CC1350: Issues when setting OOK above 15 kBaud

Scot Cowley

Part Number: CC1350

Hi,

I am using SmartRF Studio V2.10.0 with a CC1350 Rev 2.1 (Rev. B) launchpad. If I configure the symbol rate higher than 14.5kbps the CC1350 sends out a single packet and then does not send any subsequent packets. Even if I lower the symbol rate to 4.8 kBaud after attempting higher than 14.5 kbps. Only if I close and open the Device Control Panel for the launchpad will it work again.

Steps to reproduce:

Open CC1350 launchpad in proprietary mode.
Select Legacy CC11xx settings
Select 4.8 kbps, OOK
Change Frequency to 433.92Mhz and symbol rate to 15kbps
Start transmission

The first packet will send correctly and then no other packets will send.

over 6 years ago

0 TER over 6 years ago

TI__Guru**** 317180 points

To use a different datarate than 4.8 kbps you need to adjust the bit length etc. Please take a look at the overrides described in e2e.ti.com/.../576254

0 Scot Cowley over 6 years ago in reply to TER

Intellectual 816 points

Is there a reason that the CC13xx seems to 'lock up' and require a restart of the device control panel when those overrides aren't set.

I've managed to send multiple packets now using HW_REG_OVERRIDE(0x52B8,0x8006) and HW_REG_OVERRIDE(0x6098,0x1200) but I can't seem to get 50% duty cycle within the bounds of what works and what just causes a lock up. I'll continue testing.

0 Scot Cowley over 6 years ago in reply to Scot Cowley

Intellectual 816 points

I've managed to get it working better by using 31.5kBps (instead of 33.3kBps) with HW_REG_OVERRIDE(0x52B8,0x8010) and HW_REG_OVERRIDE(0x6098,0x1200). It's not that close to 50% and but the legacy code on the receiver allows for the tolerances.

I'm noticing high spikes (40ns) on the low and low spikes on the high pulses in a RF packet.

Is there perhaps any way to improve this?

0 TER over 6 years ago in reply to Scot Cowley

TI__Guru**** 317180 points

I thought the target was 15 kbps? Is this a TX only application?

This patch is developed for low datarates and 20 kbps is the highest we have tested this on. I assume you are referring to the pulse on the zoomed in plot?

0 Scot Cowley over 6 years ago in reply to TER

Intellectual 816 points

Sorry for the confusion. The target is a TX only 33.3kbps - I was more mentioning 15kbps due to the 'lock up' issues when the duty cycle and bit widths aren't set correctly.

Yes the zoomed in pulse, just after the second high signal.

This was my initial post e2e.ti.com/.../725946

0 Scot Cowley over 6 years ago in reply to TER

Intellectual 816 points

Hi TER,

Any ideas on how to clean up the signal (remove spikes) and to possibly improve on the timing for 33.3kbps OOK (TX Only)?

0 TER over 6 years ago in reply to Scot Cowley

TI__Guru**** 317180 points

Since the path is not designed for these datarates and we have never looked into it I can't say why you get spikes. If you try with the 20 kB settings that I linked to at the start of this threads, do you see the spikes then? (meaning is it the settings or something else)

0 TER over 6 years ago in reply to TER

TI__Guru**** 317180 points

Closing this thread due to inactivity.

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CC1350: Issues when setting OOK above 15 kBaud