // Read the serial port
    ReadFile(serial_port, buffer, 12, &dwBytesRead, NULL);
    printf("\nVersion %s \n", &buffer[noparse][[/noparse]9]);

    // Close the handle
    CloseHandle(serial_port);

    return 0;
}

void serialConfig(HANDLE h, long baud)
{
    DCB properties;            /* Properties of serial port */

    /* Get the properties */
    GetCommState(h, &properties);

    /* Set the baud rate */
    switch(baud)
    {
    case 1200:
        properties.BaudRate = CBR_1200;
        break;
    case 2400:
        properties.BaudRate = CBR_2400;
        break;
    case 4800:
        properties.BaudRate = CBR_4800;
        break;
    case 9600:
        properties.BaudRate = CBR_9600;
        break;
    case 14400:
        properties.BaudRate = CBR_14400;
        break;
    case 19200:
        properties.BaudRate = CBR_19200;
        break;
    case 38400:
        properties.BaudRate = CBR_38400;
        break;
    default:
        fprintf(stderr, "Invalid baud rate: %ld", baud);
        exit(0);
        break;
    }
    
    /* Set the other properties */
    properties.Parity = NOPARITY;
    properties.ByteSize = 8;
    properties.StopBits = ONESTOPBIT;

    SetCommState(h, &properties);

    return;
}

Post Edited (Mike G) : 6/10/2010 10:17:25 PM GMT

LarryPotter · 2010-06-12 15:03

Thank you Bean, allanlane5, and Mike G. After writing my post, I had realized that the serial port on the 386Ex was inverted. So I used a 74LS04 on the transmit line to invert it. As far as the voltages, I do have 5 volts and grond supplied to the serial input of the servo controller. For my C code, I filled a byte array (insigned char) with the decimal equivalents of the speed command. Using a printf command to view what was being sent to the controller, all looks good. However, still no success. Istill need to look at the code Mike G posted.

So, again, thanks loads guys for the feedback. I will let you know on the forum of any success.

LarryPotter · 2010-06-12 19:56

I finally got the 386Ex to talk to the Parallax Servo Controller.· The problem was the voltage levels.· I used an Acroname Serial Interface Connector I had on hand and now it is working fine.· If anyone is interested, following is the C code I used to drive the controller.

/**************************************************/
/*·················· << Position Command >>··································*/
/*····················································································· */
/*··················· Written by L. Wendell···································· */
/*··············································································· ····· */
/**************************************************/
#include <rtos.h>
#include <sio.h>
#include <stdio.h>
#include <driver.h>
#include <string.h>
#include <stdlib.h>
//void SendCommand(char [noparse]/noparse);··· //Send command function
void SerXmit(BYTE [noparse]/noparse);········· //Serial xmit function
void Com1Init(void);··········· //Serial port initiate func
void MotorTest(void);·········· //Test Motors using PSCU
/**************** Main Thread ************************/
void main(void)
{
·kdebug = 1;
·rt_init( 200 );
·Com1Init();·· //Initiate camera com port (Com 1 386EX)
·rt_sleep(1000);
·rt_newthread(MotorTest, 1, 2048, 0, "MotorTest");
·do{
··rt_sleep(1000);
·}while(1);
}//End of maiin thread
/************** Com1Init function *********************/
void Com1Init(void){····· //ititiate 386Ex Com 1 for camera
·sio_init(1,0x3F8,4,512,512,NULL,0);···· //These are RTOS functions...
·sio_setup(1,2400,8,0,1,0);
}· //End of cam_sio function
/**************** SerXmit function ********************/
void SerXmit(BYTE string[noparse]/noparse){····· //Sends a string to camera.
·int i = 0;
·do{
··sio_writebyte(1,string[noparse][[/noparse]i]);
··//printf("Sent: %i, %c, \n", string[noparse][[/noparse]i], string[noparse][[/noparse]i]);
··printf("Sent: %i \n", string[noparse][[/noparse]i]);
··i++;
··if (string[noparse][[/noparse]i] == NULL) break;
·}while(1);
} //End of SerXmit function
/************** MotorTest Thread ********************/
void MotorTest(){················· //Pos values of sonar_rot = CW rotation
unsigned int ch = 1, ra = 7, pw; //, lonyb, hinyb;
BYTE buffer[noparse][[/noparse]9], lonyb, hinyb;
·do{
··rt_yield();
··pw = 1100;
··lonyb = pw & 255;
··hinyb =(pw & 65280 ) >> 8;
··printf ("%i, %i \n", lonyb, hinyb);
··buffer[noparse][[/noparse]0] = 33;··· //"!"
··buffer[noparse][[/noparse]1] = 83;··· //"S"
··buffer[noparse][[/noparse]2] = 67;··· //"C"
··buffer[noparse][[/noparse]3] = ch;··· //"Channel "0"
··buffer[noparse][[/noparse]4] = ra;··· //rate "7"
··buffer[noparse][[/noparse]5] = lonyb; //Low Byte pulse width
··buffer[noparse][[/noparse]6] = hinyb; //High Byte pulse width
··buffer[noparse][[/noparse]7] = 13;··· //"\r"
··buffer[noparse][[/noparse]8] = NULL;
··SerXmit(buffer);
··rt_sleep(1500);
··pw = 400;
··lonyb = pw & 255;
··hinyb =(pw & 65280 ) >> 8;
····· printf ("%i, %i \n", lonyb, hinyb);
··buffer[noparse][[/noparse]0] = 33;··· //"!"
··buffer[noparse][[/noparse]1] = 83;··· //"S"
··buffer[noparse][[/noparse]2] = 67;··· //"C"
··buffer[noparse][[/noparse]3] = ch;··· //"Channel "0"
··buffer[noparse][[/noparse]4] = ra;··· //rate "7"
··buffer[noparse][[/noparse]5] = lonyb; //Low Byte pulse width
··buffer[noparse][[/noparse]6] = hinyb; //High Byte pulse width
··buffer[noparse][[/noparse]7] = 13;··· //"\r"
····· buffer[noparse][[/noparse]8] = NULL;
··SerXmit(buffer);
··rt_sleep(1500);
·}while(1);
} //End of MotorTest thread
·

Problem with Propeller Servo Controller USB

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