Beagle Bone Black, PRU not able to initialize PWMSS0 or PWMSS1.

Hi,

Please check this wiki: processors.wiki.ti.com/.../Linux_Core_PWM_User's_Guide

Not LINUX, I need to use the PRU to control the eQEP perpherals

check this link:     http://processors.wiki.ti.com/index.php/PRU_Training:_PRU_PID_Motor_Demo

Need to use the PRU's in a five motor PID loop control. The above referenced demo initializes and  uses the eQEP, I need to access the ehrpwm modules in the eQEP.

Here is  my complete eQEP & ehrpwm initialization:

    // allow external memory reads
    CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;

    /* ***************************************************************
     * eQEP0
     */
    while (!(CM_PER_EPWMSS0 & 0x2)) {
        CM_PER_EPWMSS0 |= 0x2;
    }

    PWMSS0.EQEP_QDECCTL = 0x00;

    /* Enable unit timer
     * Enable capture latch on unit time out
     * Enable quadrature position counter
     * Enable software loading of position counter
     * Reset position counter on unit time event to gauge RPM
     */
    PWMSS0.EQEP_QEPCTL = 0x308E;

    /* Set prescalers for EQEP Capture timer and UPEVNT */
    /* Note: EQEP Capture unit must be disabled before changing prescalar */
    PWMSS0.EQEP_QCAPCTL = 0x0073;

    /* Enable EQEP Capture */
    PWMSS0.EQEP_QCAPCTL |= 0x8000;

    /* Enable unit time out interupt */
    PWMSS0.EQEP_QEINT |= 0x0800;

    /* Clear encoder count */
    PWMSS0.EQEP_QPOSCNT_bit.QPOSCNT = 0x00000000;

    /* Set max encoder count */
    PWMSS0.EQEP_QPOSMAX_bit.QPOSMAX = UINT_MAX;

    /* Clear timer */
    PWMSS0.EQEP_QUTMR_bit.QUTMR = 0x00000000;

    /* Set unit timer period count */
    /*  QUPRD = Period * 100MHz */
    PWMSS0.EQEP_QUPRD_bit.QUPRD = 0x007FFFFF; // (~1/12s) @ 100MHz

    /* Clear all interrupt bits */
    PWMSS0.EQEP_QCLR = 0xFFFF;

    // from AM335x Sitara Processors, TRF Table 15-20 pg. 2262
    // initialization for Figure 15-28 pg. 2261
    PWMSS0.EPWM_TBPRD = 600;    //Period = 601 TBCLK counts
    PWMSS0.EPWM_TBPHS = 0;        //Clear Phase Register to 0
    PWMSS0.EPWM_TBCNT = 0;        //Clear TB counter
    PWMSS0.EPWM_TBCTL = 0x30;    // Phase loading disabled, TBCLK = SYSCLK
    PWMSS0.EPWM_CMPA = 350;        // Compare A = 350 TBCLK counts
    PWMSS0.EPWM_CMPB = 200;        // Compare B = 200 TBCLK counts
    PWMSS0.EPWM_CMPCTL = 0x0;    // Load A on CTR = 0, Load B on CTR = 0
    PWMSS0.EPWM_AQCTLA = 0x12;
    PWMSS0.EPWM_AQCTLB = 0x102;

    /* ****************************************************************
     * eQEP1
     */
    while (!(CM_PER_EPWMSS1 & 0x2)) {
        CM_PER_EPWMSS1 |= 0x2;
    }

    PWMSS1.EQEP_QDECCTL = 0x00;

    /* Enable unit timer
     * Enable capture latch on unit time out
     * Enable quadrature position counter
     * Enable software loading of position counter
     * Reset position counter on unit time event to gauge RPM
     */
    PWMSS1.EQEP_QEPCTL = 0x308E;

    // Set prescalers for EQEP Capture timer and UPEVNT
    // Note: EQEP Capture unit must be disabled before changing prescalar
    PWMSS1.EQEP_QCAPCTL = 0x0073;

    // Enable EQEP Capture
    PWMSS1.EQEP_QCAPCTL |= 0x8000;

    // Enable unit time out interupt
    PWMSS1.EQEP_QEINT |= 0x0800;

    // Clear encoder count
    PWMSS1.EQEP_QPOSCNT_bit.QPOSCNT = 0x00000000;

    // Set max encoder count
    PWMSS1.EQEP_QPOSMAX_bit.QPOSMAX = UINT_MAX;

    // Clear timer
    PWMSS1.EQEP_QUTMR_bit.QUTMR = 0x00000000;

    // Set unit timer period count
    //  QUPRD = Period * 100MHz
    PWMSS1.EQEP_QUPRD_bit.QUPRD = 0x007FFFFF; // (~1/12s) @ 100MHz

    // Clear all interrupt bits
    PWMSS1.EQEP_QCLR = 0xFFFF;

    PWMSS1.EPWM_TBPRD = 600;
    PWMSS1.EPWM_TBPHS = 0;
    PWMSS1.EPWM_TBCNT = 0;
    PWMSS1.EPWM_TBCTL = 0x30;
    PWMSS1.EPWM_CMPA = 350;
    PWMSS1.EPWM_CMPB = 200;
    PWMSS1.EPWM_CMPCTL = 0x0;
    PWMSS1.EPWM_AQCTLA = 0x12;
    PWMSS1.EPWM_AQCTLB = 0x102;


    /*
     * eQEP2
     */
    while (!(CM_PER_EPWMSS1 & 0x2)) {
        CM_PER_EPWMSS2 |= 0x2;
    }

    PWMSS2.EQEP_QDECCTL = 0x00;

    /* Enable unit timer
     * Enable capture latch on unit time out
     * Enable quadrature position counter
     * Enable software loading of position counter
     * Reset position counter on unit time event to gauge RPM
     */
    PWMSS2.EQEP_QEPCTL = 0x308E;

    // Set prescalers for EQEP Capture timer and UPEVNT
    // Note: EQEP Capture unit must be disabled before changing prescalar
    PWMSS2.EQEP_QCAPCTL = 0x0073;

    // Enable EQEP Capture
    PWMSS2.EQEP_QCAPCTL |= 0x8000;

    // Enable unit time out interupt
    PWMSS2.EQEP_QEINT |= 0x0800;

    // Clear encoder count
    PWMSS2.EQEP_QPOSCNT_bit.QPOSCNT = 0x00000000;

    // Set max encoder count
    PWMSS2.EQEP_QPOSMAX_bit.QPOSMAX = UINT_MAX;

    // Clear timer
    PWMSS2.EQEP_QUTMR_bit.QUTMR = 0x00000000;

    // Set unit timer period count
    //  QUPRD = Period * 100MHz
    PWMSS2.EQEP_QUPRD_bit.QUPRD = 0x007FFFFF; // (~1/12s) @ 100MHz

    // Clear all interrupt bits
    PWMSS2.EQEP_QCLR = 0xFFFF;

// not in use ,
//    PWMSS2.EPWM_TBPRD = 600;
//    PWMSS2.EPWM_TBPHS = 0;
//    PWMSS2.EPWM_TBCNT = 0;
//    PWMSS2.EPWM_TBCTL = 0x30;
//    PWMSS2.EPWM_CMPA = 350;
//    PWMSS2.EPWM_CMPB = 200;
//    PWMSS2.EPWM_CMPCTL = 0x0;
//    PWMSS2.EPWM_AQCTLA = 0x12;
//    PWMSS2.EPWM_AQCTLB = 0x102;
//

Please read TRM pg 2261 & 2262

Regards,

Mike

Michael Brainerd said:

    while (!(CM_PER_EPWMSS0 & 0x2)) {
        CM_PER_EPWMSS0 |= 0x2;
    }

You should simply write

CM_PER_EPWMSS0 = 2;

Everything except the lowest two bits are read-only, so there's no need for a read-modify-write.  Also, the proper field to poll is the IDLEST field (bits 17:16).

Michael Brainerd said:

    /*
     * eQEP2

Here is  my complete eQEP & ehrpwm initialization:

     */
    while (!(CM_PER_EPWMSS1 & 0x2)) {
        CM_PER_EPWMSS2 |= 0x2;
    }[/quote]

Looks like you have a copy/paste error here.  You have a mix of PWMSS1 and PWMSS2.

What do you see when you look at the PWM registers?  Are the values you programmed there as expected?  Do timers appear to be running?  Do you get interrupts (if expected)?

This code is from your DEMO.

while (!(CM_PER_EPWMSS0 & 0x2)) {
CM_PER_EPWMSS0 |= 0x2;
}

PLEASE LOOK AT THIS DEMO OF YOURS....
processors.wiki.ti.com/.../PRU_Training:_PRU_PID_Motor_Demo

This is my base application, except instead of PRU eCAP pwm generation I need to use the PWMSS ehrpwm modules.

This I fixed, still no PWM.

while (!(CM_PER_EPWMSS1 & 0x2)) {
CM_PER_EPWMSS2 |= 0x2;
}

I have put togather a test app using PWMSS1 running on JTAG debugger.

Here is the source:

void initEqepPWM(void)
{

// allow external memory reads
CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;

share_buff.enc_rpm[1] = 0;

/* ****************************************************************
* eQEP1
*/
CM_PER_EPWMSS1 = 2;

PWMSS1.EQEP_QDECCTL = 0x00;

/* Enable unit timer
* Enable capture latch on unit time out
* Enable quadrature position counter
* Enable software loading of position counter
* Reset position counter on unit time event to gauge RPM
*/
PWMSS1.EQEP_QEPCTL = 0x308E;

// Set prescalers for EQEP Capture timer and UPEVNT
// Note: EQEP Capture unit must be disabled before changing prescalar
PWMSS1.EQEP_QCAPCTL = 0x0073;

// Enable EQEP Capture
PWMSS1.EQEP_QCAPCTL |= 0x8000;

// Enable unit time out interupt
PWMSS1.EQEP_QEINT |= 0x0800;

// Clear encoder count
PWMSS1.EQEP_QPOSCNT_bit.QPOSCNT = 0x00000000;

// Set max encoder count
PWMSS1.EQEP_QPOSMAX_bit.QPOSMAX = UINT_MAX;

// Clear timer
PWMSS1.EQEP_QUTMR_bit.QUTMR = 0x00000000;

// Set unit timer period count
// QUPRD = Period * 100MHz
PWMSS1.EQEP_QUPRD_bit.QUPRD = 0x007FFFFF; // (~1/12s) @ 100MHz

// Clear all interrupt bits
PWMSS1.EQEP_QCLR = 0xFFFF;

share_buff.pwm_out[AZIMUTH] = DUTY_CYCLE_2;
share_buff.pwm_out[ELEVATION] = DUTY_CYCLE_2;

PWMSS1.EPWM_TBPRD = PERIOD_CYCLES;
PWMSS1.EPWM_TBPHS = 0;
PWMSS1.EPWM_TBCNT = 0;
PWMSS1.EPWM_TBCTL = 0x30;
PWMSS1.EPWM_CMPA = share_buff.pwm_out[AZIMUTH];
PWMSS1.EPWM_CMPB = share_buff.pwm_out[ELEVATION]; // elevation
PWMSS1.EPWM_CMPCTL = 0x0;
PWMSS1.EPWM_AQCTLA = 0x12;
PWMSS1.EPWM_AQCTLB = 0x102;

uint32_t temp[10];

temp[0] = PWMSS1.EPWM_TBPRD;
temp[1] = PWMSS1.EPWM_TBPHS;
temp[2] = PWMSS1.EPWM_TBCNT;
temp[3] = PWMSS1.EPWM_TBCTL;
temp[4] = PWMSS1.EPWM_CMPA;
temp[5] = PWMSS1.EPWM_CMPB;
temp[6] = PWMSS1.EPWM_CMPCTL;
temp[7] = PWMSS1.EPWM_AQCTLA;
temp[8] = PWMSS1.EPWM_AQCTLB;

// this indicates that the registers are set properly according to the TRM.

for ( ;; ) {

__delay_cycles(150);

// just a trap to look at signals with oscilloscope
if (PWMSS1.EQEP_QPOSCNT_bit.QPOSCNT > 15) {
temp[9] = PWMSS1.EQEP_QPOSCNT_bit.QPOSCNT;
__delay_cycles(10);
}

}
}

Here is my GEL file for this test.

//---------------------------------
// Gel file for AM335x BBB PRU CAPE
// rev 1.1


menuitem "PRU_CAPE"

/* AM335x specific mux bit defines */

#define AM335X_SLEWCTRL_FAST (0 << 6)
#define AM335X_SLEWCTRL_SLOW (1 << 6)
#define AM335X_INPUT_EN (1 << 5)
#define AM335X_PULL_UP (1 << 4)
/* bit 3: 0 - enable, 1 - disable for pull enable */
#define AM335X_PULL_DISA (1 << 3)

#define AM335X_PIN_OUTPUT (0)
#define AM335X_PIN_OUTPUT_PULLUP (AM335X_PULL_UP)
#define AM335X_PIN_INPUT (AM335X_INPUT_EN | AM335X_PULL_DISA)
#define AM335X_PIN_INPUT_PULLUP (AM335X_INPUT_EN | AM335X_PULL_UP)
#define AM335X_PIN_INPUT_PULLDOWN (AM335X_INPUT_EN)

hotmenu PRU_Cape_Init()
{
PRU_PINMUX_Config();
PRU_PRCM_Enable();
PRU_ICSS_Reset();
}

hotmenu PRU_PINMUX_Config()
{

GEL_TextOut("****** PRU Cape PINMUX is being configured ***** \n","Output",1,1,1);


//**********************************************************
// 8 bit latch
//**********************************************************

*((unsigned int*) 0x44e108a0) = AM335X_PIN_OUTPUT | 5; //adr0
*((unsigned int*) 0x44e108a4) = AM335X_PIN_OUTPUT | 5; //adr1
*((unsigned int*) 0x44e108a8) = AM335X_PIN_OUTPUT | 5; //adr2
*((unsigned int*) 0x44e108ac) = AM335X_PIN_OUTPUT | 5; //data 0
*((unsigned int*) 0x44e108b0) = AM335X_PIN_OUTPUT | 5; //data 1
*((unsigned int*) 0x44e108b4) = AM335X_PIN_OUTPUT | 5; //data 2
*((unsigned int*) 0x44e108b8) = AM335X_PIN_OUTPUT | 5; //data 3
*((unsigned int*) 0x44e108bc) = AM335X_PIN_OUTPUT | 5; //enable
*((unsigned int*) 0x44e108e0) = AM335X_PIN_OUTPUT | 5; //reset

*((unsigned int*) 0x44e108d0) = AM335X_PIN_INPUT | 2; // eQEP1A
*((unsigned int*) 0x44e108d4) = AM335X_PIN_INPUT | 2; // eQEP1B
*((unsigned int*) 0x44e108d8) = AM335X_PIN_INPUT | 2; // eQEP1-index
*((unsigned int*) 0x44e108dc) = AM335X_PIN_INPUT | 2; // eQEP1-Strobe

*((unsigned int*) 0x44e1084c) = AM335X_PIN_OUTPUT | 6; // ehrpwm1B


}


hotmenu PRU_PRCM_Enable()
{

GEL_TextOut("\t****** Enabling PRU-ICSS clock ****** \n","Output",1,1,1);

*((unsigned int*) 0x44E000E8 ) |= 0x02; // enabling the pru-icss module taking it out of idle

//CSS_Reset();

}

hotmenu PRU_ICSS_Reset()
{

GEL_TextOut("*\t***** Reseting the PRU-ICSS ******\n","Output",1,1,1);

*((unsigned int*) 0x44E00C00 ) |= 0x2;
*((unsigned int*) 0x44E00C00 ) &= 0xFFFFFFFD;

}

hotmenu PRU0_Pause()
{
GEL_TextOut("*\t***** Halting PRU 0 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a322000) = 0x0;

}

hotmenu PRU1_Pause()
{
GEL_TextOut("*\t***** Halting PRU 1 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a324000) = 0x0;

}

hotmenu PRU0_1_Pause()
{
GEL_TextOut("*\t***** Halting PRU 0 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a322000) = 0x0;

GEL_TextOut("*\t***** Halting PRU 1 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a324000) = 0x0;

}

hotmenu PRU0_Start()
{
GEL_TextOut("*\t***** Starting PRU 0 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a322000) = 0x2;

}

hotmenu PRU1_Start()
{
GEL_TextOut("*\t***** Starting PRU 1 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a324000) = 0x2;

}

hotmenu PRU0_1_Start()
{
GEL_TextOut("*\t***** Starting PRU 0 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a322000) = 0x2;

GEL_TextOut("*\t***** Starting PRU 1 ******\n","Output",1,1,1);
*((unsigned int*) 0x4a324000) = 0x2;

}

hotmenu ENABLE_ECAP_LOOP()
{

//**********************************************************
// PRU input
//**********************************************************

// J4 pin 2 = pr1_pru0_gpi15 (GPMC_AD15 - mode 6)
*((unsigned int*) 0x44e1083C) = AM335X_PIN_INPUT | 6; //mode 6

//**********************************************************
// ECAP_PWM output
//**********************************************************

// J4 pin 1 = pr1_ecap0_in_pwm0_out (ECAP0_IN_PWM0_OUT - mode 3)
*((unsigned int*) 0x44e10964) = AM335X_PIN_INPUT | 3; //mode 7
}

According to the TRM this should all work.

Any Ideas?

Regards,
MIke