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TM4C129XNCZAD: tm4c129

gurpreet singh
Intellectual 350 points
Part Number: TM4C129XNCZAD

dear ,

          actually i want to send data to DAC 7731 i have written code for this but i am unable to get the output of DAC. i am using SSI port of TM4C129XNCZAD  and i am using PA2 as a SCLK PA3 as  a Chip select and PA4 for sending data. DAC output is sitting at mimimum value although SSI output seems correct i am enclosing code please tell me where i am wrong please help me

int main(void)
{
uint32_t pui32DataTx;

ui32Loop = SYSCTL_RCGCGPIO_R;
SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
SYSCTL_XTAL_16MHZ);
MT_SysTick_Set();

SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI0);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
GPIOPinConfigure(GPIO_PA2_SSI0CLK);
GPIOPinConfigure(GPIO_PA3_SSI0FSS);
GPIOPinConfigure(GPIO_PA4_SSI0RX);
GPIOPinConfigure(GPIO_PA5_SSI0TX);
GPIOPinTypeSSI(GPIO_PORTA_BASE, GPIO_PIN_5 | GPIO_PIN_4 | GPIO_PIN_3 | GPIO_PIN_2);
SSIConfigSetExpClk(SSI0_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE_3,
SSI_MODE_MASTER, 1000000, 8);


SSIEnable(SSI0_BASE);
DAC_ldac();
while(1)
{

MAP_GPIOPinWrite(GPIO_PORTS_BASE, GPIO_PIN_7,GPIO_PIN_7);

pui32DataTx=0x5472;
SSIDataPut(SSI0_BASE, pui32DataTx);
while(SSIBusy(SSI0_BASE))
{
}
SSIIntClear(SSI0_BASE,SSI_RXFF);
SysCtlDelay(100);
MAP_GPIOPinWrite(GPIO_PORTS_BASE, GPIO_PIN_7, 0);
SysCtlDelay(100);
MAP_GPIOPinWrite(GPIO_PORTS_BASE, GPIO_PIN_7, GPIO_PIN_7);  //LDAC rising edge

}


}

void DAC_ldac()
{
MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOS);
MAP_GPIOPinTypeGPIOOutput(GPIO_PORTS_BASE, GPIO_PIN_7);
MAP_GPIOPinWrite(GPIO_PORTS_BASE, GPIO_PIN_7, GPIO_PIN_7);
MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);
MAP_GPIOPinTypeGPIOOutput(GPIO_PORTE_BASE, GPIO_PIN_1);
MAP_GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_1, 0);
}

  • 0
    Guru 117855 points

    (Actually) - your post's "body" very well describes your objective - while your "all important Subject/Headline" borders upon (pardon) USELESS!     (you may easily edit away the nonsensical "part repetition" replacing that "total vagueness" with your "REAL OBJECTIVE" - making your post "far more compelling" to your "US Holiday (still working) helper crüe.

    Now you state:

    gurpreet singh96 said:
    using PA2 as a SCLK PA3 as  a Chip select and PA4 for sending data.

    Yet your code reveals:

    GPIOPinConfigure(GPIO_PA4_SSI0RX);

    GPIOPinConfigure(GPIO_PA5_SSI0TX);  //  does not "this pin" provide (your desired) SPI OUTPUT?

    That's a rather clear conflict (PA4 usage) - is it not?       You cannot realize signal output from the SSIORX (receive) pin!   (RX = Receive, TX = Transmit)

    Have you confirmed (as always) that power is proper AND always present at your DAC?     Is that DAC accepting of 3V3 levels - output by TM4C?

    Your code is devoid of delays - and "Checking for Peripheral Readiness" - both (may) prove harmful to your success.    (but first - fix the RX/TX mash-up!)

    In all such cases - your use of a scope - and presentation of key scope caps - immensely aids remote diagnosis.     And a "proper" (i.e. somewhat communicating Subject Line) surely, "Draws more eyes to your post!"

  • 0 in reply to cb1_mobile
    Intellectual 350 points
    sorry for not using proper subject
    thanks for reply
    whatever data my writing i am able to watch at PA4 this i am giving to SDI of DAC 7731 through 74LS245.
    my DAC output is unaffected by the dac data
  • 0 in reply to gurpreet singh
    Guru 117855 points

    No one "wants" your sorrow - it IS unfortunate that you, "So well describe your goal" - yet that NEVER appears w/in the Subject Line - which "Draws others to your post!"

    You may quickly/easily "EDIT Away" your "weak/non enticing" Subject Line - w/"SPI DAC non-responsive!"       (such proves far more descriptive - and compelling -does it not?)

    You did not respond to my clear identification of your conflicted writing re: PA4.

    Is PA4 truly the SPI TX OUTPUT - as seen by your MCU - and "sent" to your DAC?       Look again @ my post - which clearly identified (via highlight) your conflicting description.     (Re: PA4)

  • 0 in reply to cb1_mobile
    Guru 27665 points

    cb1_mobile said:

    That's a rather clear conflict (PA4 usage) - is it not?       You cannot realize signal output from the SSIORX (receive) pin!   (RX = Receive, TX = Transmit)

    Have you confirmed (as always) that power is proper AND always present at your DAC?     Is that DAC accepting of 3V3 levels - output by TM4C?

    Both of theses points are worth emphasizing. The latter if only because the part is labeled as a Burr Brown part and so dates back to that illustrious companies acquisition.

    Robert

  • 0 in reply to Robert Adsett
    Guru 117855 points

    Well noted - it is a "shame" to see those (famed & pioneering) tech firms become "swallowed" - w/many (skilled) staff dispatched.     (a la - more recently - "National semi-circle" equally departed - and of course, "Luminary Micro" - responsible for our arrival, here...

    Poster's use of 'LS245 w/in SPI realm - defies my imagination. (unless he hopes for "level-shift" via that device...)      Appears that "lack of output from the DAC" has inflicted itself upon posting - as well...

    And - should BP's Turkey have "escaped his barren yard - slipped across the border - and "find itself (now) upon (your) dinner table" - be sure to "chew around" those "metal bits" (lead I'm told) "gobbled from bird's stay @ the FET burial ground."

  • 0 in reply to Robert Adsett
    Intellectual 350 points
    i have corrected still problem exist
    SysCtlPeripheralEnable(SYSCTL_PERIPH_SSI0);
    SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
    GPIOPinConfigure(GPIO_PA2_SSI0CLK);
    GPIOPinConfigure(GPIO_PA3_SSI0FSS);
    GPIOPinConfigure(GPIO_PA4_SSI0TX);
    GPIOPinConfigure(GPIO_PA5_SSI0RX);
    GPIOPinTypeSSI(GPIO_PORTA_BASE, GPIO_PIN_5 | GPIO_PIN_4 | GPIO_PIN_3 | GPIO_PIN_2);
    SSIConfigSetExpClk(SSI0_BASE, SysCtlClockGet(), SSI_FRF_MOTO_MODE_3,
    SSI_MODE_MASTER, 100000, 16);

    PA4 as a transmitting data

    dac Vih minimum is 3.5V
    but i am using 74ls245 for this for conversion
    please help me
  • 0 in reply to gurpreet singh
    Guru 27665 points
    OK, what do the clock and data waveforms look like on the input and output of the '245?

    You should be able to share an oscilloscope capture.

    Robert
  • 0 in reply to Robert Adsett
    Intellectual 350 points

    output of 245

    yellow one is LDAC, green is clock, voilet is chip select pink is data(outtput of PA4)

  • 0 in reply to gurpreet singh
    Guru 117855 points

    Does the Green (SPI Clock) signal trace (only channel set to 10V/Div) not appear "excessive" in level?      Is that DAC accepting of such (well beyond) 5V signal levels?    (it DOES appear that the '245 is employed as "level shifter" - advanced earlier by this reporter)

    Poster Robert (properly) sought (BOTH) input & output waveforms of '245 - yet your caps appear to be (one would hope) "Output only!"     (your unadjusted scope probes and/or ground connection - inflict substantial over/under-shoot upon the cap.)

    Unstated is the "SPI Data" you were trying to send to the DAC - and "Why you chose - and believe" - that data to be correct & proper.     (You've provided NO comment in that regard - forcing extra effort upon your hapless "helpers.")