CC1312R: CMD_FS_OFF, CMD_FS_POWERUP and CMD_FS_POWERDOWN

You do not have to turn the synth on an off in your application unless you are changing frequency all the time. Every time the RF Core has been powered down, the power driver will make sure that the setup command and the CMD_FS is executed the next time you want to use the radio.

The nInactivityTimeout can be used for automatic power down. The RF core will then start a timer after the last command in the queue has completed.

The default timeout is "forever" and this feature is disabled.

A more used approach, at least in the proprietary RF examples is to use Manual power-down by calling RF_yield(). The client should do this whenever it knows that no further radio operation will be executed for a couple of milliseconds.

Example:

/* Request access to the radio */
rfHandle = RF_open(&rfObject, &RF_prop, (RF_RadioSetup*)&RF_cmdPropRadioDivSetup, &rfParams);

/* Set the frequency */
RF_postCmd(rfHandle, (RF_Op*)&RF_cmdFs, RF_PriorityNormal, NULL, 0);

while(1)
{
    RF_runCmd(rfHandle, (RF_Op*)&RF_cmdTxTest, RF_PriorityNormal, NULL, 0);

    /* Power down the radio */
    RF_yield(rfHandle);

    /* Sleep for 1 s */
    sleep(1);
}

In the example above, the RF_yield, will power down the radio and the sleep will make the device enter standby for 1 s. When the TX command is issues again, the drivers know that it must first perform a setup command and then a CMD_FS before the radio can be used. Since the device is told to sleep for 1 s, the interval for when the radio transmits a carrier, is slightly above 1 s.

If you want the interval for entering TX to be exactly 1 s, you can use absolute trigger for the start trigger of the TX command:

#define PACKET_INTERVAL (uint32_t)(4000000*1.0f) /* Set packet interval to 1 s */

RF_cmdTxTest.startTrigger.triggerType = TRIG_ABSTIME;

/* Request access to the radio */
rfHandle = RF_open(&rfObject, &RF_prop, (RF_RadioSetup*)&RF_cmdPropRadioDivSetup, &rfParams);

/* Set the frequency */
RF_postCmd(rfHandle, (RF_Op*)&RF_cmdFs, RF_PriorityNormal, NULL, 0);

/* Get current time */
time = RF_getCurrentTime();
while(1)
{
    /* Set absolute TX time to utilize automatic power management */
    time += PACKET_INTERVAL;
    RF_cmdTxTest.startTime = time;

    RF_runCmd(rfHandle, (RF_Op*)&RF_cmdTxTest, RF_PriorityNormal, NULL, 0);
}

In the case above, the drivers will know that you are not going to enter TX again in almost one second, so it will automatically power down the RF Core and power it up again in time to do a setup command and a CMD_FS before the next time it should enter TX.

In both of the example, endTriggers should be used for the TX command, to make it stop transmitting after 50 ms (or whatever time you want).

Siri

What do you mean when you say that you only get usable signals for the first TX. What do you get for the other ones? No signal, a signal on the wrong freq?

I tested it with the newest SDK (4.10) and did not see any problems:

void *mainThread(void *arg0)
{
    RF_Params rfParams;
    RF_Params_init(&rfParams);

    /* Open LED pins */
    ledPinHandle = PIN_open(&ledPinState, pinTable);
    if (ledPinHandle == NULL)
    {
        while(1);
    }

    RF_cmdTxTest.startTrigger.triggerType = TRIG_NOW;
    RF_cmdTxTest.endTrigger.triggerType = TRIG_REL_SUBMIT;
    RF_cmdTxTest.endTime = (uint32_t)(4000000*0.5f); // Transmit for 500 ms

    /* Request access to the radio */
    rfHandle = RF_open(&rfObject, &RF_prop, (RF_RadioSetup*)&RF_cmdPropRadioDivSetup, &rfParams);

    /* Set the frequency */
    RF_postCmd(rfHandle, (RF_Op*)&RF_cmdFs, RF_PriorityNormal, NULL, 0);

    while(1)
    {
        RF_runCmd(rfHandle, (RF_Op*)&RF_cmdTxTest, RF_PriorityNormal, NULL, 0);

        /* Power down the radio */
        RF_yield(rfHandle);

        /* Sleep for 2 s */
        sleep(2);
    }
}

The code above transmit a carrier for 500 ms and then sleep for 2 s, and then it repeats. The application only issue the cmdFS once, but the rf driver runs the command every time it wakes up from sleep.

BR

Siri

There seems to be an issue with the CC13x0 devices when chaining the TX_TEST commands. This is fixed on CC13x2, and I have verified that it works as expected there. You just need to make sure that .config.bFsOff = 0x0 when you are not doing the CMD_FS between the commands.

BR

Siri