TM4C129ENCPDT: Output clocks on GPIO pins

See my replay and test code below

Hi Jeff,

  I'm currently on vacation. My response will be very much delayed. Can you take at look at this post?

https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/345762/tiva-c-series-tm4c1294-connected-launchpad

Charles,

I had a little more success, but still seeing one issue.
I can successfully output RTCOSC on PK7.
Using your sample code above, I get the expected SYSCLK output, but when I change it to output the MOSC, which is what we are looking for, I get a 781Khz wave and not the 25Mhz expected.

This is the code I'm running

// Output DIVSCLK on PQ4
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOQ);
while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOQ)) { }

GPIOPinConfigure(GPIO_PQ4_DIVSCLK);
GPIODirModeSet(GPIO_PORTQ_BASE, GPIO_PIN_4, GPIO_DIR_MODE_HW);
GPIOPadConfigSet(GPIO_PORTQ_BASE, GPIO_PIN_4, GPIO_STRENGTH_2MA, GPIO_PIN_TYPE_STD);
SysCtlClockOutConfig(SYSCTL_CLKOUT_EN | SYSCTL_CLKOUT_MOSC, 1);

Charles,

After running many experiments, I discovered there must be some limit to the output of DIVSCLK.
If I divide the clock by 1, it outputs 781k. When I divide it by 10, it outputs 2.5Mhz.
I checked the crystal and verified it’s 25Mhz.
Is this a know issue for outputting the MOSI clock on PQ4?
I don't see anything in the datasheet about this.

Jeff

Thank you