CC8521: RF unable to output continuously using PurePath wireless commander

The CC8521 is the same as the CC8520 except that it adds a USB interface, and thus necessitates a higher minimum operating supply voltage.  What hardware differences exist between your board designs to compensate?  Have you monitored the power lines and further evaluated exactly what happens after 3 seconds, for example a device reset?  What happens if you lower the TX power or change any other critical variables? Consider submitting for a SIMPLELINK-2-4GHZ-DESIGN-REVIEWS. 

Regards,
Ryan

After monitor power and data line, we found that:

1. No different between TX on and TX off in powe line

2. No different between CC2541 and CC2540 in powe line

3. No different between CC2541 and CC2540 in MOSI. But we found CMD was different with CC85XX user guide (SWRU250M)

4. A little difference in MISO, but we can't figure out the reason.

Abraham Lee said:

CMD was different with CC85XX user guide (SWRU250M)

Which command specifically?  And what is the voltage level of your design?

Reviewing B.3 EHIF Command Set of SWRU250, it would appear that the CC8521 does not have the EVT_VOL_CHG flag set like with the CC8520.  However, this should not make a difference with the behavior your are experiencing.

Regards,
Ryan

1. CMD is RFT_TXTST_CW.

As JS code list below, the CMD should be: 0X15 0X03 0X01 0X58 0X00

<func status="enabled">
<name>RF test TX only, channel 1 P=5dBm</name>
<call>simpleRfTest(TX,2406,0,-25,CW,1000)</call>
<opinstr>Transmitting continuously on channel 1 ...</opinstr>
<devreq>dut</devreq>
</func>

2. CC8521 and CC8520 Supply Voltage is 3.3V

Whatever the power supply is from external power supply or from CC-DEBUG, the result is the same. The RF output only 3 seconds in CC8521, but it's normal in CC8520 in the same conditions.

Have you tested multiple CC8521 and is the result the same on all of them?  What is the behavior of other RF tests such as RFT_TXTST_PN or RFT_RXTST_CONT?

Regards,
Ryan