RTOS/AM5716: SYSBIOS Timer Accuracy?

Please refer to the TI RTOS notes about configuring timers here:

http://processors.wiki.ti.com/index.php/Processor_SDK_RTOS:_TI_RTOS_Tips_And_Tricks#How_to_get_accurate_clock_ticks_from_the_clock_module.3F 

For reference please look at  the pm_a5.cfg file in the PM LLD driver example located here:

pdk_am437x_1_0_10\packages\ti\drv\pm\examples\pmrtos\pm_a15.cfg

Syntax to configure timer and set the input clock correctly:

/***********************************************
* Timer Module Configuraion *
***********************************************/
/* Assign GPTimer2 to be used for Timestamp */
/* Set to 1-ms Tick and Enable Wakeup for OVF interrupt */
var Timer = xdc.useModule('ti.sysbios.timers.dmtimer.Timer');
var timerParams = new Timer.Params();
timerParams.period = 1000 * 10;
timerParams.twer.ovf_wup_ena = 1;
timerParams.tiocpCfg.emufree = 1;
timerParams.tsicr.posted = 0;
/* Timer ID = 1 for GPTimer2 and input clock runs at 20 MHz */
Timer.intFreqs[1].hi = 0;
Timer.intFreqs[1].lo = 20000000;
Timer.create(1, '&mainTimerTick', timerParams);

/* Assign GPTimer3 to be used for Timestamp */
/* Timer ID = 2 for GPTimer3 and input clock runs at 20 MHz */
var DMTimer = xdc.useModule('ti.sysbios.timers.dmtimer.Timer');
var timerParams2 = new DMTimer.Params();
timerParams2.tsicr.posted = 0;
DMTimer.intFreqs[2].hi = 0;
DMTimer.intFreqs[2].lo = 20000000;
var DMTimestampProvider = xdc.useModule("ti.sysbios.timers.dmtimer.TimestampProvider");
DMTimestampProvider.timerId = 2;
DMTimestampProvider.useClockTimer = false;
var Timestamp = xdc.useModule("xdc.runtime.Timestamp");
Timestamp.SupportProxy = DMTimestampProvider;

/* Indicate GPT2 & GPT3 are used */
var TimerSupport = xdc.useModule('ti.sysbios.family.shared.vayu.TimerSupport');
TimerSupport.availMask = 0x0006;

Set the value highlighted in yellow to OSCIN that is input clock to DMtimer on the device.

Hope this helps.

Regards,

Rahul